[GRASS-user] EPSG 32633 and spatial resolution for hourly LST product from Copernicus

[Markus Metz]

On Tue, Sep 25, 2018 at 4:51 PM Nikos Alexandris <nik at nikosalexandris.net>
wrote:
>
> * Veronica Andreo <veroandreo at gmail.com> [2018-09-25 08:24:44 -0300]:
>
> >AFAIU, plate carree (lat long grid, no meters) is deprecated, and you
> >should use latlong instead. I had a similar issue with modis ocean color
> >products.
> >
> >Do you at least get the same number of row and columns that is described
by
> >gdalinfo when you import?
>
> No, it is 512^2 (see below) against
> ```
> g.regio -p
> ..
> rows:       3584
> cols:       8064
> ..
> ```
>
> Markus' hint, not *directly* on the netCDF file, rather on one of the
> layers:
>
> gdalinfo NETCDF:"g2_BIOPAR_LST_201606220100_GLOBE_GEO_V1.2.nc":LST
> Driver: netCDF/Network Common Data Format
> Files: g2_BIOPAR_LST_201606220100_GLOBE_GEO_V1.2.nc
> Size is 8064, 3584
> Coordinate System is:
> GEOGCS["unknown",
>     DATUM["unknown",
>         SPHEROID["Spheroid",6378137,298.2572326660156]],
>     PRIMEM["Greenwich",0],
>     UNIT["degree",0.0174532925199433,
>         AUTHORITY["EPSG","9122"]]]
> Origin = (-180.022321429103613,80.022321429103613)
> Pixel Size = (0.044642858207226,-0.044642858207226)
[...]
> Corner Coordinates:
> Upper Left  (-180.0223214,  80.0223214) (180d 1'20.36"W, 80d 1'20.36"N)
> Lower Left  (-180.0223214, -79.9776824) (180d 1'20.36"W, 79d58'39.66"S)
> Upper Right ( 179.9776872,  80.0223214) (179d58'39.67"E, 80d 1'20.36"N)
> Lower Right ( 179.9776872, -79.9776824) (179d58'39.67"E, 79d58'39.66"S)
> Center      (  -0.0223171,   0.0223195) (  0d 1'20.34"W,  0d 1'20.35"N)

apparently the center of the left-most column is -180, therefore forcing
the corner to -180 would shift the grid by half a cell.

>
> Import using r.in.gdal, _without_ any of `-l` or `-a` and then I get the
> closest to the reported spatial resolution. Else, with `-a`, for
> example, the spatial resolution is not as close to the "original" one.
> Makes sense?

what would be the output resolution and extends with r.in.gdal -a?
Generally r.in.gdal -a provides the best results.
>
> Better to cut off the west side (?):
> ```
> g.region raster=g2_BIOPAR_LST_201606220100_GLOBE_GEO_V1.2.nc_LST -pag
w=-180 e=180

this shifts the grid by half a cell to the east. The -a flag does not make
sense because 1) you want to force new extends, 2) there is no resolution
given for use with the -a flag.

Using g.region -pg defaults to g.region -g. Use either -p or -g.

Markus M
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-user/attachments/20181001/5a77d9a0/attachment.html>