Reports statistics for verification points
Computes statistics on errors in verification points. An option exists to calculate the amount of error in the verification points due to relief displacement. Another option exists to delete verification points if the residual magnitude for those points are greater than a specified limit.
- INTL
- Input tie point location file. Contains verification point coordinates.
- PIXSIZ(--)
- Pixel size. The pixel size int the output space of the image being verified. If NULL, the pixel size is read from the INTL header record. The unit of measure of the pixel size is given in the INTL header record.
- OUTPLOT(--)
- Output plot file. Name of the plot file containing the tie point id, the X and Y coordinates in the search image, and residuals errors. If MAXRES was specified and all points were removed, OUTPLOT will not be created.
- PRINT("TERM")
- Output destination. The destination of the verification report.
= --: No Report = 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".
- MAXRES(--)
- Maximum residual value. Maximum residual error in pixels that will be allowed for a point. If NULL, no editing will be performed and OUTTL and OUTFILE will be ignored.
- OUTTL(--)
- Output tie point location file. Contains the location points with residuals less than or equal to MAXRES.
- OUTFILE(--)
- Output file. Output file for verification points with residuals greater than MAXRES. This file has an extension of ";prt". If NULL, no output will be created for these points. If all points were kept, OUTFILE will not be created. Output for the other location points is specified by PRINT.
- INTL
- Input tie point location file. Contains verification point coordinates.
- INGRID
- Input grid files. The geometric mapping grids containing the inverse and forward polynomial mapping coefficients.
- PIXSIZ
- Pixel size. The pixel size in the input space followed by the pixel size in the output space. If only one value is entered, it is the pixel size in input space; the output pixel size is read from the INTL header record. The unit of measure of the output pixel size is given in the INTL header record. The input pixel size must be in meters.
- OUTPLOT(--)
- Output plot file. Name of the plot file containing the tie point id, the X and Y coordinates in the search image, and residuals errors. If MAXRES was specified and all points were removed, OUTPLOT will not be created.
- QUADNUM(0.0)
- TM quad number. The number of the TM quad used. QUADNUM should be zero if a full TM scene is used or if the imagery used is other than TM data. If a combination of TM quads are used, set QUADNUM to zero if the top or bottom half is used or set QUADNUM to any of the quads used if either the right or left half is used.
- SATHT(705000.0)
- Satellite height. The height of the satellite above the earth in meters.
= 822000.0: SPOT = 705000.0: Landsat 4, 5, 7 = 920000.0: Landsat 1, 2, 3
- INCANG(0.0)
- Incidence angle. The incidence angle of the SPOT HRV sensor in degrees. This value is found on SPOT summary sheets where L makes the angle positive and R makes the angle negative. The look angle of the first CCD detector is INCANG - 2.065. If using Landsat data, set INCANG to zero.
- FOVIEW(14.94)
- Field of view. The angle in degrees between the first and last detector (or sample) of a scanline.
= 4.13: SPOT = 14.94: Landsat
- PITCH(0.0)
- Pitch. Scanline pitch from nadir in degrees.
= 0.53 for SPOT Panchromatic = -0.53 for SPOT XS = 0.0 for Landsat
- DATUM(0.0)
- Reference datum. The reference elevation to which the relief displacement is adjusted to. The units of DATUM are specified in DATUNIT.
- DATUNIT("METERS")
- Datum unit. The unit of measure for DATUM.
= FEET: = METERS:
- PRINT("TERM")
- Output destination. The destination of the verification report.
= --: No Report = 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".
- MAXRES(--)
- Maximum residual value. Maximum residual error in pixels that will be allowed for a point. If NULL, no editing will be performed and OUTTL and OUTFILE will be ignored.
- OUTTL(--)
- Output tie point location file. Contains the location points with residuals less than or equal to MAXRES.
- OUTFILE(--)
- Output file. Output file for verification points with residuals greater than MAXRES. This file has an extension of ";prt". If NULL, no output will be created for these points. If all points were kept, OUTFILE will not be created. Output for the other location points is specified by PRINT.
Verification points in the tie point location file CHECK, as well as the residual error between the reference space and the registered image, are listed to the terminal. Also listed are the average line and sample residuals, the RMS errors in the line and sample direction, and the total RMS error in meters and in pixels.
Each verification point in the tie point location file CHECK is listed to the terminal. Also listed are the residual between the reference space and the registered image, the elevation of the point, and the residual error after the effects of relief are removed. Verification statistics (average and RMS errors) are first given for the residuals and then for the residuals adjusted for relief displacement. In this example, the imagery being verified is from the Landsat TM sensor.
Verification points in the tie point location file CHECK with residual magnitudes less than or equal to MAXRES are written to the tie point location file CHECK.PASS. They are also listed to the terminal along with the residual and RMS errors. The points with residual magnitudes greater than MAXRES are listed in the file ERROR;PRT in the same format as the points that were listed to the terminal.
Each verification point in the tie point location file CHECK with a residual magnitude less or equal to MAXRES is written to the tie point location file CHECK.PASS. They are also listed to the terminal along with the residual and RMS errors before and after relief effects are removed. The points with residual magnitudes greater than MAXRES are not output. All residual magnitude comparisons are done after relief effects are removed.
-NOREL subcommand:As each verification point from the tie point location file is read, its residual is calculated and reported. When all verification points have been processed, the average line and sample errors, the RMS error in the line and sample direction, the total RMS error in meters, and the total RMS error in pixels is reported.
If the MAXRES variable is set and if the residual for a point is less than or equal to MAXRES, that point will be written to a new tie point location file. In addition, the reporting of residual and RMS errors for these points will be separated from the points with residuals greater than MAXRES.
-RELIEF subcommand
The sensor specific parameters for relief displacement correction are reported to the user. Next, the tie point location file containing the verification points and the two geometric mapping grid files containing the inverse and forward mapping polynomial coefficients are opened and coefficients read. As each verification point is read, its residual is calculated. Next, the amount of relief displacement in the point is calculated by mapping the verification point to input (raw) space, computing the relief displacement, and mapping the corrected location back to output (registered) space. The residual error is then adjusted by the relief correction. The registered image location, the residuals between the reference space and the registered image, the elevation of the point, and the residual with relief effects removed are reported to the user. When all verification points have been processed--the average line and sample errors, the RMS error in the line and sample direction, the total RMS error in meters and the total RMS error in pixels are reported, first for the residuals, then for the residuals with relief displacement effects removed. Refer to the RELIEF module user's guide for the relief displacement algorithm.
The user should note three different processing methods as far as relief displacement is concerned. The -RELIEF subcommand should be used with rectified images--the relief displacement remains in the final image but the control or verification points are adjusted for these relief effects. Generally, if the RELIEF module was used in the rectification process, the -RELIEF subcommand should be used. If the imagery was differentially rectified, that is, relief displacements were removed from the output image pixel for pixel, producing an "ortho" image, use the -NOREL subcommand. The -NOREL subcommand should also be used if relief effects were ignored altogether.
The user should also note that the verification results are given with respect to the output image. Therefore, although relief displacement is an along-scan problem (for TM), the verification report may show a relief displacement in the line direction when the output image is rotated from the input image space.
If the MAXRES variable is set and if the residual for a point after removing relief effects is less than or equal to MAXRES, that point will be written to a new tie point location file.
The message displayed immediately preceding this message is the specific error encountered. Processing is terminated.
The pixel size of the output image is not specified in the tie point location (TPL) file header. Either edit the TPL file with EDITTIE or give the output image pixel size in PIXSIZ.
An error occurred allocating memory. Rerun, and if the error reoccurs, contact the system manager.
An output tie point location files was not specified. OUTTL must be specified if MAXRES is specified.
The specified file names for OUTFILE and PRINT were the same. Respecifiy one of the names and rerun.
o Select verification points with the TIEPTS module.
This will result in two tie point selection files, one
for the search coordinates (from the image being
verified) and one from the reference image or map.
o Convert map coordinates to line and sample coordinates
in the same output space frame as the registered
image using the TRANCOORD module if map coordinates
are used.
o Merge tie point selection files into a tie point
location file with the TIEMERGE module.
o Collect elevations for each verification point pair
using GETELEV or EDITTIE if relief displacement correc-
tion of verification points is desired and if eleva-
tions were not collected interactively during the veri-
fication point selection process.
o Run the VERIFY module.