EOSAT FAST FORMAT DOCUMENT FOR THEMATIC MAPPER (TM) DIGITAL PRODUCTS VERSION B, EFFECTIVE DECEMBER 1, 1993 GENERAL FORMAT RULES: 1. All field definitions strictly follow American National Standards Institute (ANSI) and International Organization for Standardization (ISO) standards. 2. Only Band Sequential (BSQ) image structure is supported because data to be written to the media is made available a single band at a time. (Geometric corrections to the image are done one band at a time.) 3. Image files consist of a single band of data. 4. A digital product is referred to as a volume set. Individual media types are referred to as volumes. A volume set may have one or more volumes, depending on image size and output media density. Multi-resolution data sets have a volume set for each resolution. 5. Fields that are not filled do not apply to the image data. GENERAL FORMAT DESCRIPTION The Fast Format volume set contains a header file, image files, and now a trailer file. The contents and format of the header and image files have not changed. The trailer file provides additional information about the image data. Current ingest software can read the header and image files. Ingest software modification may be required to read the trailer file. HEADER FILE The first file on each volume, a Read-Me-First file, contains header data. It is in American Standard Code for Information Interchange (ASCII), to ANSI and ISO standards. Alphanumeric fields are left justified and numeric fields are right justified. Dates are given in ANSI full year, month, and day-of-month format. All processing options and map projection information for the product are also contained in this file. IMAGE FILES All image files contain only one TM band of image pixels. There are no header records within the image file, nor are there prefix and/or suffix data in the individual image records. TRAILER FILE The last volume of the Fast Format image set includes a trailer file. This file may require software modification to read, but does not need to be read to ingest the image files. The trailer file contains ephemeris information to compute the approximate spacecraft position for each pixel in the image. This file is in ASCII, to ANSI and ISO standards. For information about the current content of the trailer file refer to EOSAT's Fast Format Trailer File Document. NOTE: EOSAT will use the trailer file to test the utility of new fields for customer use. Users should code the ingest of this file carefully because other data may be added to future versions of the trailer file. We recommend that you follow a procedure similar to: 1) Read the line as an 80 character ASCII string. 2) Decode the first few characters and test against expected entries. 3) Continue to read and decode if the first characters match the expected entry, otherwise print the line for visual interpretation. 4) Terminate on the characters END OF TRAILER FILE. The file is in ASCII and is readable as whole, and printable using standard system command utilities. Some users may prefer to "dump" the trailer file and print it using standard command language operations and therefore will not need to write new code. DETAILED FORMAT DESCRIPTION HEADER FILES The header file contains a single 1536-byte ASCII record. The accompanying table describes its format, including the number of bytes, the FORTRAN format statement and a brief description of each field in the header file. All alphanumerics are left justified, and all numerics right justified. Fields of fixed (constant) values are represented with capital letters in quotes (e.g., "PRODUCT ="). Variable fields are represented with lower case letters. Fields 35, 37, 39, 61, 95, 97, and 99 of each volume's header file must be read in order to import the image data. These fields are volume specific and must be read for each volume of a set. Fields 41, 43, 47, and 63-93 contain information necessary to convert from image coordinates to map projection and geodetic (latitude and longitude) coordinates. Field 10 (bytes 90-93) identifies the Thematic Mapper (TM) instrument mode and multiplexer where mode 1 = bands 1,2,3,4,5,6,7. Fields 21-33 (bytes 301-401) contain the maximum and minimum detected radiance levels within the scene for the corresponding bands present on the current volume. (See Field 95 to identify which bands are present on the current volume.) The maximum and minimum radiance values are in radiance units: milliwatts/(square cm-steradian). The nominal maximum and minimum radiance values for each satellite are included in Table 1. These values can be used to calculate the gains and biases to convert the image digital counts to in-band spectral radiance values. To obtain gains and biases, use the following equation: Gain = (Maximum Radiance /254) - (Minimum Radiance/255) Bias = Minimum Radiance Table 1 Radiance Values for Landsat 4 and 5 in milliwatts/(square cm-steradian) Landsat 4 Landsat 5 Maximum Minimum Maximum Minimum 1.104547 -0.022181 Band 1 1.059476 -0.016946 2.455621 -0.049292 Band 2 2.611919 -0.041805 1.402240 -0.033929 Band 3 1.639662 -0.026226 3.128049 -0.128175 Band 4 2.949823 -0.059251 0.643351 -0.015569 Band 5 0.683888 -0.016548 1.568660 0.125240 Band 6 1.524310 0.123780 0.457179 -0.009181 Band 7 0.424707 -0.008528 Table 2 Bandwidths for Landsat 4 and 5 in microns Band 1 Band 2 Band 3 Band 4 Band 5 Band 6 Band 7 Landsat 4 0.066 0.081 0.069 0.129 0.216 1.000 0.250 Landsat 5 0.066 0.082 0.067 0.128 0.217 1.000 0.252 Note: These calculated Gain and Bias values will give in-band spectral radiance values in units of milliwatts/(square cm-steradian). To obtain spectral radiance units of milliwatts/(square cm-steradian-micron), divide the computed radiance value by the detector bandwidth. The bandwidths for Landsat 4 and 5 in microns, are included in Table 2. Field 35 (bytes 439-441) contains the tape spanning flag, which indicates whether the tape is part of a multi-volume set. This field will be "1/1" (one of one) for tapes containing one or more complete image files and will be either "1/2" or "2/2" for full- scene image files spanning two volumes. Field 37 (bytes 456-460) identifies the first image line on the tape volume. This is "1" unless the tape is the second or higher numbered volume of a multi-volume set (e.g. field 35 is "2/2"). In this case it is the line number in the complete image of the first image line on the tape (nominally N/2 + 1 for two-tape sets, where N is the total number of lines in the image). This is a right-justified ASCII numeric field. Field 39 (bytes 476-480) contains the number of image lines on the tape volume. This is the number of lines in each image file (the same as field 61) for tapes containing one or more complete image files. For multi-volume sets it is the number of image lines on the tape volume (nominally N/2 for two-tape sets, where N is the total number of lines in the image). This is a right- justified ASCII numeric field. Field 41 (bytes 495-500) identifies the orientation angle of the scene. For non-polar scenes the orientation angle of the scene is relative to the scene alignment to map or grid north. For non-polar, map-oriented scenes this field should be zero. A negative angle implies a clockwise rotation of the scene to align with map north whereas a positive angle implies a counterclockwise rotation of the scene to align with map north. To calculate the orientation angle of any image use the following equation: ANGLE = arctan ( NORTHDIFF / EASTDIFF ) Where NORTHDIFF = URNORTH - ULNORTH EASTDIFF = UREAST - ULEAST URNORTH = Upper right corner point Northing (field 77) ULNORTH = Upper left corner point Northing (field 69) UREAST = Upper right corner point Easting (field 75) ULEAST = Upper left corner point Easting (field 67) Field 47 (bytes 560-565) contains the Universal Transverse Mercator zone code or the National Ocean Survey (NOS) State Plane Coordinate System zone code number when either of these map projections are selected (see fields 43 or 45). Field 61 (bytes 1108-1112) would also normally be read before importing the image data files. This field contains the total number of lines in the image and is needed to determine the amount of disk space required for the image. Fields 63-93 (bytes 1117-1344) contain the corresponding corner pixel locations (latitude, longitude, easting, northing) relative to the resampled pixel center for all bands on the current tape volume. To calculate the Northing and Easting of any pixel within the image use the map coordinates of the image corner points and the following equations: PE=((NP-P)(NL-L)ULE+(P-1)(NL-L)URE+(NP-P)(L-1)LLE+(P-1)(L-1)LRE)/((NP-1)(NL-1)) PN=((NP-P)(NL-L)ULN+(P-1)(NL-L)URN+(NP-P)(L-1)LLN+(P-1)(L-1)LRN)/((NP-1)(NL-1)) Where PE = Desired pixel location Easting PN = Desired pixel location Northing ULE = Upper left corner point Easting (field 67) URE = Upper right corner point Easting (field 75) LLE = Lower left corner point Easting (field 91) LRE = Lower right corner point Easting (field 83) ULN = Upper left corner point Northing (field 69) URN = Upper right corner point Northing (field 77) LLN = Lower left corner point Northing (field 93) LRN = Lower right corner point Northing (field 85) P = Pixel number of desired location (counted from left) L = Line number of desired location (counted from top) NP = Number of pixels per image line (field 59) NL = Total number of lines in the output image (field 61) Field 95 (bytes 1361-1367) contains the band identifiers for the image files on the tape volume. This field is composed of seven one-byte sub-fields containing from one to seven of the band identifiers "1", "2", "3", "4", "5", "6", "7". The band identifiers are listed in the order in which the image files appear on the tape and are left justified in the seven-byte ASCII alphanumeric field. Field 97 (bytes 1386-1389) contains the blocking factor used to minimize the number of CCT tapes required to accommodate the image set. This field is always '1' for 8mm tapes or CD-ROMs. Field 99 (bytes 1406-1410) contains the physical tape record length. The value is right justified in an ASCII numeric field. The number of pixels (samples) per image line can be determined by dividing this field by the value in field 97 or by reading field 59 (bytes 1086-1090). Field 101 (bytes 1427-1428) contains the sun elevation angle in degrees for the scene center location at the scene center acquisition time. This angle specifies the solar parallel of altitude on the celestial sphere as referenced from the celestial horizon of the scene center. Field 103 (bytes 1443-1445) contains the sun azimuth (west) in degrees for the scene center location at the scene center acquisition time. This angle specifies the vertical circle (west) on which the sun's location is measured from the principal vertical circle of the scene center. Field 115 (bytes 1528-1531) contains the horizontal offset of the true scene center from the nominal WRS scene center in units of whole pixels. A negative value implies a westerly offset of the scene center from the nominal WRS scene center in daytime scenes (rows 1-120) and an easterly offset of the scene center in nighttime scenes (rows 125-244). SOFTWARE The cartographic software package used in processing the Landsat imagery is described in the following references: General Cartographic Transformation Package (GCTP) Software Reference NOAA Technical Report NOS 124 CGS 9 General Cartographic Transformation Package GCTP, Version II Atef A. Elassal - February 1987 U.S. Dept. of Commerce National Geodetic Information Center, NOAA Rockville, MD 20852 USGS Map Projection Reference Map Projections - A Working Manual U.S. Geological Suvey Professional Paper 1395 (Supersedes USGS Bulletin 1532) John P. Snyder - 1987 U.S.G.S. Map Sales P.O. Box 25286 Denver, CO 80225 APPENDIX A: Path-Oriented Products This appendix contains the map projections and ellipsoid used in EOSAT's path-oriented TM digital products. This list of map projections shows the two-digit USGS projection number found in field 45 of the header file, the name, and the identifier used in field 43 of the header file. The ellipsoid includes the semi-major axis and the semi-minor axis. MAP PROJECTIONS 09 Transverse Mercator TM 21 Space Oblique Mercator SOM 06 Polar Stereographic PS EARTH ELLIPSOID Semi-Major Axis Semi-Minor Axis (Meters) (Meters) International 1909 6378388.000000 6356911.946130 APPENDIX B: Map-Oriented Products This appendix contains the map projections and the ellipsoids used in EOSAT's map-oriented TM digital products. This list of map projections shows the two-digit USGS projection number found in field 43 of the header file, the name, and the identifier used in field 43 of the header file. The list of ellipsoids includes the semi-major axis and the semi-minor axis. MAP PROJECTIONS 01 Universal Transverse Mercator UTM 02 State Plane Coordinate System SPCS 03 Albers Conical Equal Area ACEA 04 Lambert's Conformal Conic LCC 05 Mercator MER 06 Polar Stereographic PS 07 Polyconic PC 08 Equidistant Conic (Type A & B) EC 09 Transverse Mercator (Gauss-Krueger) TM 10 Stereographic SG 11 Lamberts Azimuthal Equal Area LAEA 12 Azimuthal Equidistant AE 13 Gnomonic GNO 14 Orthographic OG 15 General Vertical Near-Side Perspective GVNP 16 Sinusoidal SIN 17 Equirectangular (Plate Carree) ER 18 Miller Cylindrical MC 19 Van Der Grinten I VDG 20 Oblique Mercator (Type A & B) OM 21 Space Oblique Mercator SOM EARTH ELLIPSOIDS Semi-Major Axis Semi-Minor Axis (meters) (meters) Clarke 1866 6378206.400000 6356583.800000 Clarke 1880 6378249.145000 6356514.869550 International 1967 6378157.500000 6356772.200000 International 1909 6378388.000000 6356911.946130 WGS 66 6378145.000000 6356759.769356 WGS 72 6378135.000000 6356750.519915 GRS 1980 6378137.000000 6356752.314140 Airy 6377563.396000 6356256.910000 Modified Airy 6377340.189000 6356034.448000 Everest 6377276.345200 6356075.413300 Modified Everest 6377304.063000 6356103.039000 Mercury 1960 6378166.000000 6356784.283666 Modified Mercury 1968 6378150.000000 6356768.337303 Bessel 6377397.155000 6356078.962840 Walbeck 6376896.000000 6355834.846700 Southeast Asia 6378155.000000 6356773.320500 Australian National 6378160.000000 6356774.719000 Krassovsky 6378245.000000 6356863.018800 Hough 6378270.000000 6356794.343479 6370997 Sphere 6370997.000000 6370997.000000 Field Bytes Format Description 1 1-9 A9 "PRODUCT =" 2 10-20 A11 Product order number in 'yydddnnn-cc' format 3 21-26 A6 " WRS =" 4 27-35 A9 WRS Path/Row/Fraction in 'ppp/rrrff' format 5 36-54 A19 " ACQUISITION DATE =" 6 55-62 A8 Date in 'yyyymmdd' format 7 63-74 A12 " SATELLITE =" 8 75-76 A2 Satellite number: 'L4' 'L5' 9 77-89 A13 " INSTRUMENT =" 10 90-93 A4 Instrument type: 'TMmn' where "m" = mode number "n" = multiplexer number 11 94-108 A15 " PRODUCT TYPE =" 12 109-122 A14 Product type: 'MAP ORIENTED ', 'ORBIT ORIENTED' 13 123-137 A15 " PRODUCT SIZE =" 14 138-147 A10 Product size: 'FULL SCENE', 'SUBSCENE ', 'MAP SHEET ' 15 148-225 A78 Map sheet name (if applicable) 16 226-255 A30 " TYPE OF GEODETIC PROCESSING =" 17 256-265 A10 Type of geodetic processing used: 'SYSTEMATIC', 'PRECISION ', 'TERRAIN ' 18 266-278 A13 " RESAMPLING =" 19 279-280 A2 Resampling algorithm used: 'CC', 'BL', 'NN' 20 281-300 A20 " RAD GAINS/BIASES = " 21 301-316 A16 Maximum and Minimum detectable radiance values for the first band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn' format. The maximum and minimum radiance units: milliwatts/(square cm - steradian). See Detailed Format Description for band gain and bias value conversions. 22 317-317 1X Blank 23 318-333 A16 Maximum and Minimum detectable radiance values for the second band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn' format (if applicable). 24 334-334 1X Blank 25 335-350 A16 Maximum and Minimum detectable radiance values for the third band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn' format (if applicable). 26 351-351 1X Blank 27 352-367 A16 Maximum and Minimum detectable radiance values for the fourth band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn ' format (if applicable). 28 368-368 1X Blank 29 369-384 A16 Maximum and Minimum detectable radiance values for the fifth band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn' format (if applicable). 30 385-385 1X Blank 31 386-401 A16 Maximum and Minimum detectable radiance values for the sixth band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn' format (if applicable). 32 402-402 1X Blank 33 403-418 A16 Maximum and Minimum detectable radiance values for the seventh band (see Field 95) on the tape in 'mm.mmmmm/n.nnnnn ' format (if applicable). 34 419-438 A20 " VOLUME #/# IN SET =" 35 439-441 A3 Tape volume number and number of volumes in tape set in 'n/m ' format (for multi-volume image). 36 442-455 A14 " START LINE #=" 37 456-460 I5 First image line number on this volume (for multi-volume image) 38 461-475 A15 Number of image lines on this volume (for multi-volume image) 40 481-494 A14 " ORIENTATION =" 41 495-500 F6.2 Orientation angle in degrees (may be negative) 42 501-513 A13 " PROJECTION =" 43 514-517 A4 Map projection name 44 518-537 A20 " USGS PROJECTION # =" 45 538-543 I6 USGS projection number 46 544-559 A16 " USGS MAP ZONE =" 47 560-565 I6 USGS map zone 48 566-594 A29 " USGS PROJECTION PARAMETERS =" 49 595-954 15D24.15 The USGS projection parameters in standard USGS order. The meaning of these values depends on the projection used. 50 955-972 A18 " EARTH ELLIPSOID =" 51 973-992 A20 Ellipsoid used 52 993-1010 A18 " SEMI-MAJOR AXIS =" 53 1011-1021 F11.3 Semi-major axis of earth ellipsoid in meters 54 1022-1039 A18 " SEMI-MINOR AXIS =" 55 1040-1050 F11.3 Semi-minor axis of earth ellipsoid in meters 56 1051-1063 A13 " PIXEL SIZE =" 57 1064-1068 F5.2 Pixel size in meters 58 1069-1085 A17 " PIXELS PER LINE=" 59 1086-1090 I5 Number of pixels per image line 60 1091-1107 A17 " LINES PER IMAGE=" 61 1108-1112 I5 Total number of lines in the output image (on all volumes) 62 1113-1116 A4 " UL " 63 1117-1129 A13 Geodetic Longitude of Upper Left corner of image. As per FIPS PUB 70, longitude will be expressed as degrees, minutes, seconds. Example: 5 degrees, 15 minutes, 13.2 seconds west of the prime meridian will be expressed as "0051513.2000W." 64 1130-1130 1X Blank 65 1131-1142 A12 Geodetic Latitude of Upper Left corner of image. As per FIPS PUB 70, latitude will be expressed as degrees, minutes, seconds. Example: 9 degrees, 4 minutes, 24.2334 seconds north of the equator will be expressed as "090424.2334N." 66 1143-1143 1X Blank 67 1144-1156 F13.3 Easting of Upper Left corner of image in meters X 68 1157-1157 1X Blank 69 1158-1170 F13.3 Northing of Upper Left corner of image in meters Y 70 1171-1174 A4 " UR " 71 1175-1187 A13 Geodetic Longitude of Upper Right corner of image 72 1188-1188 1X Blank 73 1189-1200 A12 Geodetic Latitude of Upper Right corner of image 74 1201-1201 1X Blank 75 1202-1214 F13.3 Easting of Upper Right corner of image in meters X 76 1215-1215 1X Blank 77 1216-1228 F13.3 Northing of Upper Right corner of image in meters Y 78 1229-1232 A4 " LR " 79 1233-1245 A13 Geodetic Longitude of Lower Right corner of image 80 1246-1246 1X Blank 81 1247-1258 A12 Geodetic Latitude of Lower Right corner of image 82 1259-1259 1X Blank 83 1260-1272 F13.3 Easting of Lower Right corner of image in meters X 84 1273-1273 1X Blank 85 1274-1286 F13.3 Northing of Lower Right corner of image in meters Y 86 1287-1290 A4 " LL " 87 1291-1303 A13 Geodetic Longitude of Lower Left corner of image 88 1304-1304 1X Blank 89 1305-1316 A12 Geodetic Latitude of Lower Left corner of image 90 1317-1317 1X Blank 91 1318-1330 F13.3 Easting of Lower Left corner of image in meters X 92 1331-1331 1X Blank 93 1332-1344 F13.3 Northing of Lower Left corner of image in meters Y 94 1345-1360 A16 " BANDS PRESENT =" 95 1361-1367 A7 Bands present on this volume 96 1368-1385 A18 " BLOCKING FACTOR =" 97 1386-1389 I4 Tape blocking factor 98 1390-1405 A16 " RECORD LENGTH =" 99 1406-1410 I5 Length of physical tape record 100 1411-1426 A16 " SUN ELEVATION =" 101 1427-1428 I2 Sun elevation angle in degrees at scene center 102 1429-1442 A14 " SUN AZIMUTH =" 103 1443-1445 I3 Sun azimuth in degrees at scene center 104 1446-1453 A8 " CENTER " 105 1454-1466 A13 Scene center geodetic longitude expressed in degrees, minutes, seconds as above. This is the true center of the full scene from which the product image was made, and does not necessarily fall inside the product image. 106 1467-1467 1X Blank 107 1468-1479 A12 Scene center geodetic latitude expressed in degrees, minutes, seconds as above. This is the true center of the full scene from which the product image was made, and does not necessarily fall inside the product image. 108 1480-1480 1X Blank 109 1481-1493 F13.3 Scene center easting in meters X 110 1494-1494 1X Blank 111 1495-1507 F13.3 Scene center northing in meters Y 112 1508-1513 I6 Scene center pixel number measured from the product upper left corner, rounded to nearest whole pixel (may be negative). 113 1514-1519 I6 Scene center line number measured from the product upper left corner, rounded to nearest whole line (may be negative). 114 1520-1527 A8 " OFFSET=" 115 1528-1531 I4 Horizontal offset of the true scene center from the nominal WRS scene center in units of whole pixels (as specified in the pixel size field (Field 57)). May be negative. 116 1532-1535 A4 " REV" 117 1536-1536 A1 Format version code (A-Z). This document describes version B.