"I'm trying to replace a dead WMS server in a GRASS GIS example. The options I have are:

Geographic (EPSG:4326)
NSIDC Sea Ice Polar Stereographic North (EPSG:3413)
Antarctic Polar Stereographic (EPSG:3031)
Web Mercator (EPSG:3857)
Which one would be the best choice for a general-purpose example, and why?"

sir @echoix ,
Which layer should I use for the WMS server

"I'm trying to replace a dead WMS server in a GRASS GIS example. The options I have are:

Geographic (EPSG:4326)

NSIDC Sea Ice Polar Stereographic North (EPSG:3413)

Antarctic Polar Stereographic (EPSG:3031)

Web Mercator (EPSG:3857)

Which one would be the best choice for a general-purpose example, and why?"

I would consider the EPSG:3857 (web Mercator) more general purpose, as it would look nice pretty much everywhere, that's why it's used in stuff like Google maps, even though it isn't a great choice for official usages due to its limitations.

Geographic too applies everywhere, but doesn't look as nice, as plotting the geographic coordinates (lat long) directly makes a distorted map.

Antarctic Polar Stereographic would probably be a good choice only for the region it applies to.

sir @echoix ,

Which layer should I use for the WMS server

Since I have no idea what the example looked like before with the working server, I think that if you choose an interesting one and location, and doing the screenshots with it and adapting the example for it, it would be fine. We'll let others here double check it was used properly and shows the correct usages of the module before merging.

Sorry for the delayed response—I had exams at my college and couldn't get back sooner.
1]Set the Region:
g.region n=7000000 s=5000000 w=-1000000 e=2000000 res=1000 -p
2]Fetch RGB Data from WMS Server:
r.in.wms layers=BlueMarble_ShadedRelief_Bathymetry
uri=https://gibs.earthdata.nasa.gov/wms/epsg3857/best/wms.cgi?
output=wms_blue_marble
and projection i have used is Web Mercator - EPSG:3857

3]Export Data to VTK Format:
r.out.vtk rgbmaps=wms_blue_marble.red,wms_blue_marble.green,wms_blue_marble.blue \ elevation=elevation.10m output=/tmp/out.vtk

I also incorporated slope_10@permanent to further enhance the analysis

Please suggest if there are any specific adjustments or additional features you'd like me to implement to enhance the example further

Describe the bug

The example here uses a dead WMS server.

grass/raster/r.out.vtk/r.out.vtk.html

Lines 95 to 109 in 5e27d1a

	<div class="code"><pre>
	#set the region
	g.region n=4926990 s=4914840 w=591570 e=607800 res=30 -p
	# using r.in.wms to create RGB data to get a satellite coverage
	r.in.wms layers=global_mosaic mapserver=http://wms.jpl.nasa.gov/wms.cgi \
	output=wms_global_mosaic
	# export the data to VTK
	r.out.vtk rgbmaps=wms_global_mosaic.red,wms_global_mosaic.green,wms_global_mosaic.blue \
	elevation=elevation.10m output=/tmp/out.vtk
	# visualize in Paraview or other VTK viewer:
	paraview --data=/tmp/out.vtk
	</pre></div>

Expected behavior

Docs replaced with a working example.

I think the closest I got to the current web servers are listed here https://nasa-gibs.github.io/gibs-api-docs/access-basics/#ogc-web-map-service-wms

Other

Other links: https://www.earthdata.nasa.gov/engage/open-data-services-software/earthdata-developer-portal/gibs-api https://neo.gsfc.nasa.gov/about/wms.php https://web.archive.org/web/20090703225229/http://wms.jpl.nasa.gov/wms.cgi

Set the region

g.region n=4926990 s=4914840 w=591570 e=607800 res=30 -p

Using r.in.wms to create RGB data to get a satellite coverage

r.in.wms layers=global_mosaic mapserver=https://gibs.earthdata.nasa.gov/wms/epsg4326/best
output=wms_global_mosaic

Export the data to VTK

r.out.vtk rgbmaps=wms_global_mosaic.red,wms_global_mosaic.green,wms_global_mosaic.blue
elevation=elevation.10m output=/tmp/out.vtk

Visualize in Paraview or other VTK viewer:

paraview --data=/tmp/out.vtk

To replace the WMS server in the r.in.wms example within the code snippet, you can substitute the mapserver URL with a different valid WMS server URL. For instance, you can use a server like NASA's GIBS (Global Imagery Browse Services) or any other relevant WMS server that provides data for your use case.