ANSI-C program: mkgrid.c
NAME
mkgrid - generate point list of coordinates of regular 2-D
grid
SYNOPSIS
mkgrid <plist> <nr> <naz> [r_step]
[az_step] [roff] [loff]
| <plist> | (output) point list of coordinates of regular 2-D grid (int) |
| <nr> | number of grid points in range |
| <naz> | number of grid points in azimuth |
| [r_step] | interval between points in range (default=10) |
| [az_step] | interval between points in azimuth (default=10) |
| [roff] | offset to starting range of segment to analyze (default: 0) |
| [loff] | offset to starting azimuth line of segment to analyze (default: 0) |
EXAMPLE
mkgrid testsite.plist 199 199 5 25 5 25
Generates a point list of coordinates on a regular grid. The SLC size is assumed to be 1000 range x 5000 azimuth pixels. The grid has 199 points in range and 199 points in azimuth direction, located at SLC coordinates (5,25),(10,25),...,(995,25),...,(995,4975).
INSTALLATION
Source code mkgrid.c in ./IPTA/src, executable version mkgrid in
./IPTA/bin
DESCRIPTION
In the IPTA point lists contain the coordinates (range and
azimuth pixel number relative to the reference SLC geometry) of
the selected points. Data at these points (SLC values,
interferogram values, ...) are stored in point data stacks with
each record corresponding to a different SLC or interferogram.
The point data stack of mask values contains for each point a
flag (0 or 1) which indicates if the data of a point are
considered (1) or not considered (0).
mkgrid supports the generation of point lists of points which are located on a regular grid. Such lists are of interest when converting "conventional" interferograms from the 2-D raster geometry to the vector data format used in the IPTA. In this transformation a sub-sampling is applied. This permits to strongly reduce the file sizes and strongly increases the efficiency of subsequent point list operations.
The grid coordinates to select are specified on the command line through the offset to the first point (in range and azimuth), the step between grid points (in range and azimuth), and the number of grid points in range and azimuth.
Point list coordinates selected with mkgird do generelly not correspond to point targets.
Instead of the full area of the SLC a sub-section can be selected.
Other programs to generate new point lists are image2pt, merge_pt, prox_pt, pwr_stat, and sp_stat.
Programs to validate existing point lists are qc_pt and expand_pt.
OPTIONS
none.
SEE ALSO
expand_pt, merge_pt, image2pt, prox_pt,
pwr_stat, qc_pt, sp_stat,
SLC_par, typedef_ISP.h, ipta.h.
© Copyrights for Documentation, Users Guide and Reference Manual by Gamma Remote Sensing, 2003.
UW, CW, TS, last change 20-Feb-2003.