ANSI-C program: merge_pt.c
NAME
merge_pt - merging of point lists
SYNOPSIS
merge_pt <plist_tab> <plist_out>
<N_min> <r_tol> <az_tol>
| <plist_tab> | (input) text file containing names of input point lists
and masks (each line contains one point list and optionally one mask name) |
| <plist_out> | (output) point list derived from merging input point lists |
| <N_min> | occurance number minimum to include a point to the output list |
| <r_tol> | range position tolerance for counting occurances |
| <az_tol> | azimuth line tolerance for counting occurances |
EXAMPLE
merge_pt testsite.plist_tab testsite.plist 1 0 0
Generates a point list of all the points of all the provided input point lists indicated in the point list table. Masks indicated together with the point lists are considered.
merge_pt testsite.plist_tab testsite.plist 5 1 3
Generates a point list of coordinates by merging the point lists indicated in the point list table. Masks indicated together with the point lists are considered. Points which appear in at least 5 of the input point lists are written to the output "merged" point list.
INSTALLATION
Source code merge_pt.c in ./IPTA/src, executable version merge_pt
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).
merge_pt supports the merging of multiple point lists into a single output point list.
One use of merge_pt is the combination of complementary point lists. This can be point list covering different areas of an image or point lists with different characteristics, e.g. one list with points corresponding to point targets and one list with points representing a sub-sampling grid for a 2-D differential interferogram.
Another important use is the merging of multiple point lists which are all indicating candidates for "good points", as for example obtained by applying sp_stat to different co-registered SLC. In such a case there may be for example 8 input lists and points which occur at least 5 times are included to the output list. This permits to include a temporal criteria together with the point target criteria used by sp_stat.
The input point lists and the corresponding mask files need to be provided in the point list table, an ascii text file which contains on each line one point list filename and optionally the corresponding mask filename.
Example of a point list table:
| testsite.list1 | testsite.mask1 |
| testsite.list2 | |
| testsite.list3 | testsite.mask3 |
| ... | ... |
| testsite.list8 | testsite.mask8 |
In the occurance counting a tolerance in range and azimuth is taken into account.
To include all points of all input point lists the minimum occurrance number is set to 1 and the range and azimuth line tolerance values to 0.
In the output list a certain point (coordinate) occurs at most once.
Programs to generate new point lists are image2pt, mkgrid, pwr_stat, prox_pt, and sp_stat.
OPTIONS
none.
SEE ALSO
image2pt, mkgrid, prox_pt,
pwr_stat, 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.