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Description
Description of the problem
In GMT<=6.3, when users access a remote grid but don't specify the grid registration (e.g., @earth_relief_01d
), the pixel-registrated grid is returned by default unless only the gridline-registrated grid is available.
The behavior has changed recently (GenericMappingTools/gmt#6710). The new behavior is well documented in https://docs.generic-mapping-tools.org/dev/datasets/remote-data.html#data-registration.
Optionally, you can append _g or _p to specifically get the gridline-registered or pixel-registered version (if they both exist). If reg is not specified then the behavior depends on whether you are making a plot or processing/extracting a subset of the data:
- For plots we will return the pixel-registered version unless only the gridline-registered file is available.
- For grid processing modules we will return the gridline-registered version unless only the pixel-registered file is available. We will also issue a warning since for calculations you should ideally know and specify exactly what you want.
If you do specify a specific registration and that version is not available you will get an error message.
In PyGMT, we provide the load_earth_relief
function to load the earth relief dataset into a xarray.DataArray object. When registration
is not specified, the function returns a pixel-registrated grid in GMT<=6.3, but will return a gridline-registrated grid in GMT 6.4, thus a few tests will fail.