1

I'm trying to evaluate mean temperatures for the distribution area of European fish species. Therefore, I downloaded the E-OBS data set for mean annual temperature in Europe (0.25 deg. reg., "TG"), loaded it into QGIS and clipped the raster using a polygon shape as a mask. I did not alter the projection, but I added the command --config GDALWARP_IGNORE_BAD_CUTLINE YES to the console: Clipping window After that, I used the value tool to extract pixel values for random locations of the newly clipped layer and noticed, that strongly deviate from the original data. Unfortunately, I can't post more that 2 links here, but the original data is in °C values and the clipped layer has values in the magnitude of plus-minus several hundreds.

Is there an obvious flaw in my workflow I'm not seeing?

edit: Text fraction of the Layer obtained from Layer properties->Metadata->Properties:

D:/GoogleDrive/Sonstiges/GIS/tg_0.25deg_reg_1950-1964_v15.0.nc/tg_0.25deg_reg_1950-1964_v15.0.nc latitude#long_name=Latitude values latitude#standard_name=latitude latitude#units=degrees_north longitude#long_name=Longitude values longitude#standard_name=longitude longitude#units=degrees_east NC_GLOBAL#Conventions=CF-1.4 NC_GLOBAL#Ensembles_ECAD=15.0 NC_GLOBAL#history=Wed May 31 15:20:56 2017: ncks -a -d time,0,5478 tg_0.25deg_regular_1.nc tg_0.25deg_reg_1950-1964_v15.0.nc Wed May 31 15:19:16 2017: ncks -a --mk_rec_dmn time tg_0.25deg_regular.nc tg_0.25deg_regular_1.nc NC_GLOBAL#NCO="4.6.2" NC_GLOBAL#References=http://www.ecad.eu\nhttp://www.ecad.eu/download/ensembles/ensembles.php\nhttp://www.ecad.eu/download/ensembles/Haylock_et_al_2008.pdf NETCDF_DIM_EXTRA={time} NETCDF_DIM_time_DEF={5479,4} NETCDF_DIM_time_VALUES={0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,[...]

  • Please edit and provide either gdalinfo output for the input raster or (in QGIS) the text in Layer properties->Metadata->Properties. – user2856 Aug 23 '17 at 7:14
  • Is there a specific part of the text you're interested in? The entire length is extremely long. – Ruben Aug 23 '17 at 7:38
  • I'm looking for a scale factor in the NC metadata, but also the basic raster properties. Is there a direct link to the original dataset /metadata etc? – user2856 Aug 23 '17 at 7:50
  • there is: ecad.eu/download/ensembles/downloadchunks.php It is the 0.25 deg. regular grid, Version 15.0, 1950-1964, TG file. – Ruben Aug 23 '17 at 7:51
  • Are the pixels shifted relative to the original dataset? – Logan Byers Aug 23 '17 at 13:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.