<div dir="ltr"><div>Ok - just to clear this up and shut down this thread. It turns out it is EPSG:3411 but was reported as 3413. I can import (with -o) into a 3411 location, and then reproject.</div><div><br></div><div>Cheers,</div><div><br></div><div> -k.<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Jul 25, 2021 at 8:45 PM Ken Mankoff <<a href="mailto:mankoff@gmail.com">mankoff@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Hi Stefan,</div><div><br></div><div>Thanks for the hint. I often use '-o'. In this case after discussion with the data provider it turns out that it was not EPSG:3413 but instead some custom projection, even though part of the NetCDF file reported EPSG:3413 in the metadata.</div><div><br></div><div>Unfortunately r.import does not work. I get the errors below. Given the 0..3..6..9... it appears to import something, but no raster exists when the command finishes.<br></div><div><br></div><div>r.import input=NetCDF:file.nc:surface output=surface<br>WARNING: Datum <unnamed> not recognised by GRASS and no parameters found<br>WARNING: Projection of dataset does not appear to match current location.<br><br>Location PROJ_INFO is:<br>name: WGS 84 / NSIDC Sea Ice Polar Stereographic North<br>datum: wgs84<br>ellps: wgs84<br>proj: stere<br>lat_0: 90<br>lat_ts: 70<br>lon_0: -45<br>x_0: 0<br>y_0: 0<br>no_defs: defined<br>init: EPSG:3413<br><br>Dataset PROJ_INFO is:<br>name: unnamed<br>a: 6378273<br>es: 0.006693883000000017<br>proj: stere<br>lat_0: 90<br>lat_ts: 70<br>lon_0: -45<br>x_0: 0<br>y_0: 0<br>no_defs: defined<br><br>ERROR: datum<br><br>WARNING: Datum <unnamed> not recognised by GRASS and no parameters found<br>WARNING: Datum <unnamed> not recognised by GRASS and no parameters found<br>Importing raster map <surface>...<br>0..3..6..9..12..15..18..21..24..27..30..33..36..39..42..45..48..51..54..57..60..63..66..69..72..75..78..81..84..87..90..93..96..99..100<br>ERROR: Unable to open element file <windows> for <tmp.r.import.3257873@PERMANENT><br>ERROR: Unable to get reprojected map extent</div><div><br></div><div><br></div><div> -k.<br></div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Jul 24, 2021 at 2:19 PM Stefan Blumentrath <<a href="mailto:Stefan.Blumentrath@nina.no" target="_blank">Stefan.Blumentrath@nina.no</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hei Ken,<br>
<br>
Did you try the -o flag ("Override projection check (use current location's projection)<br>
Assume that the dataset has same projection as the current location")?<br>
<a href="https://grass.osgeo.org/grass78/manuals/r.external.html" rel="noreferrer" target="_blank">https://grass.osgeo.org/grass78/manuals/r.external.html</a><br>
As the error message suggests?<br>
<br>
If you are sure that projections in fact match, a mismatch in CRS description can be overridden that way, without modifying the input file.<br>
<br>
Alternatively, you can use r.import to reproject while converting to GRASS format or you create a new location...<br>
<br>
Cheers<br>
Stefan<br>
<br>
<br>
-----Original Message-----<br>
From: grass-user <<a href="mailto:grass-user-bounces@lists.osgeo.org" target="_blank">grass-user-bounces@lists.osgeo.org</a>> On Behalf Of Ken Mankoff<br>
Sent: fredag 23. juli 2021 19:33<br>
To: GRASS user list <<a href="mailto:grass-user@lists.osgeo.org" target="_blank">grass-user@lists.osgeo.org</a>><br>
Subject: [GRASS-user] Cannot read NetCDF with 'semi_major_axis' or 'inverse_flattening'<br>
<br>
Hello list,<br>
<br>
I have been given an updated NetCDF file - everything is the same as the old version except there are two new attributes in the 'mapping' variable:<br>
<br>
char mapping ;<br>
mapping:geoid = "eigen-6c4" ;<br>
mapping:grid_mapping_name = "polar_stereographic" ;<br>
mapping:latitude_of_projection_origin = 90. ;<br>
mapping:standard_parallel = 70. ;<br>
mapping:straight_vertical_longitude_from_pole = -45. ;<br>
mapping:semi_major_axis = 6378273. ;<br>
mapping:inverse_flattening = 298.27940504282 ;<br>
mapping:false_easting = 0. ;<br>
mapping:false_northing = 0. ;<br>
mapping:_Storage = "contiguous" ;<br>
<br>
<br>
Specifically:<br>
mapping:semi_major_axis = 6378273. ;<br>
mapping:inverse_flattening = 298.27940504282 ;<br>
<br>
When I try to load this file with:<br>
<br>
r.external source=netCDF:file.nc:surface output=surface<br>
<br>
I get this error:<br>
<br>
WARNING: Datum <unnamed> not recognised by GRASS and no parameters found<br>
ERROR: Projection of dataset does not appear to match current location.<br>
<br>
Location PROJ_INFO is:<br>
name: WGS 84 / NSIDC Sea Ice Polar Stereographic North<br>
datum: wgs84<br>
ellps: wgs84<br>
proj: stere<br>
lat_0: 90<br>
lat_ts: 70<br>
lon_0: -45<br>
x_0: 0<br>
y_0: 0<br>
no_defs: defined<br>
init: EPSG:3413<br>
<br>
Dataset PROJ_INFO is:<br>
name: unnamed<br>
a: 6378273<br>
es: 0.006693883000000017<br>
proj: stere<br>
lat_0: 90<br>
lat_ts: 70<br>
lon_0: -45<br>
x_0: 0<br>
y_0: 0<br>
no_defs: defined<br>
<br>
ERROR: datum<br>
<br>
In case of no significant differences in the projection definitions, use the -o flag to ignore them and use current location definition.<br>
Consider generating a new location from the input dataset using the 'location' parameter.<br>
<br>
<br>
If I remove thos two attributes (semi_major_axis and inverse_flattening) with:<br>
<br>
ncatted -O -h -a semi_major_axis,mapping,d,l,6378273 -a inverse_flattening,mapping,d,f,298.27940504282 <a href="http://file.nc" rel="noreferrer" target="_blank">file.nc</a> <a href="http://foo.nc" rel="noreferrer" target="_blank">foo.nc</a><br>
<br>
And then try to read in the data, it works.<br>
<br>
Is there some reason that those two attributes make it difficult to load the data in GRASS? Is there a better work-around than removing them? The documented projection of the data has not changed, only some of the metadata.<br>
<br>
Versions:<br>
gdal 3.0.4<br>
grass 7.8.2<br>
<br>
Thank you,<br>
<br>
-k.<br>
<br>
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