Landsat Pathfinder Program
North American Landscape Characterization Product README
U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) DATA PRODUCT: NORTH AMERICAN LANDSCAPE CHARACTERIZATION (NALC) PRODUCT README TABLE OF CONTENTS INTRODUCTION FORMAT ORGANIZATION * DATA FILE NAMES * README * READING DATA RETURN PRODUCT POLICY DISCLAIMER CONTACT SUPPORT REFERENCES APPENDICES * SAMPLE IMAGE METADATA * METADATA FIELD DESCRIPTIONS * SAMPLE DATA DESCRIPTOR INTRODUCTION The NALC project includes Landsat MSS data acquired in the years 1973, 1986, and 1991, plus or minus one year, with geographic coverage consisting of the conterminous United States and Mexico. The specific temporal windows vary for geographic regions based on the seasonal characteristics of the vegetation cover. The NALC triplicate scenes are geographically referenced to a 60- by 60-meter UTM ground coordinate grid and the North American Datum 27 (NAD27). FORMAT NALC products are in Generic Binary format, with the bands written Band Sequential (BSQ). Ancillary files are American Standard Code for Information Interchange (ASCII) format, including a data descriptor file and a metadata file. NALC images are BYTE data (also known as 8-bit unsigned integer data). ORGANIZATION * DATA FILE NAMES The following file structure is for explanatory purposes only. The actual number of files may vary slightly, depending upon the requirements for cloud compositing and the creation date of the triplicate. Since NALC triplicates vary in total size, they are distributed accordingly on either one or two compact discs. IMG70_1.DAT: File contains image data in BSQ format. IMG70_1.DDA: File contains ASCII dump of data descriptor record. IMG70_1.TXT: File contains image metadata. IMG80_1.DAT: File contains image data in BSQ format. IMG80_1.DDA: File contains ASCII dump of data descriptor record. IMG80_1.TXT: File contains image metadata. IMG90_1.DAT: File contains image data in BSQ format. IMG90_1.DDA: File contains ASCII dump of data descriptor record. IMG90_1.TXT: File contains image metadata. Files are in order by date (1970.s file(s), 1980.s file(s), 1990.s file(s), and the readme file). The DDA file contains an ASCII dump of a data descriptor record file containing geographic coordinates that are always based on the 1980's scene (also referred to as the reference scene). The Universal Transverse Mercator (UTM) corner points correspond to the center of the pixel of the four corners of the array. The array contains the full geocoded scene, including the zero-fill and annotation area. As of June 14, 1993, all 1970's images contain five bands (i.e., multispectral scanner (MSS) bands 1 through 4 and a pixel identity image) and all 1980's and 1990's images contain six bands (i.e., MSS bands 1 through 4, normalized difference vegetation index (NDVI), and a pixel identity image). Beginning on July 28, 1994, full terrain correction was implemented on all triplicate components. * README The readme.txt is a text file and is this document. * READING DATA NALC data are provided in a generic image array format (flat, headerless, binary raster data) to maximize the flexibility for importing into a variety of software systems. The USGS does not provide the software necessary to view or analyze these data. Many geographic information system and image processing packages commonly include modules to import generic raster data. To import the data, the user needs to identify the size of the raster array (the number of lines or rows and number of samples or columns). This information is found in the data descriptor file. Data delivery available for NALC products: CD, DVD or File download; Data files use the 8.3 file naming convention in accordance with the ISO-9660 Level-1 standard. RETURN PRODUCT POLICY Customers are entitled to exchanges or refunds (if applicable) for faulty products for a period of 60 days from the date of shipment. Returned products must be accompanied by a copy of the shipping summary and a letter describing in detail the reason for the return. Questions regarding this procedure can be directed to USGS/EROS Customer Services at 605-594-6151, 800-252-4547 or email: custserv@usgs.gov. DISCLAIMER No warranty is expressed or implied regarding the utility of this product. CONTACT SUPPORT For information or questions concerning NALC products or orders, contact: USGS/EROS Attn: Customer Service Sioux Falls, SD 57198-0001 Telephone: +1 605-594-6151 Toll Free: +1 800-252-4547 Facsimile: +1 605-594-6589 E-mail: custserv@usgs.gov Information about other USGS products can be found online at: http://eros.usgs.gov or http://www.usgs.gov or by calling 1-888-ASK-USGS (275-8747) REFERENCES USGS NALC Product page: http://eros.usgs.gov/products/satellite/nalc.html NALC User Guide: http://edcsns17.cr.usgs.gov/helpdocs/V0guide/campaign_documents/nalc_proj_camp.html APPENDICES * SAMPLE IMAGE METADATA path_nbr = 46 row_nbr = 26 proc_level = T ctr_latitude = 48.86666 ctr_longitude = -121.31666 scene_decade = 80 date_entered = 11/01/94 map_projection_code = U data_format = EDIP resampling_tech = C scene_id_1 = 5046026008523590 cloud_cover_1 = 0 control_pts_1 = 44 rms_err_1 = 0.86 acq_date_1 = 08/28/85 sun_elev_1 = 45 sun_azimuth_1 = 133 comments_1 = None * METADATA FIELD DESCRIPTIONS Iterations of .TXT files may apply. _n = scene number [_1, _2, _3] PATH_NBR = A nominal Landsat satellite track (path) as defined by the WRS. All NALC data are referenced to WRS-2 (Landsats 4 and 5). Valid values are: 010-048 ROW_NBR = A nominal center latitude line of a Landsat image as defined by the WRS. The row indicator represents scene centers that are chosen at 23.92-second (Landsats 4 and 5) increments along the orbital track in either direction of the Equator. Valid values are: 026-050 = Northern Hemisphere (Descending) PROC_LEVEL = Level of processing performed on the scene. Valid values are: C = Composite G = Geocoded/georegistered T = Terrain corrected/georegistered CTR_LATITUDE = Center latitude of triplicate WRS-2 path/row. The plus (+) sign indicates the coordinate is in the Northern Hemisphere. All coordinates are stored as decimal degrees. CTR_LONGITUDE = Center longitude of triplicate WRS-2 path/row. The minus (-) sign indicates the coordinate is in the Western Hemisphere. All coordinates are stored as decimal degrees. SCENE_DECADE = The decade of the scene (70, 80, 90). DATE_ENTERED = The date the metadata record was added to the data base. MAP_PROJECTION_CODE = Map projection. Valid value is: U = Universal Transverse Mercator (UTM) DATA_FORMAT = The data's original input format. Valid values are: CCTX = EROS computer compatible tape in X format EDIP = EROS Digital Image Processing System's format FAST = EOSAT's Fast Format RESAMPLING_TECH = Resampling technique used to radiometrically process the data. Valid values are: BI = Bilinear CC = Cubic convolution SCENE_ID_n = Identification for a systematically corrected scene. If more than one scene ID is listed, then each listed scene was used in the generation of a composite. CLOUD_COVER_n = Percentage of image obscured by clouds and cloud shadows for the scene. Represented in increments of 10 percent. CONTROL_PTS_n = Number of geographic control points used for the scene. RMS_ERR_n = The average root-mean-square error derived using the scene's control points. ACQ_DATE_n = The acquisition date applicable to the scene. Current Landsat operating window: 1972-Present SUN_ELEV_n = The elevation angle of the Sun above the horizon in degrees. Valid values are: 0-90 SUN_AZIMUTH_n = The azimuth angle of the Sun measured clockwise from north in degrees. Valid values are: 0-360 COMMENTS_n = Field for comments or problem statements applicable to the scene. * SAMPLE DATA DESCRIPTOR Information in the data descriptor file that is of direct interest to users (PARAMETER:VALUE) includes: NL:Number of Lines NS:Number of Samples NB:Number of Bands PROJ.CODE:Map Projection Code (always UTM) ZONE CODE:UTM Zone ULcorner:UTM northing, easting of upper left corner URcorner:UTM northing, easting of upper right corner LLcorner:UTM northing, easting of lower left corner LRcorner:UTM northing, easting of lower right corner PROJ.UNITS:Projection Units (meters) The four corners defined by ULcorner, URcorner, LLcorner, LRcorner are the UTM coordinates for the corners of the data file, including the zero-fill area. The coordinates reference the center of the pixel. IMAGE NAME:img80_1.ddr NL:3883 NS:4097 NB:4 DTYPE:BYTE LAST MODIFIED: DATE:10-Feb-93 TIME:1643:01 SYSTEM:ieee-std PROJ. CODE:(1)UTM Valid:VALID ZONE CODE:15 Valid:VALID DATUM CODE:0 Valid:VALID PROJ. PARM: Valid:INVALID A: 0.000000000000000E+00 0.00000000000000E-00 0.00000000000000E-00 B: 0.00000000000000E+00 0.00000000000000E+00 0.00000000000000E+00 C: 0.00000000000000E+00 0.00000000000000E+00 0.00000000000000E+00 D: 0.00000000000000E+00 0.00000000000000E+00 0.00000000000000E+00 E: 0.00000000000000E+00 0.00000000000000E+00 0.00000000000000E+00 CORNER COOR: Valid:VALID ULcorner:1.70538000000000E+06 4.44960000000000E+05 URcorner:1.70538000000000E+06 7.44900000000000E+05 LLcorner:1.40544000000000E+06 4.44960000000000E+05 LRcorner:1.40544000000000E+06 7.44900000000000E+05 PROJ. DIST:6.00000000000000E+01 6.00000000000000E+01 Valid:VALID PROJ. UNITS:METERS Valid:VALID INCREMENT:1.00000000000000E+00 1.00000000000000E+00 Valid:VALID MASTER COOR:1 1 IMAGE NAME:85068515574x0.trimp BAND NO:1 MINIMUM:0.00000000000000E+00 Valid:INVALID MAXIMUM:0.00000000000000E+00 Valid:INVALID DATA SOURCE:landsat 5 SENSOR TYPE:mss CAPT. DIRECTION:descending DATE:15-JAN-86 TIME:1557:4 IMAGE NAME:85068515574x0.trimp BAND NO:2 MINIMUM:0.00000000000000E+00 Valid:INVALID MAXIMUM:0.00000000000000E+00 Valid:INVALID DATA SOURCE:landsat 5 SENSOR TYPE:mss CAPT. DIRECTION:descending DATE:15-JAN-86 TIME:1557:4 IMAGE NAME:85068515574x0.trimp BAND NO:3 MINIMUM:0.00000000000000E+00 Valid:INVALID MAXIMUM:0.00000000000000E+00 Valid:INVALID DATA SOURCE:landsat 5 SENSOR TYPE:mss CAPT. DIRECTION:descending DATE:15-JAN-86 TIME:1557:4 IMAGE NAME:85068515574x0.trimp BAND NO:4 MINIMUM:0.00000000000000E+00 Valid:INVALID MAXIMUM:0.00000000000000E+00 Valid:INVALID DATA SOURCE:landsat 5 SENSOR TYPE:mss CAPT. DIRECTION:descending DATE:15-JAN-86 TIME:1557:4 IMAGE NAME:85068515574x0.trimp Publication Date: 11/17/2006