Support of --lat --lon for subsetting files in radar coordinates

[falkamelung]

Description of the desired feature

Subset.py did not support extracting from a file in radar coordinates a subset by giving lat/lon coordinates. This PR addresses this. This is useful to extract data for individual buildings after locating them in Google Earth or similar.

The accuracy of this approach is unclear. Because of this there is default buffer used which in the case I looked at was 20 pixels ( 'buf = 2 * np.max(np.abs([x_res, y_res]))' ). For this particular subsetting (radar coordinates, -lat -lon) this buffering is now switched off.

I previously observed that subsets don't always agree with the area you are asking which may be related to this buffer. I will observe and report on this later. If the buffer turns out to be a problem we may want to consider reducing or removing it.

This example demonstrates the improvement from buf=0 in the suggested code.

Are you willing to help implement and maintain this feature?

• Yes
• No