[gdal-dev] Get max elevation on "squares"

[Luca Bertoncello]

Am 29.12.2021 um 10:30 schrieb Volker Wichmann:

Hi Volker

> I haven't followed the discussion in detail, but you could use
> 
> https://gdal.org/programs/gdallocationinfo.html
> 
> to read out the values from your resampled raster.

I did that. And got a little Python script to export the data as SQL for
a later import in a PostGIS database, so I can get the elevations by
country...

> The elevation differences between high and coarse resolution DEMs
> strongly depend on the relief in the area of investigation. So the
> differences between 25m and 5000m DEMs might be quite significant. Maybe

"Quite significant" means +/-30 meter in my tests...
Since every airplane has to hold _at least_ 600 meter over ground this
is really not a problem...

> better query the path on the high resolution and then smooth the profile
> afterwards (to keep min/max values for example).

This solution cannot work in my case, since I need the data as database
for use in my App. The pilot can decide every moment to change the route
and it's not always possible to get new data during the flight.
Importing 40GB data in the App is even not possible, of course...

Regards
Luca Bertoncello
(lucabert at lucabert.de)