User's Guide

AUTONAV

Performs automatic navigation of an AVHRR image

Function:

Performs automatic navigation of an AVHRR image. The navigation consists of updates to the roll, pitch, yaw, and altitude of the satellite model. The updates are calculated by correlating small windows of the AVHRR image ("chips") with either small portions of Digital Chart of the World line work or a registered base image.

Parameters:

Subcommand -BASE:
Navigation using a base image

IN
Input images. The first image is the base image from which chips will be taken. The second image is the AVHRR image to be navigated. No bands should be specified.

INTS
Input tie point selection file. This file specifies tie points, whose latitude and longitude coordinates become the center of each chip.

DELFLG(NO)
Delete flag. Delete the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR.


    = YES: Delete intermediate tie point files
    = NO:  Do not delete intermediate tie point files

PRINT("TERM")
Output destination. The destination of the output.


  = TERM:      Terminal.  Output is sent to the user's 
               terminal.
  = LP:        Line printer.  Output is sent to the 
               printer defined by $PRINTER.
  = Filename:  User-supplied filename.  Output is sent 
               to the user-supplied file with the ex-
               tension ".prt".

SAVEDIR(--)
Save directory. The directory in which to save the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR. The plot files and database files from NAVIGATE are also saved in this directory. If not specified, these files will not be saved (except for tie point files which may be left in the working directory, depending on the value of DELFLG). The files saved in SAVEDIR will have a unique file name prefix (see PREFIX).

PREFIX(-- )
File prefix. The unique file name prefix used by the files saved in SAVEDIR (if SAVEDIR is not specified, PREFIX is not used). The following syntax is recommended:


    s06_12041622_

     06		    Study area
        12	    Month of scene acquisition
	  04	    Day of scene acquisition
	    16	    Starting hour of scene acquisition
	      22    Starting minute of scene acquisition

If SAVEDIR is specified, but PREFIX is not, the following default file name syntax will be generated:


    s06_12041622_

     06		    Study area
        12	    System month
	  04	    System day
	    16	    System hour
	      22    System minute

SAREA(--)
Study area. Specifies the area of interest defined by the 12 regions of the global GOODES projection. If specified, this information is used only for statistical purposes.
Subcommand -DCW:
Navigation using DCW

IN
Input image. The AVHRR image to be navigated. Image chips of DCW line work will be created in the same space as IN. No bands should be specified.

INTS
Input tie point selection file. This file specifies tie points, whose latitude and longitude coordinates become the center of each chip.

THRVAL(325.0)
Threshold value. The threshold pixel value for screening out cloud image data. Any pixel value above THRVAL will not be used in the correlation process. A table of suggested values follows:


  	      | REFLECTANCE |      RADIANCE (AVHRR CHANNEL 2)
  SCALING     |     50%     | n11 = 168 | n12 = 167 | n14 = 164
  ------------|-------------|-----------|-----------|----------
  US Byte     |      200    |    129    |    128    |    126
  US I*2      |      500    |   1680    |   1670    |   1640
  US I*4      |      500    |   1680    |   1670    |   1640
  US Real     |       50    |    168    |    167    |    164
  Global Byte |       60    |     86    |     86    |     84
  Global I*2  |      510    |    325    |    323    |    317
  Global I*4  |     5010    |  16810    |  16710    |  16410
  Global Real |       60    |    178    |    177    |    174

For example, 325.0 is the cloud threshold value to use for I*2 images from NOAA-11 channel 2 which have been calibrated and scaled with global scaling, and whose AVHRR channel 2 is in radiance values. 500.0 is the cloud threshold value to use for I*2 images which have been calibrated and scaled with US scaling, and whose visible bands are reflectance values. See the User Note 2 for more details.

LIBRARY("NOAMER" COUNT=(1:4)
DCW Library. The DCW library that lines will be extracted from. The DCW is divided into four libraries. Each library exists on a single CD, or in a single directory on disk. These libraries are:


    = NOAMER:      North America
    = EURNASIA:    Europe and Northern Asia
    = SOAMAFR:     South America and Africa
    = SASAUS:      South Asia and Australia

DELFLG(NO)
Delete flag. Delete the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR.


    = YES: Delete intermediate tie point files
    = NO:  Do not delete intermediate tie point files

PRINT("TERM")
Output destination. The destination of the output.


  = TERM:      Terminal.  Output is sent to the user's 
               terminal.
  = LP:        Line printer.  Output is sent to the 
               printer defined by $PRINTER.
  = Filename:  User-supplied filename.  Output is sent 
               to the user-supplied file with the ex-
               tension ".prt".

SAVEDIR(--)
Save directory. The directory in which to save the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR. The plot files and database files from NAVIGATE are also saved in this directory. If not specified, these files will not be saved (except for tie point files which may be left in the working directory, depending on the value of DELFLG). The files saved in SAVEDIR will have a unique file name prefix (see PREFIX).

PREFIX(-- )
File prefix. The unique file name prefix used by the files saved in SAVEDIR (if SAVEDIR is not specified, PREFIX is not used). The following syntax is recommended:


    s06_12041622_

     06		    Study area
        12	    Month of scene acquisition
	  04	    Day of scene acquisition
	    16	    Starting hour of scene acquisition
	      22    Starting minute of scene acquisition

If SAVEDIR is specified, but PREFIX is not, the following default file name syntax will be generated:


    s06_12041622_

     06		    Study area
        12	    System month
	  04	    System day
	    16	    System hour
	      22    System minute

SAREA(--)
Study area. Specifies the area of interest defined by the 12 regions of the global GOODES projection. If specified, this information is used only for statistical purposes.
Subcommand -LINEBASE:
Navigation using a vector base image

IN
Input images. The first image is the base image that contains rasterized vector data, from which chips will be taken. The second image is the AVHRR image to be navigated. No bands should be specified.

INTS
Input tie point selection file. This file specifies tie points, whose latitude and longitude coordinates become the center of each chip.

THRVAL(325.0)
Threshold value. The threshold pixel value for screening out cloud image data. Any pixel value above THRVAL will not be used in the correlation process. A table of suggested values follows:


  	      | REFLECTANCE |      RADIANCE (AVHRR CHANNEL 2)
  SCALING     |     50%     | n11 = 168 | n12 = 167 | n14 = 164
  ------------|-------------|-----------|-----------|----------
  US Byte     |      200    |    129    |    128    |    126
  US I*2      |      500    |   1680    |   1670    |   1640
  US I*4      |      500    |   1680    |   1670    |   1640
  US Real     |       50    |    168    |    167    |    164
  Global Byte |       60    |     86    |     86    |     84
  Global I*2  |      510    |    325    |    323    |    317
  Global I*4  |     5010    |  16810    |  16710    |  16410
  Global Real |       60    |    178    |    177    |    174

For example, 325.0 is the cloud threshold value to use for I*2 images from NOAA-11 channel 2 which have been calibrated and scaled with global scaling, and whose AVHRR channel 2 is in radiance values. 500.0 is the cloud threshold value to use for I*2 images which have been calibrated and scaled with US scaling, and whose visible bands are reflectance values. See the User Note 2 for more details.

DELFLG(NO)
Delete flag. Delete the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR.


    = YES: Delete intermediate tie point files
    = NO:  Do not delete intermediate tie point files

PRINT("TERM")
Output destination. The destination of the output.


  = TERM:      Terminal.  Output is sent to the user's 
               terminal.
  = LP:        Line printer.  Output is sent to the 
               printer defined by $PRINTER.
  = Filename:  User-supplied filename.  Output is sent 
               to the user-supplied file with the ex-
               tension ".prt".

SAVEDIR(--)
Save directory. The directory in which to save the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR. The plot files and database files from NAVIGATE are also saved in this directory. If not specified, these files will not be saved (except for tie point files which may be left in the working directory, depending on the value of DELFLG). The files saved in SAVEDIR will have a unique file name prefix (see PREFIX).

PREFIX(-- )
File prefix. The unique file name prefix used by the files saved in SAVEDIR (if SAVEDIR is not specified, PREFIX is not used). The following syntax is recommended:


    s06_12041622_

     06		    Study area
        12	    Month of scene acquisition
	  04	    Day of scene acquisition
	    16	    Starting hour of scene acquisition
	      22    Starting minute of scene acquisition

If SAVEDIR is specified, but PREFIX is not, the following default file name syntax will be generated:


    s06_12041622_

     06		    Study area
        12	    System month
	  04	    System day
	    16	    System hour
	      22    System minute

SAREA(--)
Study area. Specifies the area of interest defined by the 12 regions of the global GOODES projection. If specified, this information is used only for statistical purposes.
Subcommand -MULTI:
Navigate using multiple vector sources

IN
Input image. The AVHRR image to be navigated. Image chips of WVS line work will be created in the same space as IN. No bands should be specified. If NAVIGATE fails using WVS chips with INTS(1), it will add more chips and points using DCW chips and INTS(2). If NAVIGATE still fails, it will add still more chips and points using DCW chips and INTS(3).

INTS
Input tie point selection file. This file specifies tie points, whose latitude and longitude coordinates become the center of each chip.

INTS
Input tie point selection files. These files specify tie points, whose latitude and longitude coordinates become the center of each chip. The first file is used for creating WVS chips, so points should be located along coastlines. The second file is used for DCW chips, and points should be located on major inland water bodies. The third file is also used for DCW chips, and points should be located on minor inland water bodies.

VECTSRC(/SGS4/DCW/WVS)
Vector source. This value defines the root directory of the WVS vector data.

THRVAL(325.0)
Threshold value. The threshold pixel value for screening out cloud image data. Any pixel value above THRVAL will not be used in the correlation process. A table of suggested values follows:


  	      | REFLECTANCE |      RADIANCE (AVHRR CHANNEL 2)
  SCALING     |     50%     | n11 = 168 | n12 = 167 | n14 = 164
  ------------|-------------|-----------|-----------|----------
  US Byte     |      200    |    129    |    128    |    126
  US I*2      |      500    |   1680    |   1670    |   1640
  US I*4      |      500    |   1680    |   1670    |   1640
  US Real     |       50    |    168    |    167    |    164
  Global Byte |       60    |     86    |     86    |     84
  Global I*2  |      510    |    325    |    323    |    317
  Global I*4  |     5010    |  16810    |  16710    |  16410
  Global Real |       60    |    178    |    177    |    174

For example, 325.0 is the cloud threshold value to use for I*2 images from NOAA-11 channel 2 which have been calibrated and scaled with global scaling, and whose AVHRR channel 2 is in radiance values. 500.0 is the cloud threshold value to use for I*2 images which have been calibrated and scaled with US scaling, and whose visible bands are reflectance values. See the User Note 2 for more details.

COMBFLG(YES)
Combine flag. Flag indicating whether or not to combine points from the first tie points file (used to create WVS chips) with points from the second tie point file (used to create DCW chips) before attempting to navigate.

  = YES: Combine points from the first and second tie point
         files before attempting to navigate.  If the navigation
         fails, AUTONAV will go on to add more points using DCW
         chips and INTS(3) and will retry navigation.
  = NO:  Do not combine points from the first and second tie 
	 point files.  NAVIGATE will be attempted individually 
         for each input tie point file.

LIBRARY("NOAMER" COUNT=(1:4)
DCW Library. The DCW library that lines will be extracted from. The DCW is divided into four libraries. Each library exists on a single CD, or in a single directory on disk. These libraries are:


    = NOAMER:      North America
    = EURNASIA:    Europe and Northern Asia
    = SOAMAFR:     South America and Africa
    = SASAUS:      South Asia and Australia

DELFLG(NO)
Delete flag. Delete the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR.


    = YES: Delete intermediate tie point files
    = NO:  Do not delete intermediate tie point files

PRINT("TERM")
Output destination. The destination of the output.


  = TERM:      Terminal.  Output is sent to the user's 
               terminal.
  = LP:        Line printer.  Output is sent to the 
               printer defined by $PRINTER.
  = Filename:  User-supplied filename.  Output is sent 
               to the user-supplied file with the ex-
               tension ".prt".

SAVEDIR(--)
Save directory. The directory in which to save the intermediate merged tie point and tie point location files created by AVHRRCHIPS, DCWCHIPS, CORRELATE, and EDITCORR. The plot files and database files from NAVIGATE are also saved in this directory. If not specified, these files will not be saved (except for tie point files which may be left in the working directory, depending on the value of DELFLG). The files saved in SAVEDIR will have a unique file name prefix (see PREFIX).

PREFIX(-- )
File prefix. The unique file name prefix used by the files saved in SAVEDIR (if SAVEDIR is not specified, PREFIX is not used). The following syntax is recommended:


    s06_12041622_

     06		    Study area
        12	    Month of scene acquisition
	  04	    Day of scene acquisition
	    16	    Starting hour of scene acquisition
	      22    Starting minute of scene acquisition

If SAVEDIR is specified, but PREFIX is not, the following default file name syntax will be generated:


    s06_12041622_

     06		    Study area
        12	    System month
	  04	    System day
	    16	    System hour
	      22    System minute

SAREA(--)
Study area. Specifies the area of interest defined by the 12 regions of the global GOODES projection. If specified, this information is used only for statistical purposes.

Examples:

  1. LAS> autonav-base in=("/sg1/csb/lasdev/images/us" "/sg1/csb/lasdev/images/ah11050693211322") ints=/sg1/csb/lasdev/test/tps/namerica print=--

    The tie point selection file namerica.tps will be used to create chips. A window from the base image US is be extracted and warped into the satellite perspective for each point. The chips are then correlated with ah11050693211322.img. The resulting sets of tie point location pairs are edited with a maximum residual of 1.25. The edited points are then used to calculate model updates which are stored in ah11050693211322.addr. No reports are printed.

  2. LAS> autonav-dcw in="/sg1/csb/lasdev/images/ah11050693211322" ints=/sg1/csb/lasdev/test/tps/namerica thrval=510.0 print=dcwrep savedir="/sg1/csb/lasdev/savedir/" prefix="s03_11031634_" sarea=3

    The tie point selection file namerica.tps will be used to create DCW chips for each point that is located within ah11050693211322. Each chip is warped into the satellite perspective of IN. The chips are then correlated with ah11050693211322.img, thresholding out pixel values greater than 510. The edited points are then used to calculate model updates which are stored in ah11050693211322.addr. A report on the fit of the points used in NAVIGATE is written to dcwrep.prt. The merge tie point files, tie point location files, navigation plot files, and navigation database files are saved in "/sg1/csb/lasdev/savedir/" with a prefix name of "s03_11031634_". The study area "3" is stored in the data base generated by NAVIGATE.

Description/Algorithm:

-BASE subcommand:

Automatic navigation with a base image begins by calling AVHRRCHIPS to create chips from the base image IN(1) in the satellite perspective of the AVHRR image IN(2). The resulting merged tie point file is used to correlate the chips to the corresponding window in the AVHRR image, yielding a tie point location file. The sets of tie points are edited using EDITCORR-MODEL with a 1.0 maximum residual. The edited sets of points are then used in NAVIGATE to calculate model updates which are written into the AVHRR image's ADDR file (.addr).

-DCW subcommand

Automatic navigation with the DCW begins by calling DCWCHIPS to create chips of DCW line work in the satellite perspective of the AVHRR image IN. The resulting merged tie point file is used to correlate the chips to the corresponding window in the AVHRR image, yielding a tie point location file. The sets of tie points are edited using EDITCORR-MODEL. The edited sets of points are then used in NAVIGATE to calculate model updates which are written into the AVHRR image's ADDR file (.addr).

-LINEBASE subcommand:

The -LINEBASE subcommand is a combination of the -BASE and -DCW subcommands. AVHRRCHIPS is used to create chips from the base image IN(1) that contains rasterized vector data, such as DCW. The chips are warped into the satellite perspective of the AVHRR image IN(2). The resulting merged tie point file is used to correlate the chips to the corresponding window in the AVHRR image, yielding a tie point location file. The sets of tie points are edited using EDITCORR-MODEL. The edited sets of points are then used in NAVIGATE to calculate model updates which are written into the AVHRR image's ADDR file (.addr).

-MULTI subcommand:

Automatic navigation with multiple vector sources begins by calling WVSCHIPS to create chips of WVS line work in the satellite perspective of the AVHRR image IN centered at points specified in INTS(1). The resulting merged tie point file is used to correlate the chips to the corresponding window in the AVHRR image, yielding a tie point location file. The sets of tie points are edited using EDITCORR-MODEL. The edited sets of points are then used by NAVIGATE. If NAVIGATE completes successfully, model updates are written into the AVHRR image's ADDR file (.addr). If NAVIGATE fails, the tie point location file (TPL) is retained but the WVS chips are removed. DCW chips are then created using INTS(2) and correlated, producing a second TPL file. The two TPL files are combined and input to NAVIGATE. If NAVIGATE fails again, the chips are removed, and new DCW chips are created using INTS(3). These chips are correlated, and the resulting TPL file is combined with the previous two and input to NAVIGATE. If NAVIGATE still fails, the chips are removed and AUTONAV terminates. If NAVIGATE is successful on any of the above three attempts, the calculated model updates are written into the AVHRR image's ADDR file (.addr) and AUTONAV terminates.

Nonfatal Error Messages:

    None.

Fatal Error Messages:

  1. [autonav-fatal] Fatal error encountered

    The message displayed immediately preceding this message is the specific error encountered. Processing is terminated.

  2. [autonav-abort] User aborted processing

    The user aborted the execution of this procedure.

User Notes:

  1. Related routines are: WVSCHIPS, DCWCHIPS, AVHRRCHIPS, CORRELATE, EDITCORR, and NAVIGATE.

  2. The following table contains suggested threshold pixel values for screening out cloud image data. Any pixel value above the threshold value specified by THRVAL will not be used in the correlation process.

    
      	      | REFLECTANCE |      RADIANCE (AVHRR CHANNEL 2)
      SCALING     |     50%     | n11 = 168 | n12 = 167 | n14 = 164
      ------------|-------------|-----------|-----------|----------
      US Byte     |      200    |    129    |    128    |    126
      US I*2      |      500    |   1680    |   1670    |   1640
      US I*4      |      500    |   1680    |   1670    |   1640
      US Real     |       50    |    168    |    167    |    164
      Global Byte |       60    |     86    |     86    |     84
      Global I*2  |      510    |    325    |    323    |    317
      Global I*4  |     5010    |  16810    |  16710    |  16410
      Global Real |       60    |    178    |    177    |    174
    
    
    For example, 325 is the cloud threshold value to use for I*2 images from NOAA-11 channel 2 which have been calibrated and scaled with global scaling, and whose visible bands are radiance values. These reflectance threshold values have been computed by scaling a 50 percent reflectance value. The radiance threshold values have been computed by scaling a radiance value which is equivalent to a 50 percent reflectance value for AVHRR channel 2.

  3. Point identifiers within the tie point selection files must be unique. An error will result if merging of tie point selection files containing duplicate point identifiers is attempted.

  4. If SAVEDIR is specified, NAVIGATE will generate a data base file and plot file within the SAVEDIR directory. If SAVEDIR is not specified, these files will not be generated by NAVIGATE.