[GRASS-user] Rectify error / maximum number of GCPs?

[Markus Neteler]

On Sat, Mar 21, 2009 at 1:21 AM, Benjamin Deschamps <bdesc100 at gmail.com> wrote:
>
> I am trying to georectify RADARSAT-2 imagery in GRASS 6.4.0RC3 (Mac OS 10.5).
> The imagery is accompanied by 350 GCPs. When using the GUI georectify tool I
> get the following error when I click on the "start georectifying" button:
>
> can't read "xy(51)": no such element in array
> can't read "xy(51)": no such element in array
>    while executing
> "$xy($gcpnum) insert     0 "[lindex $fields 0] [lindex $fields 1]""
>    (procedure "GRMap::get_gcp" line 34)
>    invoked from within
> "GRMap::get_gcp"
>    (procedure "GRMap::gcpwin" line 119)
>    invoked from within
> "GRMap::gcpwin"
>    (procedure "GRMap::refmap" line 33)
>    invoked from within
> "GRMap::refmap"
>    ("uplevel" body line 1)
>    invoked from within
> "uplevel \#0 $cmd"
>    (procedure "Button::_release" line 18)
>    invoked from within
> "Button::_release .grstart.mf.frame.start.a"
>    (command bound to event)
>
>
> Is there a limit of 50 GCPs?

It looks like that. But I don't know why (I'm not the author of this code):

grep 51 gui/tcltk/gis.m/georect*
gui/tcltk/gis.m/georect.tcl:    for {set gcpnum 1} {$gcpnum < 51 } {
incr gcpnum } {
gui/tcltk/gis.m/georect.tcl:            if {$gcpnum == 51} {break}
gui/tcltk/gis.m/georect.tcl:    for {set gcpnum 1} {$gcpnum < 51 } {
incr gcpnum } {
gui/tcltk/gis.m/georect.tcl:    for {set gcpnum 1} {$gcpnum < 51 } {
incr gcpnum } {
gui/tcltk/gis.m/georect.tcl:            for {set gcpnum 1} {$gcpnum <
51 } { incr gcpnum } {
gui/tcltk/gis.m/georect.tcl:    for {set gcpnum 1} {$gcpnum < 51 } {
incr gcpnum } {

You could just edit the file (it is in the GRASS installation somewhere)
and replace 51 to say, 501 and try again.

Please report if that works for you.

Markus