RICHARD S. WILLIAMS, JR. U. S. Geological Survey Reston, VA 22092 PHILIP G. HASELL, JR. ALBERT N. SELLMAN* Environmental Research Institute of Michigan Ann Arbor, MI 48107 HARRY W. SMEDES U. S. Geological Survey Denver, CO 80225 Thermographic Mosaic of Yellowstone National Park

Improved techniques in the preparation of thermographic mosaics will enable more widespread use of such mosaics in regional environmental studies.

and Optics Laboratory** teamed up to create INTRODUCTION the first aerial thermographic mosaic of Yel­ URING THE MONTH of April 1969, the lowstone National Park. The aerial thermog­ D U. S. Geological Survey (EROS Pro­ raphy was acquired by the MIAI scanner gram Office), Air Force Cambridge Research (Fisher et al. 1965) mounted in a U. S. Air

ABSTRACT: An uncontrolled thermographic mosaic, which covers most of the area ofYellowstone National Park, has been compiled. The recording of aerial thermographic data on videotape is estab­ lished as one ofthe prerequisites for the preparation ofmore accu­ rate mosaics. Post-mission processing of the videotape record can rectify the nadir line to a topographic map base, correct for v/h variations in adjacentflight lines, correctfor yaw distortions, rectify distortions caused by pitch, and rectify distortions produced by non-linearity ofthe side-wise scan. Installation ofa thermal infrared scanning radiometer in a gyrostabilized mount and post-mission pro­ cessing ofthe videotape record (principally rectification ofside-wise scan distortion) would yield a controlled, photogrammetrically ac­ curate thermographic mosaic. However, the techniques used in the preparation of the uncontrolled thermographic mosaic of Yel­ lowstone National Park can be immediately applied to the prepara­ tion ofregional thermographic mosaics, important to geologists and other scientists and engineers in studies ofgeothermal and volcanic areas, and to other types of environmental investigations such as pollution studies of large water bodies (e.g., harbors, estuaries, lakes, etc.), where a precise planimetric image is not critical.

Laboratories (Terrestrial Sciences Labora­ Force (AFCRL) JC-130ND "Hercules" air­ tory), and the University of Michigan's Insti­ craft with scanner operation by University of tute of Science and Technology (Infrared Michigan personnel. The survey was carried * Presently with the National Aeronautics and Space Administration, Goddard Space Flight ** Now a component of the Environmental Center, Greenbelt, MD 20771. Research Institute of Michigan. 1315 PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING, Vol. 42, No. 10, October 1976, pp. 1315-1324 1316 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1976

out during the night of9-1O April 1969, at an the associated aerial photographic surveys altitude of approximately 8,200 m (27,000 have provided the data for several geological feet), and required nearly 5 hours to com­ and geophysical investigations. McLerran plete. and Morgan (1965) published the first paper on aerial thermographic studies in the Park. SURVEY OBJECTIVES White and others (1968) briefly discussed There were four primary reasons for the their geophysical research on the geother­ aerial thermographic survey. First, a ther­ mal areas in the Park for eventual correlation mographic mosaic of Yellowstone National with aircraft remote sensor data; ofparticular Park would be useful to geological and interest to aerial thermographic studies is geophysical investigations by delineating their discussion of snowfall calorimetry. the areas of thermal emission (from hot White and Miller (1969) and White (1969) springs, geysers, etc.) throughout the Park pursued this latter work in mapping of low­ during a specific period in time. Second, the intensity geothermal anomalies in the Park. MIAI scanner had been modified for vid­ Christiansen (1968) has studied the mapping eotape recording (Miller and Roe, 1967); ofbedrock and unconsolidated deposits from . hence, post-survey rectification of the aerial aerial thermography (3-5 fLm) of the rhyolite thermography was possible. Third, the ser­ plateau ofYellowstone. Ofparticular interest vice ceiling ofthe C-130 aircraft [over 9,100 was Smedes' (1968) evaluation of aerial m (30,000 feet)] permitted a high-altitude aer­ thermography in the eastern and north­ ial thermographic survey of a geothermal central parts ofthe Park to study areas under­ area to be carried out-of great value in re­ lain by early Cenozoic volcanic rocks. connaissance surveys of geothermal areas in Smedes (1970) also studied enhancement remote areas or in areas of high relief. Fi­ techniques with various types of photog­ nally, the thermographic mosaic would raphy and imagery, including aerial ther­ complement the previously published radar mography. Waldrop (1969) studied the de­ mosaic*, the color aerial photographic tection of thick surficial deposits from aerial mosaic (Smedes, unpublished data**), the thermography (8- 14 fLm) ofthe northwestern Geologic Map of Yellowstone National Park part of the Park. Pierce (1968) published an (USGS, 1972a), and the Surficial Geologic evaluation of aerial thermography (3-5 fLm) Map of Yellowstone National Park (USGS, to studies of surficial geology in Yel­ 1972b). Since the aerial thermographic sur­ lowstone. Smedes (1971) used data from two vey was compted, ERTS-l (Landsat-I) thermal infrared scanners combined with imagery of Yellowstone National Park has multi-spectral scanner data to evaluate use­ also become available. A fall image (1123­ fulness of aerial thermography and multi­ 17414) and a summer image (1015-17404) spectral imagery alone in compiling maps of provide excellent views of the area and are terrain classes with computer-assisted useful for correlating features visible on the techniques. thermographic mosaic. For example, resolu­ Along with aerial thermographic remote tion of the Landsat imagery (~80 m) is sensing studies ofgeothermal areas, regional sufficient to show the hot spring deposits in geologic studies involving remote sensing the Lower Geyser Basin, an area of intense were also pursued (Smedes, 1969). Several thermal emission on the thermographic radar studies have been carried out begin­ mosaic. ning with Christiansen and others' (1966) preliminary analysis of radar imagery ofYel­ PREVIOUS SURVEYS lowstone. Prostka (1970) published a At least four previous aerial thermographic geologic analysis of the radar mosaic of the surveys have been made of parts of Yel­ entire Park. Richmond (1970) studied the lowstone National Park, beginning in 1961 geologic significance of anomalies recorded (Table 1). on like- and cross-polarized, k-band, radar These aerial thermographic surveys and imagery of Yellowstone. Keefer (1968) evaluated the radar and infrared imagery of sedimentary rocks in south-central Yel­ * The Radar Mosaic (uncontrolled) of Yel­ lowstone. In addition, conventional geologic lowstone National Park (1968) is available from the EROS Data Center, Sioux Falls, South Dakota mapping (bedrock and surficial geology) was 57198 by reference to accession no. E-16-2430BN. also carried out in the Park (U.S. Geological ** Copies of the color aerial photographic Survey, 1972a and 1972b), partly in support mosaic are available from the EROS Data Center, of the airborne remote sensing studies and Sioux Falls, South Dakota 57198, by reference to for use with imagery from the Landsat-l accession no. E-415-45CT. satellite. Smedes (1976) has recently THERMOGRAPHIC MOSAIC OF YELLOWSTONE NATIONAL PARK 1317

TABLE 1. KNOWN AERIAL THERMOGRAPHIC SURVEYS OF YELLOWSTONE NATIONAL PARK. Areas Date(s) Organizations Type of Scanning Surveyed of Survey Involved Radiometer Selected Areas 20-22 Apr. 61 Univ. of Mich.l U.S. Army HRB-Singer D2 Cold Regions Research and Engineering Lab. Most of Park 13-15 Aug. 66 U.S. GeoI. Survey/HRB RECONOFAX IV Singer, Inc. Selected Areas 20-21 Sept. 66 U.S. GeoI. Survey/HRB RECONOFAXIV Singer, Inc. Geyser Basins and Parts of 19-22 Sept. 67 U.S. GeoI. Survey/Univ. of M5 Multispectral Yellowstone Lake, Yellowstone Michigan River, and Lamar River Most of Park 9-10 Apr. 69 Air Force Cambridge Res. MIAI Labs.lU.S. Geol. Surveyl Univ. of Michigan

2 completed a land-use planning study of the km ) or about 85 per cent of the area of Yel­ Park from Landsat-l imagery. lowstone National Park. In three instances there was insufficient side-lap to yield a AERIAL THERMOGRAPHIC MOSAICS complete coverage mosaic, thereby produc­ Generally speaking, the interpretation of ing gaps in the coverage. The east-west di­ aerial thermography (Williams, 1972) in mension is quite close to scale while the geological investigations is easier to ac­ north-south dimension is "stretched" by ap­ complish and is more comprehensive if the proximately 9 per cent. Additional process­ individual thermographs can be compiled ing could minimize this latter distortion. into an areal "map" or mosaic (Williams and The mean survey time was just after mid­ Ory, 1967). This is because many types of night (0022 hours) on 9-10 April 1969, and geological phenomena encompass areas except for minor cloud cover over the larger than can be imaged on a single ther­ southwest end of Shoshone Lake and over mograph (or photograph, for that matter) the southeast arm of Yellowstone Lake, the (Stingelin, 1969). Since the output of most mosaic discloses the unobscured surface top­ current scanning devices for producing aer­ ography and hydrographic systems quite ial thermographs are "strip maps" which well. The relatively high water temperatures are subject to geometric distortion, the com­ associated with thermal activity display pilation of a geometrically accurate thermo­ springs, rivers, and lakes as distinct "white" graphic mosaic is a difficult task. The ther­ targets on the black-and-white mosaic. mographic mosaic of Yellowstone National The mosaic was constructed from film im­ Park is presented as a typical mosaic made ages produced by playback of the scanner from separate film strips produced in 13 suc­ data recorded on magnetic tape during the cessive passes over the area. A few aspects of flight. The tape signals are used to intensity­ the geologic information recorded on the modulate a cathode ray tube (CRT) sweep­ thermographic mosaic are described along signal which exposes strip film. The CRT with its imperfections and the sources ofthe sweep and the drive speed of the film strip imperfections. are correlated with the airborne line-scan rate, the aircraft ground speed, and the flight THERMOGRAPHIC MOSAIC altitude above terrain to provide proper image scaling onto the film. The resulting Figure 1* is the completed mosaic, cover­ film strip is a negative transparency from ing approximately 3,000 square miles (7,770 which a positive paper print is made for as­ sembly into the mosaic. Ideally the strips will have sufficient * The Thermographic Mosaic of Yellowstone National Park, Wyoming, Idaho, and Montana, is side-lap to allow only the center portion of available from the EROS Data Center, Sioux each line to be used in the mosaic, where Falls, South Dakota 57198 by reference to acces­ "across-track" distortion is at a minimum sion no. E-17-2235BN. (Williams and Ory, 1967). The "along-track" 1318 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1976

10 KM

FIG.!. Aerial thermographic mosaic of Yellowstone National Park, Wyoming, Idaho, Montana. Mosaic was assembled from the videotape record of 13 individual thermographs. [9-10 April 1969, 0022 hrs. (mid-point of4 hrs. 48 min. survey), 27,000 ft. (8,200 m) alt. or 18,000 ft. (5,500 m) above ave. terrain), inSb (unfiltered), approximate original scale, 1:180,000). Air Force Cambridge Research Laboratories thermograph. and "across-track" scaling should be equiva­ pendent upon both altitude above terrain lent. Since the instrument normally has a and the aircraft velocity relative to the fixed "across-track" field-of-view (FOV), the ground track. "across-track" scaling is a direct function of Fortunately, variations in "along-track" altitude. The "along-track" scaling is de- and "across-track" scaling can be corrected THERMOGRAPHIC MOSAIC OF YELLOWSTONE NATIONAL PARK 1319 during film strip reproduction from tape mosaic. These illustrate, in part, the capabil­ playback. Figure 2 shows sections of two ity of "along-track" scaling corrections dur­ strips of the same flight line over Turbid ing tape playback. Strip A is a print of the Lake, located to the right-of-center in the full first film strip produced from the flight tape

N

o o

FERN LAKE

WHITE LAKE

TURBID LAKE

FIG. 2. Aerial thermographs of" the Turbid Lake area (kidney-shaped lake north of Yellowstone Lake and east of Yellowstone River), Yellowstone Na­ tional Park, Wyoming, showing original playback of videotape record (A) [original nadir line scale, approx. 1:340,000] and"stretched" playback ofvid­ eotape record (B) [original nadir line scale, approx. 1:282,000]; [10 April 1969, 0030 hrs., 27,000 ft. (8,200 m) alt., InSb (unfiltered)]; Air Force Cambridge Research Laboratories thermograph. 1320 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1976

by using flight-recorded aircraft altitude and extent and nature of the structural control of ground speed. Strip B is the second print bedrock on topography, particularly on the "stretched" to conform to the mosaic scale as geometry of the drainage pattern, are well determined by recognition of terrain fea­ shown. tures. Strip B was produced by increasing Many ofthe prominent physiographic fea­ the speed at which the film passes in front of tures of the Park can be delineated on the the modulated CRT sweep signal, producing thermographic mosaic because of distinct a longer film strip for the same time period of topographic expression and drainage tex­ tape data. Thus, on a trial and error basis, ture. For example, the texture of erosional each strip length could be increased or de­ dissection of the Absaroka Range (Eocene creased to fit a uniform scale. Of course, volcanics) is markedly different from that of when both the aircraft altitude above terrain the other mountain areas. The rhyolite and ground speed are known accurately in plateau, extending roughly from the Yel­ the first place, the scaling can be adjusted lowstone River southwest to beyond Upper properly in the initial playback. Herein lies Geyser Basin and Shoshone Lake, and the the major limitation in using line-scan de­ main central lowlands can be distinguished. vices to create mosaic area maps-the pre­ The young faults and fracture patterns in cise location on the terrain surface and direc­ the Amethyst Mountain area and those due tion and rate of scan motion of the instan­ to resurgent doming of the caldera floors in taneous small FOV ofthe line scanner is dif­ the area between Elephant Back Mountain ficult to determine. Once this information is and northwest of Sulphur Hills and in the known, however, it is relatively easy to pro­ Mallard Lake area east of Upper Geyser duce accurate scaling in film strip reproduc­ Basin are clearly shown. These faults and tions. Conventional aerial photography does fractures are shown on the geologic map not have this same limitation because, in ef­ (U.S. Geological Survey, 1972a), but analysis fect, the film is made up of many small de­ of the thermographic mosaic suggests that tectors which register a large area of terrain more faults exist than were mapped in the in the same instant. Variations in aircraft al­ area northwest of the West Thumb Geyser titude will result in photos ofdifferent scale; Basin, thereby forming a linkage between scale may vary within a photo, depending on the Elephant Back Mountain and Mallard local relief. Inaccuracies in aircraft altitude, Lake areas. attitude, and ground speed also affect the The arcuate flow-folds of the rhyolitic amount of overlap between successive lavas in the southwest corner of the thermo­ frames. In compiling aerial photographic graphic mosaic (Bechler River area) are prom­ mosaics, however, side-lap fitting ofadjacent Inent. Glacially-scoured arcuate northwest­ frames can pose a problem because of radial trending grooves and ridges on Mount distortion of terrain features when photo­ Everts are visible. The northwest-trending graphed from a different camera position. fault scarp complex north of Gardiner, and the sedimentary layers on Cinnabar Moun­ GENERAL DISTRIBUTION OF GEOTHERMAL tain (northern edge of the thermographic EMISSION mosaic) are extremely clear. Figure 3 (modified from Figure 5 in War­ The north-south-trending faults of Mount ing, 1965, p. 15) is a sketch map of Yel­ Sepulcher can be delineated. Northerly­ lowstone National Park showing geographic tending faults of the Mount Washburn area features and the location ofprincipal thermal are generally well shown. Those fa\!lts to the springs, geysers, and mud pools. (For addi­ west, but to the east of Roaring Mountain tional general information ofthe geology and and Norris Geyser Basin, are less prominent geothermal areas of the Park, see the excel­ than a probable northeast-trending set of lent booklet by Keefer, 1971.) The scale of faults which is strongly suggested by the Waring's map (Figure 3) is equal to that of thermographic mosaic. This latter set of the thermographic mosaic (Figure 1); hence, faults does not appear on geologic maps. the information content can be readily com­ It is important to note that some geological pared. Considerable hydrogeologic, particu­ information was lost in the specially­ larly geothermal, information has been re­ processed thermographs used to compile the corded on the aerial thermography. Unfortu­ mosaic when compared with the direct­ nately, essentially no direct surficial (USGS, record thermographs. The direct-record 1972b) or bedrock (USGS, 1972a) geologic thermographs seemed to have higher detail information is provided because ofthe deep in many areas and, in some cases, surveyed a snow which mantled the Park at the time of slightly different area. Ice-fracture patterns the survey-early April 1969. However, the were visible on the direct-record thermo-' THERMOGRAPHIC MOSAIC OF YELLOWSTONE NATIONAL PARK 1321

Ill' 110'30' 110' Clnnablir Mtn X

... \ ,

J I I \ (

I C"'"•• :\ k ' ?J' Saddle Mt~ ,/ ~-l ~-'

44'3O'1-1--1--'P'''''''===1

, '" :z: - 38. °IZ-< ;:Il -,>-Q,O I~ 39 40 41 ,I I, I .Grand

.-f}:"~,f04 ~:~~r;~~p GIantess ----l.I_ South entrance Castle. Ritlt'" ~ M~let 10 20 MILES Beehive -• '--'---'-~L--'--'-' -J' ..Cliff; Whistle • Rainbow Pool 10 20 KILOMETERS Oki Faithful. '--'~~~.-J' --.J. BIKk s.nd e...in HOTEL • ..... "omUS.c..o -Emerald Pool FIG. 3. Sketch map ofYellowstone National Park showing geographic features and principal areas of hot springs. (Modified from Figure 5 in Waring, 1965, p. 15.) (Original scale of Waring sketch map is 1:750,000.)

graphs, but not on the specially-processed than is usual for such surveys, although simi­ thermographs. This variation in thermo­ lar survey altitudes were employed during graphs is probably the result of different elec­ the aerial thermographic surveys of Iceland tronic settings for each version. After all, the (Friedman et al. 1969). The flying altitude primary objective was to produce a thermo­ was necessary not only to complete the graphic mosaic of a large area, not to optimize survey in one mission but also to provide a the thermographic mosaic for geologic in­ synoptic or regional display of geothermal formation. With appropriate electronic set­ activity-as opposed to low-altitude surveys tings, the thermograph used to compile the of a local geothermal area. Of course, the thermographic mosaics could be made simi­ "resolution" possible from such a survey al­ lar to the direct-record thermographs. titude prevents the depiction of very small From a geological viewpoint, the survey geothermal features in an area of intense altitude was far higher (8,200 m a.m.s.!.) geothermal activity (e.g., Lower Geyser Ba- 1322 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1976 sin). Many separate points (e.g., mudpots, thermal emission shown on the thermo­ geysers) or areas (e.g., steaming ground) of graphic mosaic which are not shown on either geothermal activity merge into a diffuse area the 1:125,000 or 1:62,500 scale maps. Exam­ of geothermal emission. ples of this, besides the areas previously Because of the snow cover and the frozen noted, are hot springs discharging into the lakes, geothermal areas and areas affected by southern shore of Shoshone Lake (to the left discharge of hot water (e.g., streams and of the mouth of Moose Creek) and on the lakes) stand out sharply on the aerial ther­ north shore of Lewis Lake, just west of the mographic mosaic as areas of white tone. mouth of Lewis River. Near the bottom of Figure 2, Turbid Lake is shown as ice-free, the result of hot springs CONCLUSIONS discharging into the lake from the south, or possibly caused by submarine hot spring ac­ CONSIDERATIONS FOR THERMOGRAPHS tivity. Tern Lake to the north appears to have To produce useful thermographs from ice on the southern margin of the west lobe line-scan devices, the following provisions of the lake but is ice-free to the north. An must be made in the production of imagery: area of intense geothermal emission is (1) Either the line-scan device must be shown south of White Lake, although it is stabilized about three axes in the aircraft or not cited by Waring (1965)' or depicted on the instrument motion about these axes must either the 1:125,000 (USGS, 1961) or be recorded on tape along with the video 1:62,500 (USGS, 1959) topographic maps of signal for stabilization of imagery during the area; however Smedes (1968) plotted its film strip reproduction. Traditionally, as in position on Figures 10 and 12 of that report. the Yellowstone mosaic, only motion about The Hot Spring Basin Group in the center of the aircraft roll axis is accounted for in imag­ the thermograph (Figure 2) is well de­ ery reproduction, but stabilization about the lineated, but again neither the sketch map other two axes is also relatively easy to ac­ (Figure 3) nor the 1: 125,000 topographic complish. map shows the full extent of the geothermal (2) The average aircraft altitude above ter­ area, particularly its southwestern extent to rain and in particular the aircraft ground the west of Shallow Creek (Canyon Village, track and speed must be known accurately 15-minute Quadrangle Map, 1959). both to fly the mission and to reproduce the From a qualitative viewpoint, the largest data. Otherwise, insufficient overlap will area of intense thermal emission on the en­ exist between successive flight lines and the tire thermograph is the area north of Yel­ scaling will be inaccurate. In the absence of lowstone Lake, an area of hot springs on the accurate navigational systems in the aircraft, southern part ofSulphur Hills. The main hot ground markers at known locations can be springs areas, such as Upper and Lower used to guide the aircraft and to scale the Geyser Basins, Norris Geyser Basin, etc., are imagery. well delineated by the distribution of (3) The imagery must be rectified in the numerous points of thermal emission and film reproduction to correct for the varying large areas of warm or steaming ground. path length between the aircraft and the ter­ Several points of thermal emission are qual­ rain surface along the scan line. This rec­ itatively "hot" compared to other areas in tilinearization amounts to producing an ap­ the Park. propriately nonlinear scan rate either in the Of interest in hydrogeological studies are scanning device or in the sweep ofthe CTR the tonal changes which take place along the printer. This type of imagery distortion was courses of the many rivers and streams in not removed from the Yellowstone mosaic Yellowstone National Park. Firehole River, and is usually minimized by using only the which traverses both the Upper and Lower central portion of the strip imagery, where Geyser Basins to the confluence ofthe Gib­ the distortion is minimal. bon and the Madison Rivers, and Yel­ (4) The radiation response ofthe line-scan lowstone River are excellent examples. Yel­ device must be constant as a function ofscan lowstone River shows a marked tonal change angle. It is preferable that the response be along its course to Yellowstone Lake. The the same throughout the scan, but at least it reason for the tonal changes is the addition must be constant and known so that it can be of warm (or hot) water to the rivers or accounted for in the film strip reproduction. streams from surface runoff from hot springs The scanner response was neither known or from warm groundwater discharging into nor accounted for in the reproduction. In this streams and rivers. particular imagery this radiation distortion Finally, there are many points or areas of appears as an average film tone change a- THERMOGRAPHIC MOSAIC OF YELLOWSTONE NATIONAL PARK 1323 cross the film strip, commonly referred to as as a source ofinformation in compiling maps "humping" ofthe signal. More sophisticated of geothermal areas. electronic processing techniques could REFERENCES minimize this undesirable tone variation within each of the image strips. Christiansen, R. L., 1968, A distinction between bedrock and unconsolidated deposits on 3-5J.L RECOMMENDATIONS infrared imagery of the Yellowstone rhyolite plateau: U. S. Geological Survey Tech. Ltr., It is interesting to note that with relatively NASA-104, 7 p. minor modifications and additions to line­ Christiansen, R. L., K. L. Pierce, H. J. Prostka, and scan devices, they can be used to produce E. T. Ruppel, 1966, Preliminary evaluation of thermographs relatively free of geometric radar imagery of Yellowstone Park, Wyom­ distortion. Electronic modifications to im­ ing: U. S. Geological Survey Tech. Ltr., prove image quality amount to: (1) removing NASA-30, 16 p. sources of stray radiation from the line-scan Fisher, D. F., George England, and D. S. Fisher, devices so as to establish their predictable 1965, Airborne infrared scanning system response as a function ofscan angle; and (2) M1Al: Univ. of Mich. Rpt. No. 6517-1-F, for restoring the low-frequency components of the Terrestrial Sciences Laboratory, Air Force the video signal for recording on magnetic Cambridge Research Laboratories, Bedford, tape. Geometric improvement in the images Mass., 92 p. can be attained by the provision of a three­ Friedman, J. D., R. S. Williams, Jr., G. PaImason, axis stabilized reference source on the scan­ and C. D., Miller, 1969, Infrared surveys in ning device and recording the motion about Iceland in 1966: in Geological Survey Re­ search 1969, U.S. Geol. Surv. Prof. Paper these axes on magnetic tape along with the 650-C, p. C89-ClO6. video signal and· scanner synchronization. Keefer, W. R., 1968, Evaluation of radar and in­ This information can then be used in a film frared imagery of sedimentary rock terrain, strip printer to produce distortion-free im­ south-central Yellowstone National Park, ages. With proper provisions, the CRT U. S. Geological Survey Tech. Ltr., NASA­ sweep can correct for aircraft motion and rec­ 106,12 p. tilinearization of the imagery. The CRT in­ Keefer, W. R., 1971, The geologic story of Yel­ tensity control can correct for non-linearities lowstone National Park: U. S. Geol. Surv. in response as a function of scan angle. The Bull. 1347, 92 p. film drive for the film-strip printer can be McLerran, J. H., and J. O. Morgan, 1965, Thermal correlated with aircraft altitude and ground mapping of Yellowstone National Park: in speed to produce image scaling. These pro­ Proc. Third Symp. of Remote Sensing of En­ visions are all technically feasible, but they vironment, Univ. of Mich., Ann Arbor, Mich., are not being done because ofthe infrequent Feb., 1965, p. 517-530. demand at present for mosaic maps made up Miller, C. D., and C. L. Roe, 1967, Tape recording from line-scan imagery. However, without system for use with the M1Al infrared scan­ ning system: Univ. of Mich. Rpt. No. 8435-6­ bothering to remove any image distortion, T, for the Terrestrial Sciences Laboratory, Air useful thermographs can be produced from Force Cambridge Research Laboratories, line-scan devices if patience and skill are Bedford, Mass., 31 p. used on a trial-and-error basis to fit the im­ Pierce, K. L., 1968, Evaluation of infrared imag­ ages into a mosaic. ery applications to studies of surficial From a scientific viewpoint, rectified geology-Yellowstone Park: U. S. Geological thermographic mosaics can provide valuable Survey Tech. Ltr., NASA-93, 35 p. information to geologists, because a mosaic Prostka, H. J., 1970, Geologic interpretation of a shows the relative size and qualitative ther­ radar mosaic of Yellowstone National Park: mal emission from geothermal areas. In the U. S. Geological Survey Interagency Report, case of Yellowstone National Park, the top­ NASA-179, 16 p. ographic map shows "size" of geothermal Richmond, G. M., 1970, Geologic evaluation of anomalies between like-polarized and cross­ area only in a schematic way by distribution polarized k-band side-looking radar imagery and number of small blue circles and by ofYellowstone National Park: U. S. Geologi­ printing the names ofthe springs in different cal Survey Interagency Report, NASA-165, 24 style and size of type face. When depicting p. hot springs on a topographic map, considera­ Smedes, H. W., 1968, Geological evaluation ofin­ tion should be given to overprinting the map frared imagery, eastern part of Yellowstone with a specific color to show actual areas of National Park, Wyoming and Montana: U. S. geothermal emission. The distribution and Geological Survey Tech. Ltr., NASA-83, 46 p. occurrence of hot springs are depicted on aer­ Smedes, H. W., 1969, Program statement for re­ ial thermographs. Such data could be used gional geologic studies in remote sensing, Yel- 1324 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1976

lowstone National Park: in Earth Resources map of Yellowstone National Park: Misc. Aircraft Program Status Review, NASA Rept., Geoi. Inv. Map 1-710. v. 1, p. 15-1-15-9. Waring, G. A., 1965, Thermal springs of the Un­ Smedes, H. W., 1970, Geologic studies of Yel­ ited States and other countries ofthe world-a lowstone National Park imagery using an summary: U. S. Geol. Survey Prof. Paper 492, electronic image enhancement system: U. S. Revised by R. R. Blankenship and R. Bentall, Geological Survey Interagency Report, 383 p. NASA-181, 24 p. Waldrop, H. A., 1969, Detection ofthick surficial Smedes, H. W., 1971, Automatic computer map­ deposits on 8-14 p,m infrared imagery of the ping of terrain: Internat. Workshop on Earth Madison Plateau, Yellowstone National Park: Resources Survey Systems, National U. S. Geological Survey Interagency Report, Aeronautics and Space Administration, Proc., NASA-166, 8 p. v. 2, p. 345-406. White, D. E., 1969, Rapid heat flow surveying of Smedes, H. W., 1976, Land-use planning in geothermal areas, utilizing individual snow Yellowstone National Park, Wyoming, Mon­ falls as calorimeters:}our. ofGeophys. Res., v. tana, and Idaho: in ERTS-l, A new window 74, no. 22, p. 5191-5201. on our planet, U. S. Geol. Surv. Prof. Paper White, D. E., and L. D. Miller, 1969, Geothermal 929, p. 310-315. infrared anomalies of low intensity, Yel­ Stingelin, R. W., 1969, Operational airborne ther­ lowstone National Park: in Earth Resources mal imaging surveys: Geophysics, v. 34, no. 5, Aircraft Program Status Review, NASA Rpt., p.760-771. v. 1, p. 16-1-16-4. U. S. Geological Survey, 1959, Topographic Map White, D. E., R. O. Fournier, L. J. P. Muller, and of the Canyon Village Quadrangle: 15-min. L. H. Truesdale, 1968, Geothemwl studies of series, 1:62,500. Yellowstone National Park (Test Site 11), Wyoming: USGS Tech. Ltr., NASA-109, 11 p. U. S. Geological Survey, 1961, Topographic map Williams, R. S., Jr., 1972, Thermography: Photo­ of Yellowstone National Park, Wyo.-Mont.­ grammetric Engineering, v. 38, no. 9, p. 881­ Idaho: Spec. Map, 1:125,000. 883. U. S. Geological Survey, 1972a, Geologic map of Williams, R. S., Jr., and T. R. Ory, 1967, Infrared Yellowstone National Park: Misc. Geol. Inv. imagery mosaics for geological investigations: Map 1-711. Photogrammetric Engineering, v. 33, no. 12, U. S. Geological Survey, 1972b, Surficial geologic p. 1377-1380.

Articles for Next Month

Dr. Marshall B. Faintich, Digital Sensor Simulation. Morton Keller, Analytic Aerotriangulation Utilizing Skylab Earth Terrain Camera (S-190B) Photography. Robert W. Pease and David A. Nichols, Constructing Energy Maps from Remotely Sensed Imagery. Alan D. Jones, Photographic Data Extraction from LANDSAT Images. C. J. Tucker and E. L. Maxwell, Sensor Design for Monitoring Vegetation Canopies. Charles W. Welby, LANDSAT-l Imagery for Geologic Evaluation. Richard D. Worsfold, Color Compensating Filters with Infrared Film.