[GRASS-user] (re)projection question

[Helmut Kudrnovsky]

Helmut Kudrnovsky wrote
> 
> Ken Mankoff wrote
>> Hi Helmut,
>> 
>> On 2016-01-21 at 11:45, Helmut Kudrnovsky <

>> hellik@

>> > wrote:
>>> a quick internet search finds, e.g. 
>>> http://geotiff.maptools.org/proj_list/oblique_stereographic.html
>>> maybe a starting point.
>> 
>> I'd found that before, but thank you for sending the link again. I made
>> progress on re-reading it.
>> 
>>> for a correct Proj.4 string to create a location, it's best to ask in
>>> the
>>> Proj.4 ML.
>> 
>> The progress I made, unfortunately, makes me unsure if this is a proj4 or
>> a grass question. But I'm not sure.
>> 
>> I don't want to split this thread too much, but decided to try posting on
>> GIS.SE since both communities might see it there.
>> https://gis.stackexchange.com/questions/177763/how-to-define-proj4-string-for-grass
>> 
>> I'll post a resolution on this thread if I get an answer there.
> on GIS.SE you posted a link to your data; see there:
> 
> https://nsidc.org/data/docs/daac/nsidc0092_greenland_ice_thickness.gd.html
> 
> " Projection
> 
> All grids are in a polar stereographic projection with reference to the
> WGS84 ellipsoid. The standard parallel is 71°N, and the projection
> parallel (latitude of the center of the projection) is 90°N. The North
> Pole is the origin of the projection. The central meridian is 39°W."

quick test:

locatio wizzard -> create location by proj4 string:

+proj=sterea +datum=wgs84 +lat_0=70.5 +lon_0=40 

g.proj -j                                                                       
+proj=sterea
+lat_0=70.5
+lon_0=40
+k=1
+x_0=0
+y_0=0
+no_defs
+a=6378137
+rf=298.257223563
+towgs84=0.000,0.000,0.000
+to_meter=1

the location is created without any error; just adapt it for your need.




-----
best regards
Helmut
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