[GRASS-user] question on i.nightlights.intercalibration code

[Gabriel Cotlier]

 Dear Nikos,
Thanks a lot for the explanation.
Regards,
Gabriel


On Fri, Jul 6, 2018 at 4:55 AM, Nikos Alexandris <nik at nikosalexandris.net>
wrote:

> * Gabriel Cotlier <gabiklm01 at gmail.com> [2018-07-05 18:28:30 -0300]:
>
> Dear Markus,
>> Thanks a lot for the explanation. For some reasoner every time I try to
>> run
>> g.region I can's and I got this pop up dialog box as in the figure below,
>> and apparently g.region does not run...
>> How could be possible to solve it?
>> Thanks a lot again.
>> Best regards,
>> Gabriel
>>
>
> It is friendly, from the Operating System's side, trying to help in
> handling GRASS GIS' .region files. Obviously, though, not required in
> this case. It looks like you would need to search for how to tell the
> Operating System to ignore .region files.
>
>
> Thanks for the summary. In a shorter version:
>
> r.in.gdal -a input=Fxy # for all images
> g.region raster=Fx     # only once
> i.nightlights.intercalibration ...
>
> or
>
> r.in.gdal input=Fxy  # for all images
> r.region -a map=Fxy  # for all images
> g.region raster=Fx   # only once
> i.nightlights.intercalibration ...
>
>
> More detailed
>
> # import *all* images with
> r.in.gdal -a input=Fxy
>
> (
> This is the import command for one image. All related images have to be
> imported like that. Easier via a for loop, i.e., under Linux, and within
> from the directory where all images reside,
>
> for RASTER in Fxy*.tif ;do r.in.gdal -a input=$RASTER output=$(basename
> $RASTER .tif) ;done
>
> This is a somewhat more elaborated one-line command. This is easily
> to be done through the GUI: you can select a "directory" from
> inside which to import images.
>
> I recall also a related post from Helmut, on how to approach this in
> Windows, in the command line.
> )
>
> # set the computational region
> g.region raster=Fxy
>
> # inter-calibrate your images
> i.nightlights.intercalibration ...
>
>
> What about r.region?
>
> First, some clarifications:
>
> - `r.in.gdal` imports a raster/image in to the GRASS GIS data base, by
>  converting it in a GRASS GIS native raster format. It also sets the
>  extent and resolution of a raster/image.
>
> - `r.region` works directly on the images extent. It is a tool to modify
>  the raster's metadata directly.
>
> - `g.region` set the computational region for a GRASS GIS Location/Mapset,
> which is then what almost all raster modules will consider as the
> "active" region to perform computations on.
>
>
> The `r.region -a` would come in play in case you have already imported
> the image without the `-a` option for `r.in.gal`, say Fxy. and then you'd
> want to fix the pixel size
> imprecision issue that Markus pointed out.
>
> That would be:
>
> r.in.gdal input=Fxy  # for all images
> r.region -a map=Fxy  # for all images
> g.region raster=Fxy  # only once!
> i.nightlights.intercalibration  # for all related images
>
>
> Since you are re-importing the images, using `r.in.gdal -a`, you don't
> need to employ r.region at any step.
>
>
> Finally,
>
> if the above won't work, then there be something else that causes the
> problem.
>
> Please, do not hesitate to write back about this. We all have our own way
> of learning. If whatever is discussed so far, is still not clear enough,
> then let us try one more time: I will try to learn/improve how to better
> communicate, in written form, these command instructions. And you could
> try to
> go through what is written one more time, and take notes, one-by-one.
>
> Best, Nikos
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-user/attachments/20180706/2015a867/attachment.html>