User's Guide

COMPATM

Generate water vapor, ozone, and quality control bands

Function:

If atmospheric correction is to be applied to an image using ATMOCOR, associated images the same size and in the same space must be available. COMPATM generates water vapor, ozone, and quality control images that are the same size and in the same space as the input image.

Parameters:

OZONE
An ozone image for each month used in the composite. The first ozone image specified here is expected to coincide with the first date in DATELIST. For example, if datelist[0] = "082499", then an ozone image for the month of august should be specified first (ozone[0] = "stdozone8" ). Since a composite doesn't span more than 20 days at most, there is never more than two applicable months. The ozone images are expected to be 180 lines by 360 samples, and in geographic space.

NOZONE
Number of ozone images. The number of images specified in OZONE.

WATERDIR
Water vapor image directory. Directory in which the images specified in WATER reside.

WATER
Water vapor image(s). A water vapor image must be specified for each day used in the composite. The water vapor images are expected to be 180 lines by 360 samples, and in geographic space.

QCDIR
Quality control image directory. Directory in which the images specified in QC reside.

QC
Quality control image(s). A quality control image must be specified for each day used in the composite. These images are expected to be 180 lines by 360 samples, and in geographic space. The following quality control values signify a water vapor value:


0:  taken from a daily acquisition
1:  taken from a daily climatology
2:  taken from a monthly climatology
3:  created using a nearest-neighbor fill

NWATER
Number of water vapor images specified in WATER (and also the number of quality control images specified in QC).

DATEBAND
Composite date band. The 'date band' generated during the creation of the composite. The band signifies which acquisition image each pixel in the composite came from. This image is expected to be the same size and in the same space as the composite.

SOLZEN
Solar zenith band. The solar zenith angles for the composite image. This image is expected to be the same size and in the same space as the composite. SOLZEN is used to update the QCOUT image.

LINES
Lines image. The values in this image are used as line indices into WATER (water vapor images) and QC (quality control images). This image is expected to be the same size and in the same space as the composite.

SAMPLES
Samples image. The values in this image are used as sample indices into WATER (water vapor images) and QC (quality control images). This image is expected to be the same size and in the same space as the composite.

SCENELIST
List of scenes. A list of scenes as returned by REATMOINFO. A list containing the scenes used in the composite. All entries in the list with a value of "-1" signify that the scene was not used in the composite. For example, if SCENELIST(5) = -1, then we know that scene number 5 was not used in the composite. Otherwise, the positive entry is used as an index into the DATELIST array. For example, if SCENELIST(4) = 3, then scene number 4 was used in the composite, and the date of scene number 4 is stored in DATELIST(3).

DATELIST
Date listing as returned by REATMOINFO. The list of dates used in the composite. Entries are of the form "MMDDYY".

SCALE
Scaling technique used to generate the composite.


US     US scaling technique
GLOBAL Global 1km scaling technique

OUT
Output image. Image containing the appropriate water vapor value for each pixel, taken from the appropriate input water vapor image (band 1). Band 2 contains the appropriate ozone value for each pixel, taken from the appropriate input ozone image. This image will be the same size and in the same space as the composite.

QCOUT
Output quality control image. Image will contain the following quality control values:


0:    Water vapor value taken from a daily
      acquisition, normal solar zenith angle
1:    Water vapor value taken from a daily
      climatology, normal solar zenith angle
2:    Water vapor value taken from a monthly
      climatology, normal solar zenith angle
3:    Water vapor value created using nearest-
      neighbor fill, normal solar zenith angle

100:  Water vapor value taken from a daily
      acquisition, extreme solar zenith angle
101:  Water vapor value taken from a daily
      climatology, extreme solar zenith angle
102:  Water vapor value taken from a monthly
      climatology, extreme solar zenith angle
103:  Water vapor value created using nearest-
      neighbor fill, extreme solar zenith angle
255:  Undefined pixel value

Examples:

  1. LAS> compatm ozone=("stdozone8","stdozone9") nozone=2 waterdir="[mydir.somedir.waterdir]" water=("wtrimg1","wtrimg2","wtrimg3") qcdir="[mydir.somedir.qcdir]" qc=("qcimg1","qcimg2","qcimg3") nwater=3 dateband="us_232245(:10)" solzen="us_232245(:8)" lines="getatmout(:2)" samples="getatmout(:3)" scenelist=@scenelist datelist=@datelist scale="us" out="compatmout" qcout="compqcout"

    The user has requested to process a composite consisting of images from 3 days, with those days spanning a month. OUT will contain 2 bands, a water vapor band and an ozone band. QCOUT will contain a quality control band.

Description/Algorithm:

The TAE input parameters are retrieved. The images in geographic space are read into buffers. This includes a water vapor band for each day used in the composite, a quality control band for each day used in the composite, and an ozone band for each month used in the composite. The input images in composite space (date band, solar zenith band, 'lines' band, and 'samples' band) are processed one pixel at a time. The date band pixel is used to determine from which acquisition image the composite pixel came from (and consequently the acquisition date of the pixel). The solar zenith band is used to construct the quality control output band. The 'lines' band and 'samples' bands are used as indices into the geographic images. The water vapor values are selected from the appropriate water vapor images (per pixel). The ozone band is created from the appropriate ozone monthly images (per pixel). The quality control image is also generated in the same space as the input composite image.

Nonfatal Error Message:

  1. [compatm-warn] Nonfatal error encountered

    A nonfatal error was encountered during processing. The error message that is displayed immediately preceding this message is the specific error that was encountered. Processing will continue.

Fatal Error Messages:

  1. [compatm-fatal] Fatal error encountered

    A fatal error was encountered during processing. Processing is terminated. The error message that is displayed immediately preceding this message is the specific error that was encountered.

  2. [compatm-badbnd] Invalid number of input bands specified

    An input image was not specified with the correct number of bands. Examine the input image specification and rerun.

  3. [compatm-badimg] Invalid number of input images specified

    The number of input images was not specified correctly. Examine the input image specification and rerun.

  4. [compatm-gtbuf] Error reading image <XXXXXX>

    An error occurred reading the image data. Ensure the image exists with the proper permissions.

  5. [compatm-clos] Error closing file <XXXXXX>

    An error occurred closing the file. Contact the system administrator if the error persists.

  6. [compatm-alloc] Error allocating dynamic memory

    An error occurred while trying to allocate memory. Contact the system administrator if the error persists.

  7. [compatm-numv] Invalid number of <XXXXXX> images specified

    The number of images specified in OZONE and WATER must be consistent with the value specified in NWATER. Specify a consistent value for each of the above parameters and rerun.

  8. [compatm-band] Invalid date band specification

    A date band mismatch has occurred. Ensure that the date band image and date band log file coincide and rerun.

User Notes:

  1. This module was written to reprocess existing composites to apply atmospheric correction with water vapor being considered.