Questions tagged [postgis-raster]

PostGIS Raster is a PostGIS data type for storing and analyzing raster data.

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31
votes
3answers
11k views

Poor performance with storing large rasters in PostGIS and visualising in QGIS

my question concerns the use and performance of several software tools in conjunction, namely PostgreSQL, PostGIS, QGIS, and GDAL. I'm a long-time ArcGIS, Python, and R user who is interested in ...
14
votes
2answers
4k views

Downloading raster data into python from postgis using psycopg2

I have raster data in a postgres table that I want to get into python as a numpy array. I am using psycopg2 to connect to the db. I am able to download the data but it comes back as a string (probably ...
3
votes
1answer
602 views

How to speed up raster/map algebra in PostGIS?

I am testing map algebra with PostGIS (2.1 with PostgreSQL 9.3) on two images, and found it to be rather slow. For example, dividing two images of 7200 * 3600 pixels took 110 ~ 120s on a desktop with ...
6
votes
1answer
2k views

Uploading raster format (*.tif) to PostGIS through raster2pgsql

I'm new to PostGIS and raster file format. I'm currently working on NetCDF files and I want to import them into PostGIS through curl command line tool but its failed for me. So I jumped on to GDAL v1....
3
votes
1answer
2k views

How to view a postgis raster query in QGIS

I have successfully loaded a large number of .asc images (>2800 200x200 tiles) into a Postgres table with PostGIS 2.1 support. The new table appears in QGIS's DB Manager and I can add the whole image ...
6
votes
1answer
2k views

Converting a PostGIS raster back to vector

Is it possible to convert a PostGIS raster back to a line? I'd like to generalize some vector data by converting it to raster and altering the cellsize to fix 'gaps' in the vector connectivity. Once ...
3
votes
1answer
200 views

PostGIS raster calculate average slope of 3x3 neighborhood around a geometry point

I have two tables corners_final (vector point data) dem_slope (1ft slope DEM, calculated in degrees) With this simple query I am able to extract the slope value that intersects a given point SELECT ...
3
votes
1answer
820 views

Replacing pixel value by lookup table using PostGIS?

I was wondering if it is possible to write a PostgreSQL statement to replace the value of each pixel in an input PostGIS-raster with a value obtained from a look up table. For example, suppose I have ...
3
votes
1answer
3k views

Connecting PostGIS raster data to GeoServer

The data I have used is DEM. It creates a table and has 2 columns in PostGIS. Is it necessary to create a new table again and follow the configuration process as mentioned in the Image Mosaic JDBC ...
2
votes
0answers
175 views

Error Quantifying Land Cover Classes by Polygon in PostGIS

I am trying to ultimately calculate proportion of land cover types by polygon in PostGIS, so starting using st_valuecount to get counts of pixels with different land cover types. The data are pretty ...
2
votes
0answers
524 views

I am getting error in PostGIS 'function st_clip(raster, integer, geometry) does not exist'? [closed]

I have to find the count of the number of pixels in a given band of a clipped raster. For clipping, I am using ST_clip(). Through clip function raster is clipped with a polygon. I am getting ...
1
vote
1answer
374 views

PostGIS: ST_Clip problem with area which oversteps the raster

Hello all the PostGIS wizards! I want to programmatically clip raster with bounding box which is overstepping the border of raster. Ok, i can do it with ST_Clip, but the problem is that ST_Clip only ...
1
vote
1answer
1k views

ST_AsRaster for polygon

Having a hard time to get a raster from a polygon ST_AsRaster(ST_Buffer(ST_GeomFromText('POLYGON((-30 40, -20 30, -25 20, -23 10, -30 40))', 4326), 50),ARRAY['8BUI'],ARRAY[118]); This line is giving ...
1
vote
1answer
366 views

Why is pgraster much slower?

This is a follow up question to my other question: How to speed up raster/map algebra in PostGIS? I am much attracted to the way how PostGIS handle vectors and rasters in an interoperable manner. A ...
1
vote
1answer
951 views

Is there a tool to shrink/grow raster data edge by n pixels

Looking for an open source tool to grow/shrink raster edge by n pixels. I noticed Grass has r.grow but hoping there might be a way to do it with GDAL, PostGIS or python library. More information: I ...
0
votes
0answers
38 views

Schema error while uploading raster in PostgreSQL

Tried many ways A. import os import subprocess from subprocess import PIPE, run db_name = 'agro_dss' db_host = 'localhost' db_port = '5432' db_user = 'postgres' db_password = 'imd123#' os.environ['...
0
votes
1answer
345 views

PostGIS intersect query: Raster footprints of multiple high resolution GeoTIFF's or not? [closed]

I have multiple (381) high resolution GeoTIFF's (2x2 meter resolution, 1 band, 700 MB each) that I somehow want to upload to a PostGIS-server to be able to run ST_intersects or ST_3Dintersects queries ...
0
votes
0answers
27 views

PostGIS Rasters now loading differently with QGIS 3.14+

In QGIS version 3.10 when loading in a raster from my PostGIS DB it worked fine and when hoovering over for info gave this message Now with version 3.16(anything over 3.14) I am getting this when on ...