[GRASS-user] External Database and projections

[Blumentrath, Stefan]

Hi Lorenzo,

My suggestion is to not use PostGIS for big rasters, unless you have to, because you want to use the data in a specific application for example.
Loading raster to PG is a performace killer if you want to analyse the raster in GRASS (if that is possible at all)…

You can have the vector you want to calculate statistics on in PG. Load and reproject it to your DEM in GRASS, run your analysis and write the results (tables without geometry) back to PG and join them to your original vector map.
Do all spatial operations in GRASS (preferably raster based) meaning, convert vector to raster and use raster statistics (e.g. r.univar).

Cheers
Stefan

From: grass-user-bounces at lists.osgeo.org [mailto:grass-user-bounces at lists.osgeo.org] On Behalf Of Lorenzo Bottaccioli
Sent: 7. oktober 2015 12:40
To: grass-user at lists.osgeo.org
Subject: [GRASS-user] External Database and projections

Hello everyone,

I not very expert in this field and searching on the web didn't clarify my dubs.
I wanted to store a raster DEM and some vectors map in to an external DB, GRASS will use the DEM in order to calculate various raster map of solar radiation and need to store the again in the external DB. Than I'll use r.mapcal to do some calculation of on the raster maps and i'll use the vector map to extract this information. I don't need to store the calculation I just need to perform the calculation and use the results immediately.

My question is which could be a feasible solution for this? how do I manage the fact that the input raster and vector map can have different projection? What about if I want to define a default projection of the DB and convert the maps when I load them in the DB?

The DB will probably be Postgis, do you have any other suggestion?

Thanks a lot

Lorenzo
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