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

[Gabriel Cotlier]

Dear Vero and Markus,

Thanks a lot for the guidance and help.

If I understood correctly:

I first have to import one layer when I select a location setting the
coordinate system of that layer to the mapset of GRASS (at the start).

Then I have to import all other layers to mapset using command "r.in.gdal
-a"

r.in.gdal -a input=C:\Users\Gabriel\Documents\layers\F121995.tif
output=F121995

Then I have to running "g.region" to set up the same extent to all layers
as follows:

g.region raster=F121995

and I got the layer processed and finished but the error did not went
way....

|i Inter-satellite calibration of DMSP-OLS Nighttime Stable Lights
WARNING: Operating on current region

|> Calibrating average visible Digital Number values
Regression coefficients: (-0.0515, 1.2293, -0.0038) | Associated R^2: 0.9178

360 degree EW extent is exceeded by 0.999827 cells
360 degree EW extent is exceeded by 1 cells

WARNING: As requested, timestamp transferring not attempted.
WARNING: No data base element files found

(Sun Jun 24 17:05:31 2018) Command finished (1 min 2 sec)


What could be doing wrong?
In addition I'm doing it for one layer here, is there a way to do it for
many layers at onces with command line or GUI dialog box?

Thanks a lot again.

Gabriel

On Sat, Jun 23, 2018 at 6:31 AM, Markus Metz <markus.metz.giswork at gmail.com>
wrote:

>
>
> On Sat, Jun 23, 2018 at 11:10 AM, Veronica Andreo <veroandreo at gmail.com>
> wrote:
> >
> > Hi,
> >
> > El sáb., 23 jun. 2018 4:35, Markus Metz <markus.metz.giswork at gmail.com>
> escribió:
> >>
> >>
> >>
> >> On Fri, Jun 22, 2018 at 10:34 PM, Veronica Andreo <veroandreo at gmail.com>
> wrote:
> >> >
> >> > Hi Gabriel,
> >> >
> >> > What you could do is import with r.in.gdal -a  that adjusts
> resolution for lat long maps [0]
> >>
> >> that will help to fix the resolution from 0.008333333300000 to
> 0.008333333333333, i.e. exactly 30 arc-seconds. The software used to create
> the raster data has stored the resolution with limited precision.
> >
> >
> > Right, I overlooked this
> >
> >> > and then (before the intercalibration step), set the region to one of
> the imported maps with g.region raster=yourmap
> >>
> >> you will then get a message like
> >> 360 degree EW extent is exceeded by 1 cells
> >>
> >> which is correct because the first and last column are duplicates. The
> cell centers cover -180, 180, and the EW extents regarding cell borders are
> E: 180:00:15E, W: 180:00:15W, grown by half a cell, i.e. 15 arc-seconds.
> >
> >
> > So, solution is to just use the data with the extra 15 arc-seconds in
> each side?
>
> yes, or chop off the first or last column: set the region to the raster,
> then modify the current region with g.region w=179:59:45W -p
> >
> > Of I want data to fit 180/-180, would r.region mymap e=180 w=180 help or
> will it change the data?
>
> this would modify the data because
> 1) the raster will be shifted by half a cell to the east
> 2) the cell size (ew resolution) will be changed
>
> Markus M
>
> >
> > Vero
>
>
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