Development of a Montana land cover map from Landsat imagery by Philip William Smith A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Soil Science Montana State University © Copyright by Philip William Smith (1981) Abstract: Landsat color composite transparencies were visually interpreted in an effort to produce an accurate low cost land cover map of Montana. Seven categories of land cover were interpreted and the data transferred directly to a mylar overlay registered to a 1:1,000,000 scale base map. Cover categories included in the state map are range, forest, dryland crops, irrigated crops, alpine areas and rock outcrops, water, and urban areas. The map was compiled at an estimated cost of $0.01/km^2 and showed 90% agreement with existing county land use maps. Upon completion, the land cover map was encoded along with the state soils map for conversion to AREAS, South Dakota State University's computerized geographic information system. Output from AREAS includes the hectares of land occupied by each cover type and each cover type's distribution on Montana's soil associations. The results from AREAS show that range occupies 50%, forest 27%, dryland crops 18%, irrigated crops 3%, alpine and rock outcrops 2%, water 0.5%, and urban less than 0.1% of Montana's total land area. This study demonstrated manual interpretation of Landsat imagery to provide an inexpensive and accurate alternative to conventional surveys for small scale land cover mapping.  STATEMENT OF PERMISSION TO COPY In presenting this thesis in partial fulfillment of the requirements for an advanced degree at Montana State University, I agree that the Library shall make it freely available for inspection. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by my major professor, or, in his absence, by the Director of Libraries. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my written permission. Signature ^ Date DEVELOPMENT OF A.MONTANA LAND COVER MAP FROM LANDSAT IMAGERY by PHILIP WILLIAM SMITH. A thesis submitted in partial fulfillment of the requirements for the degree Of ' . . ' MASTER OF SCIENCE in . Soil Science Approved: Chairperson, Graduate CommBGtfee Head, Majdr Dep^ytment ___________ Graduate Dean MONTANA STATE. UNIVERSITY Bozeman, Montana June, 1981 iii ACKNOWLEDGMENTS I wish to express my appreciation to the following individuals who helped make the completion of this thesis a reality: Dr. Paul Kresge, whose patience perservered throughout this extended degree program of his first graduate student; Dr; Gerald Nielsen, for his input and help in finding enough work to keep me solvent; Dr. Earl Skogley, for his assistance in prescreening and ordering the imagery; and Dr. John Taylor. - My sincerest gratitude is extended to my parents and wife, Jan, whose tolerance, understanding and financial help made this whole endeavor possible. TABLE OF CONTENTS Page VITA . . . i ............................................ ii ACKNOWLEDGMENTS . . . . . . . . . . . ................... iii LIST OF TABLES. . . . . ............... ................... vi LIST OF FIGURES . ................ ............... .. vii ABSTRACT . . . .......... . . . . ! . ......................viii INTRODUCTION..............i . . ....................... I The Need for Land Cover Information and Analysis.................................. I LITERATURE REVIEW ........ 3 Description of the Landsat Program .............. . 3 Monitoring Land Use from Space Platforms . . . . . . 5 Land Use Surveys from Manned Spacecraft Photography .................. 5 Automated Analysis of Landsat Data .. .-........ 6 Manual Analysis of Landsat Data .............. 7 Geographic Information Systems Using Remote Sensing Data Input . ....................... . . 11 MATERIALS AND METHODS . . ............ .. . . . ......... 15 Classification of Land C o v e r ...................... 15 Identification of Land Cover Types . . . .......... 16 Irrigated Crops . ........................ 16 Dryland C r o p s ......................... 17 Forest........ 18 W a t e r .......... 18 U r b a n ........................................ 19 Alpine and Rock Outcrops...................... 20 R a n g e ......... 20 Encoding of the State Land Coyer M a p .............. 21 Areal Tabulation of Land Cover Categories . ........ 22 Testing Land Coyer Map Accuracy............... 23 Source of Ground Truth D a t a .................. 23 Selection of Ground Truth Sites .............. 24 VTable of Contents (continued) Page RESULTS AND DISCUSSION . . . . ...............' .......... 28 Land Cover Distribution in M o n t a n a ............. . 28 Comparison with Existing Montana Land Use D a t a ...................................... 38 Land Cover Map Classification Accuracy ................ 40 Cost of Land Cover Map Development . . . .............44 Comparison with Other Mapping Projects and M e t h o d s ................................. 45 CONCLUSIONS............■ . . . '...................... .. 48 LITERATURE CITED . . .................................... 50 APPENDICES I INDEX OF LANDSAT IMAGERY USED TO PREPARE THE MONTANA LAND COVER M A P ........'............ 57 II SOURCES OF REMOTE SENSING IMAGERY ..... .......... 59 III MONTANA SOIL ASSOCIATION AND LAND COVER COMBINATIONS . .................................. 65 IV MONTANA SOIL ASSOCIATIONS’ DESCRIPTIONS AND PERCENT LAND COVER .............. . . . . . . . 74 vi LIST OF TABLES Table Page 1 Landsat MSS characteristics ...................... . 4 2 AREAS tabulations For land cover in Montana . . . . . . 30 3 Soil associations with significant range cover . . . . 31 4 Soil associations with significant forest cover . .............................. 33 5 Soil associations with significant dryland crop cover . . ................ 34 6 Soil associations with significant irrigated crop cover.......... 36 7 Soil associations with significant alpine or rock outcrop cover............................. ! 37 8 USDA, ESCS land use statistics for M o n t a n a .......... 38 9 Montana Situation Statement's areal tabulations for water, range, forest, and irrigated crops ........ 40 10 Map accuracy by land cover type............... 41 11 Sample point distribution by land cover categories................................... 43 12. Cost of producing 1:1,000,000 Montana land cover map from manual interpretation of Landsat imagery...................... 45 I-I Index of Landsat imagery used to prepare the Montana land cover map . ............ 58 III-I Montana Soil Association and Land Cover Combinations............................. 66 IV-I Montana soil assocations1 descriptions and percent land cover . i ........... 76 vii LIST OF FIGURES Figure Page 1. Area covered by county land use maps used as ground t r u t h ........... 25 2. Photographic reduction of original 1:1,000,000 Montana land cover m a p ......... 29 MAP SUPPLEMENT I. Computer plotted Montana land cover map viii ABSTRACT Landsat color composite.transparencies were visually inter­ preted in an effort to produce an accurate low cost land cover map of Montana. Seven categories of land cover were interpreted and the data transferred directly to a mylar overlay registered to a 1:1,000,000 scale base map. Cover categories included in the state map are range, forest, dryland crops, irrigated crops, alpine areas and rock outcrops, water, and ur^an areas. The map was compiled at an estimated cost of $0.01/km and showed 90% agreement with existing county land use maps. Upon completion, the land cover map was encoded along with the state soils map for conversion to AREAS, South Dakota State University's computerized geographic information system. Output from AREAS includes the hectares of land occupied by each cover type and each cover type's distribution on Montana's soil associations. The results from AREAS show that range occupies 50%, forest 27%, dryland crops 18%, irrigated crops 3%, alpine and rock outcrops 2%, water 0.5%, and urban less than 0.1% of Montana's total land area. This study demonstrated manual interpretation of Landsat imagery to provide an inexpensive and accurate alternative to conventional surveys for small scale land cover mapping. ■J INTRODUCTION The purpose of this research was to determine the capability and accuracy of manual interpretation of Landsat satellite imagery for inventorying land cover in Montana. Products of this research include a I:1,000,000 scale state land cover map for Montana and areal tabulations for each land cover category and its distribution on the state's soil associations. The Need for Land Cover Information and Analysis Until now, no land cover/use map has been available for Montana. Montana's size and natural resource diversity create a need for a reliable and economical method of land resource inven­ tory. Montana is the fourth largest state in the nation with a total surface area of 235,421 square kilometers (USDI-BLM, 1969). Within this area, the complexity of Montana's geologic, climatic, vegetational and pedologic patterns combine to form a variety of natural ecosystems. Since the demands on these ecosystems are in­ creasing and often conflicting, there is a need for an efficient and cost-effective method of land resource inventory and analysis. The perspective offered by remote sensing from aerial and space plat­ forms provides for the rapid collection of current and detailed land resource data. Particularly valuable is the spatial context of the data, which provides insight into the distribution of resources, 2their areal extent, and proximal relationships (Cox, 1977). These assets make land resource inventories compiled from remote sensing data a viable alternative to more conventional surveys. LITERATURE REVIEW The recording of remotely sensed data from aerial platforms was underway in the late 1800's and early 1900's. In the following years, two world wars and several international crises stimulated rapid advances in remote sensing methods and technology. The conservation-oriented programs of the New Deal helped to initiate large aerial mapping progams in the United States. Many of these programs are still conducted by the USDA and other agencies as part of their natural resource surveys. The manned space program of the 1960' s brought space photog­ raphy into its own and demonstrated the potential for monitoring earth resources from space (Kroeck, 1976). The Landsat satellite series, operational since 1972, adds another dimension to remote sensing from space. Providing repeti­ tive coverage of the earth's surface, Landsat makes possible the continuous monitoring of the earth's natural resources. Description of the Landsat Program The Landsat Program (formerly the Earth Resources Technology Program) was designed as a research and development tool to demon­ strate the usefulness of satellite remote sensing in the management of earth resources (Anonymous, 1977). Since the launching of Landsat-I (formerly ERTS-I) on July 23, 1972, two additional 4satellites, Landsats-2 and -3, have been put in orbit. Although Lahdsat-I exceeded its planned orbital life, at this writing only Landsats-2 and -3 are still producing data. Each satellite was launched into.a near polar, sun-synchronous orbit at an average altitude of 910 kilometers. The sensor design for all three Landsats is similar except for modifications made on Lapdsat-3. Landsat's main sensor system is the multispectral scanner (MSS). The MSS collects radiometric data in four discrete spectral bands within the visible and near infrared spectrum (Anonymous, 1977) (Table I). Upon collection, the data are either transmitted directly to one of the ground receiving stations at Fairbanks, Alaska; Goldstone, California; and Greenbelt, Maryland or stored on tape until the satellite comes in view of a ground station. Table I. Landsat MSS characteristics. Band Wavelength (urn) Spectral Region 4 0.5 - 0.6 green 5 0.6 - 0.7 red 6 0.7 - 0.8 near IR 7 0.8 - 1.1 near IR 5The spacecraft motion produces a continuous strip of data. During image processing at the Ground Data Handling System Facility, this strip of imagery is formed into separate images. These images, called scenes, incorporate a ground coverage area of 185 x 185 kilometers. The lateral ground resolution of the MSS is approxi­ mately 80 meters. Each picture element (pixel) covers a ground area of about 0.4 hectares, but the minimum area resolved is Usually closer to 2 to 4 hectares (Seevers and Peterson, 1978). ' Landsat data are available in either computer compatible tapes (CCTs) containing the digital data of all spectral bands or in a 1 variety of photographic products.(Gonzoles and Sos, 1974). Monitoring Land Use from Space Platforms Starting with photographs from early manned flights, numerous land use studies have.been performed using imagery taken from space platforms. Land Use Surveys from Manned Spacecraft Photography Manual interpretation of Gemini and Apollo manned spacecraft photography was employed to produce generalized land use maps at scales of 1:250,000 and I:1,000,000 for portions of the southwestern United States. . The broad view provided by the photos was found to 6Skylab photography was interpreted visually in an attempt to map land use in the Fairfax, Virginia area. It was established that the Skylab photography filled the gap between the coarser resolution Landsat MSS data and high altitude U-2 plane photography. The Skylab photography enabled the interpreters to map urban structural detail from orbital altitudes. In comparison, urbanized areas could ' be delineated on Landsat MSS images but it was difficult to deter­ mine the specific activities (commercial, industrial, etc.) present (Lins, 1976). Automated Analysis of Landsat Data The format of Landsat products makes possible either manual or automated (computer) interpretation of the MSS' data. Automated techniques, involving the analysis of computer compatible tapes have advantages over visual interpretations resulting from the rapid quantitative identification of land resource categories and the immediate generation of summary statistics (Welch, et al., 1979). Automated analyses of Landsat data have been employed in several studies involving general land use (Dqrnbach and McKain, 1973; Welch, et al., 1979) and agricultural land use (Richardson, et al., be important in the study of regional relationships of both physical and cultural features (Thrower, 1970). 71977; Hanuschak, et al., 1979; Bauer, 1978). In the automated analysis of Landsat data, Draeger, et al. (1974) emphasized the importance of human-computer interaction, concluding that the most efficient and cost-effective method for producing "automated" surveys involves the use of manual interpretation at several stages of the process, particularly in the preliminary stratifications. Manual Analysis of Landsat Data The analysis of Landsat data by manual interpretation tech­ niques requires less specialized training and less expensive equip­ ment than automated procedures (Heller and Johnson, 1979). In addi­ tion, visual interpretation of Landsat imagery permits the rapid construction of regional and local map products (Welch, et al., 1979). Using a variety of techniques but emphasizing visual interpre­ tation methods, small scale land use maps of the northeastern por­ tion of the Plain of China and the Nun River Basin were produced from Landsat imagery.. To help identify crop types, aids including crop calendars, reflectance spectra and the use of images recorded on dates maximizing reflectance differences between crops were applied (Welch, et al:, 1979). Manual interpretation methods were also used to generate a land use map for the state of Iowa from Landsat imagery. The map was I ■ 8commercial/industrial., urban open, transportation networks, extrac­ tive land, agricultural land, forest, water, and reservoir flood. pools. Summer images were used since it was determined that they provided the most complete land use information (Anderson, 1977). Landsat color composite prints (a single photographic product produced by transmitting blue, green and red light through images of bands 4, 5 and 7 respectively) were interpreted visually and the data mapped directly onto an acetate overlay to produce a land use map of Boone County, Missouri. The interpreters used ancillary data including geologic, hydrologic, topographic, soils, road and pre­ vious land use maps in addition to familiarizing themselves with crop calendars, weather data and existing aerial photography. Using this methodology, maps with accuracies between 70 and 90 percent were easily and quickly generated (Elifrits, et al., 1978). The impending development of Wyoming's fuel reserves requires that a quick and efficient method of land resource inventory be employed to help manage the state's forthcoming growth; The use of . photo interpretive techniques for analyzing Landsat imagery were investigated in a preliminary study of Wyoming's Powder River Basin. Landsat data were able to provide much of the needed physiographic drawn at a scale of 1:250,000 and then printed at 1:500,000 and. includes nine categories of land use: Urban residential, urban 9and land use information more quickly and efficiently than conven­ tional inventory methods. Although Landsat imagery did not furnish the detail needed for some land use applications, it was found to be capable of providing a great deal of broad scale land use data on a continuing basis (Breckenridge, et al., 1973). Cropland inventories comparing 1:125,000 scale color infrared (CIR) high altitude photography and Landsat 1:1,000,000 scale (band 5) black and white imagery were conducted in Kern County, California. Inventories completed using imagery acquired on a single date re­ vealed no significant differences in accuracy between the two imagery sources. In terms of absolute accuracy though, the optimum results were^achieved by a multidate analysis of the Landsat imagery. This is significant in that even though the scale had been decreased and the resolution degraded compared to the 1:125,000 photography, the analysis of Landsat data achieved comparable results and in this study slightly higher absolute accuracy (98% vs. 97% accuracy) than the CIR photos. The availability of multidate Landsat scenes and the lower cost of Landsat imagery for an equivalent ground area give Landsat additional advantages over high altitude CIR photography. In any case, surveys completed from either high altitude CIR photos or Landsat imagery can be accomplished at 3% to 5% of the cost and in 95% less time than conventional cropland surveys (Jensen, et al., 1975). 10 The repetitive coverage of Landsat enables the interpreter to monitor changes in land resources over specific time periods. For California's San Joaquin Valley, photo interpretation of Landsat imagery was used to record land use changes during a one year period. The imagery proved adequate in monitoring and mapping macrolevel land use changes. However, it was determined that to achieve the best mapping accuracy the interpreters should be familiar with the areas1s landscape features and their geographic distribution (Estes, et al., 1974). To estimate irrigated acreage in a section of southwestern Idaho, Landsat false color composites were manually interpreted and the data recorded on a grid corresponding to a commonly used map base. Each map grid cell represented a ground equivalent area of 3.6 x 3.6 kilometers and the imagery was selected to match the time when the bulk of the irrigated crops were at maturity. Imagery covering a three year time span was chosen to determine the extent of irrigated cropland expansion during that period. The data was mapped at 1:1,000,000 and found to have a sampling error of 6-10%, an error rate quite acceptable for this type of survey (Heller and Johnson, 1979). A similar inventory of irrigated lands was completed for the Klamath River Basin of Oregon. For the inventory it was. necessary to use imagery from both mid-summer and late-summer to discriminate between irrigated and dry farmland. In July all irrigated fields appear red on the imagery.as do a few dryland areas. However* by September all dryland crops have matured and appear tan on the imagery while most of the irrigated lands still have a red appear­ ance. By comparing the images from the two dates the irrigated and dryland fields could be definitely separated (Draeger, et al., 1976). Place (1974) used manual interpretation of Landsat imagery in an attempt to map land use change in the Phoenix, Arizona area. Changes detected included conversion of crop and rangeland to resi­ dential development, desert to new cropland, and new reservoir fill-up. Land use change detection from interpretation of high . altitude U-2 plane photos was more detailed than the Landsat inter­ pretation but the total area and pattern of change were similar for both interpretations. An attempt to enhance change detection by overlaying images of different dates using different color filters proved ineffective. The primary differences shown by enhancement proved to be different stages of vegetative growth and not land use changes. Geographic Information Systems Using Remote Sensing Data Input The formulation of geographic information systems (GIS) has been a recent development in the management of land resource data. Such systems commonly contain data on soils, geology, vegetation, transportation, political units and other land related factors (Ford, 1978). Shelton and Estes (1979) discussed the need for the integration of geographic information systems with remotely sensed data. Hill-Rowley and Enslin (1979) noted that the incorporation of remotely sensed land cover information into regional computer grid systems should be a defined objective of regional planning agencies. New York State's LUNR (Land Use and Natural Resource Inventory) was one of the first systems developed that incorporated remotely sensed data on a large scale. Initiated in 1966 by. the Center for Aerial Photographic Studies at Cornell University, LUNR used visual interpretation of conventional black and white aerial photographs to compile a detailed inventory of land use and natural resources in New York. This information is stored on computer discs and products of the system include overlay maps of areal, point, or linear data; printouts listing information about each cell; and computer maps indicating the location of quantitative analyses performed on the data (Ford, 1978; Hardy and Shelton, 1970; Shelton and Tilman, 1978). Many geographic information systems are now using information derived from the interpretation of Landsat satellite imagery as a source of land resource data. In Minnesota, Landsat imagery has been applied to updating land use data for the Minnesota Land 12 13 Management Information System (Sizer, 1974). It was established that high quality Landsat images could yield more detailed land use data than previously existed for Minnesota (Brown, et al., 1973). The United States Geological Survey has tested the capability of Landsat as a source of environmental data for CARETS (Central Atlantic Regional Ecological Test Site), an.experimental regional environmental information system. Like LUNR, CARETS is a geographic information system with overlay capabilities for computer map pro­ duction. This system has been used in test studies to detect land use changes along the mid-Atlantic coast of the United States with favorable results (Alexander, 1973 and 1974). CRIES (Comprehensive Resource Inventory and Evaluation System), originated in 1975 by the United States Department of Agriculture and Michigan State University for estimating agricultural growth potential in developing countries, also employs Landsat data as a source of land use information. In the Dominican Republic manual interpretation of Landsat imagery proved to be accurate, practical, and more discriminating than computer classifications for inputs into CRIES. The use of manual techniques for interpreting Landsat imagery is also advantageous in that! the technology required for such interpretations is easily transferred to workers in developing areas (Shelton and Tilman, 1978). 14 Input of remotely sensed data into a GIS allows combination with other spatial resource data to aid in planning and zoning activities. Such an analysis was undertaken near the Black Hills of South Dakota where land use data from visually interpreted high altitude photography were composited with soils information to assist in land use decisions (Cox, 1977). Landsat data were added to a computer management system for a power plant siting study on the Delmarva (Delaware, Maryland and Virginia) Peninsula. The result was the production of computer drawn composite maps showing areas having acceptable land resource parameters for either nuclear or fossil fuel power plants (Halpern, et al., 1975). There are several advantages to computer processing of digi­ tized data contained within a geographic information system. Digi­ tal data are registered to geographic coordinates and stored in easily accessible form for overlay and monitoring capabilities. In some systems the planimeter task can be done by computer rather than by manual methods and spatial display of the data can be provided at the desired map scale by computer plotter. This eliminates the need for cartographic or photo lab renditions of the data including enlargements and reductions, making a variety of hardcopy products readily available (Cox, 1977). MATERIALS AND METHODS Manual interpretation of Landsat false color composite trans­ parencies was used to produce a land cover map for Montana at a scale of 1:1,000,000.. The thirty-five images needed for statewide coverage were selected based on percent cloud cover and acquisition during the growing season. The images were purchased from the Aerial Photography Field Office of the USDA-ASCS in Salt Lake City, Utah. A list of the images used is given in Appendix I. It was felt that cloud free imagery obtained during the growing season would be the most useful in identifying land cover. Therefore, only images from the months of May through September with cloud cover of 10 percent or less were chosen. The images used in this study range in date from 1972 to 1976. To produce the state land cover map each image was registered to rivers, lakes and other identifiable landmarks displayed on a translucent mylar base map at the 1:1,000,000 Albers Equal-Area Projection. The interpretations were done with the aid of a light table and transferred directly to a matte-finish mylar overlay registered to the base map. Classification of Land Cover The term land cover is preferred over land use since "use" carries the connotation of a specific activity being present. Such 16 activity may or may not be detectable on remote sensing imagery. Burley (1961) defined land cover as "the setting in which action takes place, i.e., the vegetation and artificial constructions covering the land surface." Seven categories of land cover were delineated in the production of the state land cover map: Irrigated crops, including irrigated pasture and subirrigated lands; dryland crops; forest; range; water; alpine and rock outcrops; and urban areas having a 1970 census population exceeding 20,000. Identification of Land Cover Types A number of factors were considered in identifying land cover categories. These included a landscape feature's color, texture, size, shape and its association with other features. The following sections describe in detail some of the factors considered in the interpretation of land cover types. Irrigated Crops Irrigated crops are often located in valley bottoms and along natural drainages in Montana. Since they have a high reflectance in the near infrared, irrigated crops are identified during the growing season oh the false color composite imagery by their bright red appearance. To avoid confusion with non-irrigated vegetation, imagery should correspond to dates after which noh-irrigated crops 17 have begun to ripen. On imagery acquired earlier, non-irrigated vegetation may resemble irrigated crops due to the continued presence of adequate soil moisture. Some irrigated land is readily identified. Such is the case with irrigated crops under center pivot irrigation systems which can be recognized by their distinctive circular shape. However, some land mapped as irrigated crops is associated with riparian and sub­ irrigated lands. Since it is difficult to distinguish between irrigated crops and riparian and subirrigated lands, no effort was made to separate them in areas where they were iinterspersed. Dryland Crops As explained in the previous section it is best to use imagery from the latter part of the growing season to avoid confusing dryland with irrigated crops. As dryland crops mature, their appearance on the color composite imagery changes from progressively lighter shades of fed, to pink and then to a whitish hue upon crop ripening. In addition to their color, the linear boundaries of many dryland crop fields aid in their identification. Strip-cropped areas can be readily recognized by their contrasting bands of cropped and fal­ lowed land. Areas under fallow at the time of image acquisition were included in the dryland crop classification. On the imagery, fallow areas appear from dark to light grayish blue-green depending 18 on the tillage techniques employed and the soil surface conditions. Fallowed areas containing stubble appear light brown to gray and may be difficult to distinguish from range cover, particularly where dryland crops, and dryland pasture are mixed. Forest Areas classified as forest consist of all identifiable coni­ ferous woodland areas. Forest areas, like other concentrations of vigorous vegetation, reflect highly in the near infrared giving them a red appearance on the Landsat imagery. In contrast to the bright red of irrigated crops, forest areas are represented by a darker red on the imagery. Other factors which may aid in the identification of coniferous forests include their granular appearance on the imagery and their irregular boundaries which often follow variations in aspect and topography. Water Reservoirs and lakes were classified as water on the land cover map. Clear water absorbs a large percentage of the incident electro­ magnetic radiation causing it to appear black on the imagery. With increasing turbidity the appearance of water changes from black to light blue. In mountainous areas, water bodies may be hard to iden­ tify because of the masking effects of shadows from the rough ter­ 19 rain. Generally, however, water bodies are easily identified and mapped from Landsat imagery. Urban Urban areas mapped include only those cities whose populations were greater than 20,000 at the 1970 census. Although visible on the imagery, smaller urban areas were not mapped due to their com­ paratively insignificant areas and the problems associated with their representation on a map of such small scale. The appearance of urban areas on Landsat imagery varies from red and flesh^colored tones to white and/or mottled blue patterns. Residential areas appear either flesh-colored or shades of red due to the integration of white tones produced by highly reflective objects such as roofs, sidewalks and streets, and red tones from the high near infrared reflectance of trees, lawns and other vigorous vegetation. Residential areas, especially low density residential areas, may be confused with dryland and irrigated crops in the spring. To avoid confusion it may be beneficial to use imagery taken later in the summer when residential vegetation begins to suffer from lack of moisture, mowing, and other stresses (Anderson, 1977). Due to the lack of vegetation and presence of highly reflective objects, main business and industrial areas are represented by white 20 to blueish tones on the imagery. Radiating out of the hub of the central business district is often a network of highways, blueish- gray in appearance, which may also serve as an aid in identifying urban centers. Alpine and Rock Outcrops The classification, alpine and rock outcrops, includes all land areas above the treeline and locations having sparse vegetation where rock outcrops predominate. The appearance of alpine areas differs in response to snow cover and vegetation condition. Snow is highly reflective, hence, snow-covered areas are white on the imagery. Snow-free alpine areas also may appear white where little vegetation is present and the area is dominated by light-colored rocks. Alpine areas having sufficient vegetation vary in appearance from pink to red depending on the conditions and quantity of the vegetation present. The appearance on the imagery of areas dominated by large out­ croppings of rock is dependent on the color of the rock. Light colored rock outcrops are highly reflective and are represented by light tones while less reflective rocks appear dark on the imagery. Range The range classification includes treeless areas below treeline dominated by grasses and/or shrubs, dryland pasture, and badland 21 areas. Range varies considerably in its spectral response depending on soil moisture conditions, vegetation condition, and other vege­ tation and soil influenced reflection properties. Range appears as shades of gray or gray-brown on the color composite imagery. To avoid confusion with irrigated or dryland crops, range is best depicted on imagery obtained in the latter part of summer. At this time the moisture stressed range vegetation is easily distinguished from the red color of healthy irrigated crops and the uniform pink to white response of ripening dryland crops. Encoding of the State land Cover Map A computerized geographic information system developed by Gary L. Ford is available.at Montana State University (Ford, 1978). Upon completion, the state land cover map was digitized and added to this system. This increased the number of maps presently stored in the system to seventeen. These maps include: 1. Soils 2. 1941-70 Average Annual Precipitation 3. 50 Year Peak Precipitation 4. Number of Strong Chinooks per 100.Years 5. Potential Evapotranspiration 6. Average Annual Effects of Erosive Rains 7. Average Length of Frost-Free Season 8. Average Date of First Freeze 9. Average Date of Last Freeze 10. Consumptive Use of Water 11; 1968-72 Average Annual Snowfall 12. Geology 13. Percent of Annual Precipitation Falling from April I thru July 31 22 14. Percent of Annual Precipitation Falling from May I Thru July 15. Climax Vegetation 16. Elevation 17. Land Cover Products of the system include both plotter-drawn maps and alpha-numeric line-printer maps. The system is capable of out- putting data from a single map or performing a joint analysis of several maps (i.e., soils, precipitation, length of growing season, etc.) to produce a composite map locating areas containing a par­ ticular set of environmental parameters. In order to be encoded into the system, a map must, first be prepared at a 1:1,000,000 scale with Albers Equal-Area projection. A plotter-drawn mylar grid at the same scale and projection is used to encode the map data. The grid is based on latitude and longitude and has an average cell size covering 21.3 square kilometers. The grid is overlain on the map and the data are coded for each cell by. the dominant category present. If no category is dominant then the class at the cell's center is encoded. The data is then recorded and keypunched and the resultant computer drawn map is checked for errors (Ford, 1978). Areal Tabulation of Land Cover Categories The encoded state land cover and general soils (USDA-SCS, 1978) maps were sent to the Remote.Sensing Institute at South Dakota State 23 University for conversion to AREAS (Area Resource Analysis Systems) for areal tabulations. AREAS is a computerized geocoded cellular information system. The output received from AREAS included a breakdown of the hectares of each soil mapping unit under a specific land cover (Appendix III). These data were then analyzed for soil- land cover relationships throughout Montana (Appendix IV). Testing Land Cover Map Accuracy Source of Ground Truth Data Due to the prohibitive expense and amount of time required for the collection of ground truth data by field observations, existing land use maps for eighteen Montana counties were used to check the land cover map accuracy. The maps were prepared by the Montana Statewide Cooperative Land Use Mapping Program, coordinated by the Department of Community Affairs, Helena, Montana, and the Yellowstone-Tongue Area Wide Planning Organization, Broadus, Montana. The Department of Community Affair's maps include: Broadwater, Carbon, Cascade, Deerlodge, Hill, Lewis and Clark, Mineral, Missoula, Park, Pondera, Silver Bqw and Teton Counties. Counties embodied by the Yellowstone-Tongue Area Wide Planning Organization maps are: Carter, Custer, Fallon, Powder River, and the northern portion of . 24 Rosebud County. The shaded areas of Figure I show where these counties are located in association with the remaining portion of the state. Selection of Ground Truth Sites Ground truth sites were chosen by a stratified random sampling of sections located within the described eighteen county area. To select each section, rapdom numbers corresponding to tier and range designations were computer generated to specify township and random numbers between I and 36 were generated to determine section. To locate each section oh the land cover map, a map of identical scale and projection displaying township locations was overlaid on the land cover map. Each specified section was then located with the aid of 16 lines per inch graph paper. Each cell on the graph paper closely approximates a section at a scale of 1:1,000,000 (I cell represents 0.99 square miles). The dominant land use within each section was then used to classify each sample site. The resulting classification was then checked for agreement with the classifi­ cation within the same section on the county land use maps. NJ Ln Figure I. Area covered by county land use maps used as ground truth (shaded regions) 26 The minimum number of sample sites needed to check each land cover category was determined by the following formula: 2 2 N = . L Where N is the minimum number of samples needed, 1.96 is the t-table 2 value for a confidence interval of .95, S is the estimated variance for a binomial distribution and L corresponds to the acceptable degree of error. Assuming a map accuracy of at least 80% with a .95 confidence interval yields: H (1.96)2(0.80)(0.20) _ 615 _ o.io2 To insure an adequate sample, a running total was kept for each category until 70 checks were performed on each classification. This figure is in excess of the minimum sample size of 50 recommended by Hay (1979) for sampling land use map classification accuracy. Exceptions to a sampling number of 70 are the water and urban classifications. Due to the difficulty in obtaining seventy random samples on the small relative area occupied by water in Montana, only 25 sample checks on the water classification were performed. It was felt that this number would be adequate, particularly since 27 surface waters are easily identified.on the satellite imagery. In addition, the selection of ground truth sites was not limited to the eighteen county area previously described. Instead, USGS topographic maps were used as ground truth so the sampling area for water could be expanded to include almost all of Montana. The insignificant area occupied by urban areas in Montana made sampling of these areas impractical. Therefore, no checks were performed on the urban cover classification. Upon completion of the sampling scheme, the overall classifi­ cation accuracy for all samples was calculated. In addition, the accuracy for each classification category was determined. RESULTS AND DISCUSSION Land Cover Distribution in Montana Figure 2 is a photo-reduced copy of the 1:1,000,000 Montana land cover map produced from manual interpretation of Landsat imagery. A 1:1,000,000 computer plotted version of the land cover map is presented as a map supplement to this thesis. The computer drawn map does not possess the detail of the original hand-drafted map but it still demonstrates general land cover distribution in Montana. The results of the AREAS program's tabulations of the areal extent of the seven land cover categories (Table 2). show range to be the dominant cover type in Montana. Range occupies approxi­ mately 50% (18,890,000 hectares) of Montana’s total land area and is found predominately in the eastern two-thirds of the state and in the intermontane valleys of the west. The largest extents of uninterupted rangeland occur in east central Montana where soils have developed on soft sandstones, siltstones and claystones. In this area, topography is locally rugged due to differential erosion between beds of softer and harder materials (Veseth and Montagne, 1980). Many of the soil associations having extensive range cover are located on these rough, dissected bedrock plains (Table 3). Significant acreages of rangeland also, occur on the glaciated till s KEY 'O' □ IRRIGATED CROPS □ DRYLAND CROPS ■ FOREST □ RANGE H ALPINE a ROCK OUTCROPS ■ URBAN (» 2 0 ,0 00 pop ) ■ WATER N) 4 Calclorthlds Nearly level to moderately steep terraces, fans, benches calcareous loamy alluvium ately deep to deep gi 6 2 92 - Crago, Williams Kf Calclorthlds, Arglborolls Moderately sloping to steeply sloping foothills alluvium deep I - 12 18 64 - Amesha, Crago, Evanston, Musselshell, Nuley Kt Camborthlds, Natrlarglds Nearly level to moderately steep lacustrine terraces lacustrine sedi­ ments, alluvium moder­ ately deep sic,slcl, 26 U - 63 - Lonepine, Ronan, Round Butte Lgl Cryochrepts, Eutroboralfs, Eutrochrepts Undulating to rolling foothills of valleys and glacial moraines clayey alluvium, clayey colluvium deep T I - 92 6 — Crow, Haugen, Inez, Lubrecht Trapps, Whltore, Wlnfall LgZ Cryoboralfs, Cryoborolla Undulating to rolling foothills of valleys. glacial till, alluvium, colluvium moder­ ately l.gl.cl - — 86 14 - Babb, Hanson, Loberg Lg3 Cryochrepts, Cryoboralfs Lt Cryochrepts, Cryorthents Ma Cryochrepts, Cryandepts Mel Cryochrepts, Cryoboralfs, Me2 Cryochrepts, Cryoboralfs glacial moraines Undulating to rolling foothllla of valleys, glacial moraines Nearly level outwash terraces Steep to very steeply sloping mountain slopes deep to deep colluvium g to atl - - 93 loess, ash cap over deep argillltic realdlum Moderately sloping to very Limestone, colluvli* deep steep mountain slopes various rock Moderately sloping to very steep mountain slope colluvium, metamor- deep phlc rock, sandstone ? ell,I gl,ell,si,I - gl,cl,etel, I Garlet, Worock 7 - No reference series 94 I 5 Buckhouse, Coerock, Felan, Holloway, Trueflssure 92 2 5 Crow, Gambler, Holloway, Loberg, Lubrecht, Trapps, Tropal, Whltore, Wlnfall, Worock 97 I I Garlet, Holloway, Loberg, Tenrag, Worock OO OO Table IV-I. (continued) Hap Symbol______ Great Groups Parent Material Soil Surface ___ Depth_____ Texture_____I % Land Cover D F R A Representative Me 3 Cryochrepts, Cryoboralfs, Cryoborolls Moderately sloping to very sedimentary rock, steep mountain slopes igneous rock, colluvium, glacial till deep I,SllVgl - 94 4 2 Adel, Elkner, Garlet, Sebud, Worock Me4 Cryochrepts, Cryoboralfs, Lithic Cryoborolls Moderately sloping to very colluvium, igneous steep mountain slopes rock, sedimentary rock shallow to deep I.Sll1Cl - 91 4 5 CheadIe, Duncom, Gambler, Garlet, Loberg, Whitore, Worock MeS Cryochrepts, Rock Outcrop Moderately sloping to very colluvium, alluvium steep mountain slopes deep siI, chan- nery I - - 83 - 17 Garlet, Whitore Mfl Crfochrepts, Ustochrepts, Eutroboralfs Moderately sloping to very colluvium, alluvium, steep mountain slopes calcareous rock material deep gl.sll.s+sl I - 96 2 .5 Crow, Garlet, Holloway, Macmeal, Repp, Trapps, Whitore, Winkler Mf2 Cryochrepts, Ustochrepts, Cryorthents Moderately sloping to very granite steep mountain slopes shallow to deep Sl1I1Sll I - 77 6 16 Ambrant, Elkern, Stecum Mf 3 Cryochrepts, Ustochrepts, Cryoboralfs Moderately sloping to sedimentary rock, steep mountain slopes glacial till deep gl.sll.l I - 90 3 7 Teton, Mollman, Repp, Trapper, Whltore Mf4 Cryochrepts, Ustochreptst Lithlc Cryoborolls Moderately sloping to mixtures of sedi- steep mountain slopes mentary, igneous, metamorphic rock shallow to deep gl.scsl - 96 4 Cheadle, Garlet, Winkler Mol Cryoborolls, Cryochrepts, Cryoboralfs Gently sloping to very ? steep mountain slopes deep T - - 71 27 - No reference pedons Mo 2 Cryoborolls, Cryochrepts, Ustochrepts Gently sloping to very alluviisn, colluvium, steep mountain slopes sedimentary rock moder­ ately deep to deep l.gl.sll - 76 23 I Hanson, Skaggs, Whiteco*:, Whltore 00 VO Table IV-I. (continued) Map Symbol Great Groups Landform Parent Material Soil Depth Surface Texture I % Land Cover D F R A Representative Soil Series Mo 3 Cryoborolle, Cryoboralfe, Cryochrepte Gently sloping to very steep mountain slopes colluvium, alluvium, igneous rock residuum deep l,gl,sll,g«l - - 89 11 - Bridger, Cowood, Ess, Garlet, Loberg, Teton, Horock MoA Cryochrepte, Cryoborolle, Haploborolla Gently sloping to very steep mountain slopes alluvium, igneous rock, sedimentary rock shallow 81.1 78 21 I Belain, Bridger, Castner, Cheadle, Cowood, Hanson, Libeg, Peraa, Tropal Mo 5 Cryoborolle Gently sloping to very steep mountain slopes shale, limestone shallow to deep • 11.C - 57 43 - Duncom, Mayflower, Tarrete Mo6 Eutroboralfe, Agriborolle1 Llthlc Cryoborolls Gently sloping to very steep mountain slopes alluvium, igneous rock deep all,I,cl - 74 26 - Cheadle, Farnuf, Hilger, MicmeaI, Yourame R Rock outcrop, Tallus, Cryoborolls, Cryochrepte Mountain peaks, gently sloping to very steep alpine grasslands alluvium, colluvium, glacial till, various rock types shallow to deep I,»11,»1.gel I 43 I 56 Blackleed, Cheadle, Cowood, Garlet, Raynesford, Sebud, Tropal, Whitore E t - j : m ' L l r £ T t C ; to S> * - ' f *• - >r. ,v V T x- ^ v- «, i - - - % I f 6 ' - Li" I - B m - .L. _ _. . 5? v fcft tr it) ■> «r»- #- -ft c ft s- »• I ■ u^ V — - -‘L ■’ »• I - t ,-n - • V - -X -f- :n - X- V X T» . 'J- n ■:<** {*, I: rt -xr tr •O' «r ■=' s— -'t <•! t f xr - ,m •'tJii a * Ar M »*r AL - m L- •#» ! IT vi» J - — ■- ■■ -■'- .... —J#% n - •? -. -o ST #, v '*»: rf: •»; ft [sr *? 9* v v- ^ ^ . r uI T ^ ’ >- - : - ; " ^ V *• L> OH ‘iX V - ' '•'- - 3 l^ . :■ - -,I . V- ! X\ W> j.>7 nr- jv r,. V !V - F i '•> i i *- *r ef rIF F F - * ' ^ H i ^ c / i -Ji 'XT' - X J X M -O f t XI tf) I--:-- I -:--- - ---- L-P V ' t ' t - $ & r _ - T l - < X- V V# •y> i* ro m a- XT xf V X- A V Xf- V r- - - —* i—— P t 5 • - -JX -o. IT m m m yi -ii> v - LtzAUi B T m , ; 'v :•' llU v F J U' Fi r v ■* ■'■ L XF »2 n j- x p ;w -» . —— -- -- 'SH v r ^ - j------— i' ;— —A — - -----------------------* I * * t , r. w -I ! ’ F C - , j r •- t; «- v f». i - — , [ ••- — i— i 1 — -- ^ i ; ^ ^ ^ y- ; ^ ^ k '-T- * > •.'■ , ^ f r , — r ' fVm ETETV L i L - V - - r . r _ " U r - J j Ti --"I. LpT ! R F -Li L -x. --___ _ ? J ’ - — □ IRG ATE * < u r Li "tT i 3". F - F - F j !FufT k?i 39926 F' • 'L ' M ox Of '. _. , fB— , --- >--- - r— r W 1Xi I x- re « >r "=• ♦•‘ ‘ *'•; - 1—‘ F ! ' T T P T 'i B E T U U „ . ‘ - : $ - ------^ : r~ •> rrj O •% SB ' .L S I T 'i L1 >.• i x* * Xf x» xr •; ... ., V •ti T m -) ^ m Znn- crt r. , x, -E B — - , " - r r • .— -V T--- I— r *— I * v h' -n k , i ■jtrfrr-i r 3 - B•9__7L_Lr-*" ' • 9 t • Lit •>{■_ r r> x- *i -7 <• iv> x r J -- : - '— — - ___ EL S d T -rI # <30 o- IT- -r "I CO — I 'T CL T IT >- to O T l : . T E iO- f^S I' ■ t«- _ ta E ' % Xv ^ , n; n U . .a , a u TL it, rt, •c- rx. I- x«- - L i u ; - - T E - L A 'O CO V* K ft Vj T- v ; " ,1V V V <-,■ -O :A ; i . J r - K^ j—- — PT' T JtT ZT J' T&i ---X-1 ------------:----J 1X: 'en A C»? T T E F : : • Li . iJl ; " ' i n y. * T =f V CM ^ ^ *0 n *r- (c Cf, ^ S J3• 9 i - ,--- »- U" L CO m CX r , T J Cl Cl TT " # L > B•9 *- . S r T Tl i . T - " jCrt r mJl dLB ES <*» (* A ? «5*1 CO r - v- ErT F ;liZp t T T T r EIrXtU- *1 * f» j i"1 10 ■»:■ <0 FT t ix K fS H H H iH 5. T- I Tuu " ' H H H H jL E fT i : PPT FDFEL “ / > I i T i iIvLT v / - M Z r? CA i Eg tr ! T tT i D m ,1 f th UrZ kJ> • 'rt ! ?f.X -jT-' v V F / Lv T ir- F ■ Es F -Z— ;— CO «■ x ; ? .6 73 m <0 CT - - j T ' 'E- X L - - I I PHHt- - C OP fc T•v 07 «r- T-S „S_____________ B i ro ” 1 TQ I-L jf i T _ _ A V v - F j. JTTl 1-------------— , - . . - - • -C : L - - J X " ■' ■ >« eg I - j J «r. M X i r - — T L F** *rt CO > A ISO v. 0 u> , I " ! ------------------ '- — •; L--------------—------- -- - : «>•••* r- n ' - - ^rf---1 ---- ; j— I ---- |«0 '0 ■> I of -r r f <* O "V L3 •rt f) #0 - '• rtrt rt (v> r) g i F 1 L X « . I rr FJ r_ JZf ffi L *■ L—«— rry ^ Trt rtt -------T Xf - X- --• - 11-t .. ~ X -Cl - --■ . n mu c_:r S i r t r I F X - C 1 F- -L ,.* -- — - i — ' '!O C » I " I f H H H l E LiE ,-0 * <« O ' R FiT ^ X .. ,- j Hf jJFp T ■ p*—i SEY EL . - S :i j R T c r X F . I C i -f S 7H e E T p‘ m B R X TP F Lu*. C NG n: -- i _ 0: Es a' '• K «-» -- — - _■ Iio -* » I - o 'T l T T ' CL XE X L n -r n I F T -> § ER mi «*• nO - A - A ■'. ri ;V , [ J T j Hi CA R- % iv L H F f T - a # r. X e -x—— -f— c"11 - L L_ a '•-: r L hfi L ir F7S F y s. . <• s»v ••*» -t# - U t 'C' A e r ■ 3 11 *# - S RFRX 3 if ■ v tr FV Xl 0 S ----------L ------ r—J A ^ IU I, rci tJt I tr tt w Sn T 1 J — ----------------------- LC Vrt -A -rt- *A Xj- r? m m *? A _______________f c : H f c J1 ES SB . FUrrT ' ", RiJT- a — 3 ' -T> -*> T A EMT NS f - (ra w Tf • VJ :,to Ifi D T f> ! i -------------------------- • r- " — f "I on x< -RT 0 z to X- I - ^ JrCf ■> AvJW tm a ^ * «" r L rt* A $f>" ?•» u> r* y, : 0 0 s E El STFru ---1 fi (*! ., R S T i L L J STTl XJl La S i - L j — .« ,----- • "X --C ------} I ^ =O *■ ] .-a to , % — - - R i i T i T B T x u -------------------------p • . - j — - 05 ,■» m v rt or, W A t - , _ V i -f* -V) .*> •*; JT.'_ ' a' 3 F r I ! X r t i - J T •-tv .rt' X TT LZ 1 Cf re e ------ 5 r*> ..» <*$ f I 'C1» m 1 V S ; p L 0 ' Rl I e