[postgis-users] loading raster colour heatmap data or converting to a shape file

Pierre Racine Pierre.Racine at sbf.ulaval.ca
Fri Feb 5 10:27:04 PST 2016

This all depends on the kind of operations you want to do... Some might be easier keeping rasters as raster. Others are easier if you convert everything to vector.

You can easily convert raster loaded in PostGIS to vector using ST_DumpAsPolygons(). The reverse operation is done through a mix of ST_AsRaster() and ST_Union().


> -----Original Message-----
> From: postgis-users [mailto:postgis-users-bounces at lists.osgeo.org] On
> Behalf Of dave.potts at pinan.co.uk
> Sent: Friday, February 05, 2016 4:13 AM
> To: postgis-users at lists.osgeo.org
> Subject: [postgis-users] loading raster colour heatmap data or converting to
> a shape file
> Hi list,
> I have some heat map files which I want to do some spatial analyisis on.
> I am wondering what the best way to proceed.  I admin that I have never
> used the raster part of postgis before.
> I have two choices
> 1. Convert the raster files to shape files and load the shape files in to
> postgis.
> 2. Load the raster files and have a play with some of the raster operators.
> Has anybody got any suggestions as to the best way to proceed?
> The heatmap are geotiff files and are correctly geoferenced and can be any
> colour that I choose.
> As a side issue are there any colour combinations that  are easier to convert
> form raster to vector for  example would a black/white image digitise better
> than an image coloured in many different  shades of orange?
> regards
> Dave.

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