"ERROR: Unable to initialize coordinate transformation" when reprojecting from one CRS to another CRS in a different mapset

Question

I am trying to reproject a global raster (this: https://sedac.ciesin.columbia.edu/data/set/wildareas-v3-2009-human-footprint/data-download, I named it HFI) from Mollweide (its projection) to LAEA3035 and clip it to Europe. Usually, these are the steps I follow:

• I create a location with the same coordinate system of the file (in this case, I selected "choose the coordinate system from a referenced file", and used this raster as reference),

• switch to the Location LAEA3035, where I set the region and resolution: g.region -p res=1000 raster=myEuropeRaster

  projection: 99 (ETRS89_LAEA_Europe) zone: 0 datum: etrs89 ellipsoid: grs80 north: 6824829.90382694 south: 1385914.39679116 west: 944055.47446584 east: 7602904.43906583 nsres: 999.98446535 ewres: 999.97731861 rows: 5439 cols: 6659 cells: 36218301

• create a mask r.mask raster=myEuropeRaster

• run r.proj location=MOLL mapset=PERMANENT input=HFI output=HFI

It isn't working. First it throws two warnings:

WARNING: proj_trans() failed: acos/asin: |arg| >1.+1e-14

WARNING: proj_create() failed for '(null)'

and then an error:

ERROR: Unable to initialize coordinate transformation

This is the selected PROJ pipeline that appears:

Selected PROJ pipeline:
+proj=pipeline +step +inv +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000
+y_0=3210000 +ellps=GRS80 +step +proj=moll +lon_0=0 +x_0=0 +y_0=0
+ellps=WGS84

I searched online but couldn't find much information on how to solve this issue... I am using GRASS 7.8.6 on a server running Ubuntu 18.04.6 fro a Windows 10 machine.

Answer 1

I think that the problem is the extent of the original human footprint raster. It must be beyond the extent that is within the bounds of ETRS (EPSG:3035)

Here's how I worked it out:

• First I created a Mollweide location (as you already did), based on the downloaded human-footprint raster. And I imported that raster.

• Then I made another location (again, you already did this), based on EPSG:3035.

• Now I set the computational region to some "reasonable" bounds:

  micha@RMS$ g.region -ap
  projection: 99 (ETRS89-extended / LAEA Europe)
  zone: 0
  datum: etrs89
  ellipsoid: grs80
  north: 5600000
  south: 0
  west: 800000
  east: 8500000
  nsres: 1000
  ewres: 1000
  rows: 5600
  cols: 7700
  cells: 43120000

(Note that the resolution is set to match the original human footprint raster, 1000m.)

• Now I was able to reproject the Mollweide raster, while limited to the computational region.

HTH