[gdal-dev] gdaldem aspect is grid-oriented

[Andrew C Aitchison]

On Fri, 25 Jun 2021, Michael Sumner wrote:

> Hello, we're using `gdaldem aspect` on polar grid products and we need to
> convert the grid-oriented directions to compass oriented ones,
> location-specific directions, where "compass north" is dependent on
> longitude.

I am curious; in the terminology of the British Ordnance Survey maps,
you are converting from "Grid North" but are you trying
to convert to "True North" or to "Magnetic North" ?

-- 
Andrew C. Aitchison					Kendal, UK
 			andrew at aitchison.me.uk