Hi
I’m using GRASS GIS 6.4.0 (stable version) in Windows (because my Univ made a few addaptations and modules to be used in my final project) but I’m having some difficulties in using Georectify tool.
After I select 3 points, I press Recalculate RMS Error (and I get the image that I have attached to the email). THis is impossible to have 0,0 as error (in this case). and I got:
POINTS file <D:\data\Area\scale\group\ai\POINTS> saved
But, then I press Georectify and It freezed all Interfaces and I got, in the top of each one, (Not Responding)… I waited 10 minutes (it sould take less than that). And still not responding…
In the Windows task manager i.rectify is running with 3,420 and Python 47,000
And If I go to my mapset folder I see that the files were created.
Is this normal/expected? What might be happening? Because this happened more than once…as a matter of fact, all the times that I tried with these images.
My active mapset is the same as my source image (in order to save the images in the source mapset).
Another question:
If my source (to be georreferenced) data has a resolution of 10 meters and my target (already georreferenced) as 30 meters resolution and my active mapset is 10 meters… Georreferenced output will have which spatial resolution?
Thanks
Jenny
(attachments)
On Sat, Nov 27, 2010 at 12:23 PM, Jenny Turner
<jennyturner1980@gmail.com> wrote:
Hi
I'm using GRASS GIS 6.4.0 (stable version) in Windows (because my Univ made
a few addaptations and modules to be used in my final project) but I'm
having some difficulties in using Georectify tool.
After I select 3 points, I press Recalculate RMS Error (and I get the image
that I have attached to the email). THis is impossible to have 0,0 as error
(in this case).
No, because the RMS errors will always be zero if the number of points
is equal to the minimum number of points required for the selected
order, here 3 points for first order.
POINTS file <D:\data\Area\scale\group\ai\POINTS> saved
But, then I press Georectify and It freezed all Interfaces and I got, in the
top of each one, (Not Responding)... I waited 10 minutes (it sould take less
than that). And still not responding...
Ho long does georectification take if you use i.rectify directly from
the source location/mapset?
Another question:
If my source (to be georreferenced) data has a resolution of 10 meters and
my target (already georreferenced) as 30 meters resolution and my active
mapset is 10 meters.. Georreferenced output will have which spatial
resolution?
If you choose 'clip to computational region in target location', the
computational region in the target location+mapset will be used.
Otherwise i.rectify estimates the minimum target region required to
hold the source image and estimates a resolution corresponding to the
image resolution.
Markus M