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Questions tagged [st-difference]

The tag has no usage guidance.

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24 views

Function in R to get difference between two sets of polygons comparable in speed to QGIS

I have two very large polygon shapefiles for which I need to calculate the difference between the two shapefiles. One is a shapefile of forest polygons, the other is a shapefile of road polygons. I ...
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0answers
54 views

Uploading overlapping contours into PostgreSQL?

I've got 100+ shapefiles of contours with the following fields: class (text) altitude (double) geom (geometry) And I need to upload them into a single table in PostgreSQL. Now, I've managed to ...
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1answer
83 views

st_difference (erase overlapped feature) line from polygon

I have two layers. One is MultiLineString and the other is MultiPolygon. I am trying to erase lines that are on the polygon feature With QGIS difference tool, it worked just fine This is my code and ...
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3answers
182 views

Increase spatial query performance (st_difference)

I have two link tables one is 9029 rows (and let's say this table is A) and the other is 11698 rows (and this table is B) the both tables are road link and A is for tunnel link and B is road link ...
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0answers
163 views

ESRI Polygon cutouts (neg. space) become multiple layers in PostGIS

I have a single MULTIPOLYGON from ESRI ArcGIS with 10,000+ sub-polygons in a Shapefile, some having > 1.4 million vertices. I'm importing the data into PostGIS (ogr2ogr or shp2pgsql, same results) so ...
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1answer
132 views

Bringing two lines together and getting their difference

In the photo there are two lines that are parallel to each other. I want to bring them at same coordinates and carry out the difference between them, which will be the small part of red line from the ...
4
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0answers
56 views

ST_Difference() PostGIS returns weird results [duplicate]

I'm trying to use the postgis's st_difference() function, but with no luck. I have a layer of polygons A And a layer of Polygons B What I want to achieve is this (created with QGIS algorithm): ...