[GRASS-dev] Re: gis.m: resolution not preserved

[Maciej Sieczka]

Michael Barton napisa?(a):
> I posted a message on this over a week ago and got no reply.
> 
> <http://grass.itc.it/pipermail/grass-dev/2006-August/024866.html>
> 
> I also discovered this and thought it was a bug at first. But when I looked
> at the code (this new 'explore mode' was developed by Cedric Shock), I
> realized that it was intentional.
> 
> That is, it is dynamically changing resolution to speed display times as you
> zoom in and out.
> 
> I asked if this is what we wanted or not. There are advantages and
> disadvantages. It needs to be documented in any case, of course.

Michael,

OK as to "explore" mode. BUT, there is still another issue - that the
resolution is not preserved after zooming in gis.m in "normal" mode. Did
you try to reproduce it? Could you fix it?

I'm reffering to the following part of my email:

>> Start Grass in spearfish.
>>
>> # terminal:
>> g.region rast=slope -a
>>
>> # gis.m
>> add raster 'slope'
>> display it
>>
>> # gis.m CLI
>> g.region -g
>>
>> n=4928030
>> s=4913690
>> w=589980
>> e=609000
>> nsres=30
>> ewres=30
>> rows=478
>> cols=634
>>
>> # gis.m
>> zoom in/out a bit
>>
>> # gis.m CLI
>> g.region -g
>> n=4925065.04215
>> s=4921067.9817
>> w=593703.886256
>> e=599027.771749
>> nsres=30.05308609
>> ewres=30.07844911
>> rows=133
>> cols=177
>>
>> As you see, the resolution is not preserved.

>> I tried adding -a for g.region calls in mapcanvas.tcl and it seems to
>> solve the problem, but I'm not entirely sure which g.region calls really
>> require it, and which should be be left without it.

>> Also, it seems that rastnum.tcl and georect.tcl would require same fix (?).

Maciek