Set region by extent?

Q&A PyGMT Q&A
1

Is there a way to set the region by the extent of a raster? I have a variety of TIF files that highlight different parts of a country, and would like to automatically resize region by the extent of the TIF file.

2

Not sure how it works in pyGMT, but in regular GMT you can do something like this to set the region:

region = $(gmt grdinfo <file.tif> -Ir)

Then instead of using an -R flag in your gmt grdimage or whatever it is, you use this “region” variable that has been defined from the tif extents.

e.g.:

gmt grdimage <tif> $reg ...

Hope that helps,
Jay

3

Or even simpler

-Rfile.tif

but that assuming that file is a GeoTIFF

4

The guys above have the right idea. Translating that to PyGMT, following Joaquim’s example, you would do something like fig.grdimage(grid="file.tif", region="file.tif").

The method by Jay will be more flexible, especially if you want nicely rounded coordinates. What you do in Python is

region = pygmt.grdinfo("file.tif", spacing="r")  # get exact extent
region = pygmt.grdinfo("file.tif", spacing="100r")  # get extent rounded to the nearest 100
fig.grdimage(grid="file.tif", region=region)