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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