[GRASS-user] CHELSA climate data set

[Helmut Kudrnovsky]

Veronica Andreo wrote
> Hi :)
> 
> JFYI, CHELSA v1.2 is out
> 
> 2017-02-07 15:43 GMT+01:00 Markus Neteler <

> neteler@

> >:
> 
>> On Tue, Feb 7, 2017 at 3:32 PM, Markus Metz
>> <

> markus.metz.giswork@

> > wrote:
>> [...]
>> > Compared to GMTED, CHELSA extents further south to 90:0:0.5S which
>> conforms
>> > to the GMTED grid geometry. For CHELSA, however gdalinfo reports
>> > Pixel Size = (0.008333333300000,-0.008333333300000)
>> > while for GMTED, gdalinfo reports
>> > Pixel Size = (0.008333333333333,-0.008333333333333)
>> >
>> > The reason for the slightly smaller pixel size is most probably reduced
>> > floating point precision during creation of the CHELSA data.
>>
>> from personal comm.:
>> They are currently investigating where the precision is cut in their
>> workflow (the upcoming V1.2 shall come with a related correction).
>>
> 
> Unfortunately they have not corrected the precision issue...
> 
> gdalinfo CHELSA_temp_2_1979-2013_V1.2_land.tif
> Driver: GTiff/GeoTIFF
> Files: CHELSA_temp_2_1979-2013_V1.2_land.tif
> Size is 43200, 20880
> [...]
> Origin = (-180.000138888850017,83.999860415150010)
> Pixel Size = (0.008333333300000,-0.008333333300000)
> 
> Corner Coordinates:
> Upper Left  (-180.0001389,  83.9998604) (180d 0' 0.50"W, 83d59'59.50"N)
> Lower Left  (-180.0001389, -90.0001389) (180d 0' 0.50"W, 90d 0' 0.50"S)
> Upper Right ( 179.9998597,  83.9998604) (179d59'59.49"E, 83d59'59.50"N)
> Lower Right ( 179.9998597, -90.0001389) (179d59'59.49"E, 90d 0' 0.50"S)
> Center      (  -0.0001396,  -3.0001392) (  0d 0' 0.50"W,  3d 0' 0.50"S)
> Band 1 Block=43200x1 Type=Float32, ColorInterp=Gray
>   NoData Value=-99999
> 
> best,
> Vero

yes, AFAIK they're still working on it.

tested here ver.1.2 with r.in.gdal trunk and

-a
    Auto-adjustment for lat/lon
    Attempt to fix small precision errors in resolution and extents

it seems to give good results.




-----
best regards
Helmut
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