Questions tagged [differences]
A "difference" operation is a geoprocessing operation that completely removes one overlapping polygon and the intersection of that polygon from the other. It uses one polygon to "take a bite" out of another.
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How can I detect which geometries degenerate into lines on running QGIS difference tool
I run difference tool between two area layers.
Sadly, it failed with "Could not add feature with geometry type MultiLineString to layer of type MultiPolygon"
It seems that some of geometries ...
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Splitting polygon that is result of difference function between two polygons in QGIS
So I have this polygon (picture 1) that will be used to make its bounding geometry as shown in the second picture.
After making this bounding geometry, I wanted to make the difference polygon from ...
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Difference of two polyline layers in QGIS
I have an original polyline layer and a modified one representing only a part of the original network. In an example case I cut 10 meters at start and end of each feature using Geometry by expression ...
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Why do a line and polygon still intersect after using st_difference() in R?
I have a line that intersects a polygon, and I would like to get only the portion of the line that does not intersect the polygon. Using sf::st_difference() does indeed trim the line, but the result ...
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Difference tool retains records of deleted point features (without geometry)
I was using the Difference tool in QGIS version 3.22 on a points layer with a polygon overlay. This failed. I read this problem is commonly reported in 3.22 and upgraded to 3.30.3, as advised.
Now, on ...
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Multiple subtraction raster in QGIS
For each year from 1951 to 2021 I have two rasters: one precipitation (P) and the other evapotranspiration (E).
I want to do P minus E for each year--so I would like one output of the subtraction (P-E)...
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How to create one raster layer from two raster layers in which priority is given to one of the raster layers' values (the smaller in extent)
I have two raster layers of elevation data. One, of a larger extent, - 'warped' - is to 25m definition. The other, of much smaller extent - '194555-1_25cm_DSM' - but within the bounds of the larger ...
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Remove parts of line that are not contained within multiline
PostgreSQL 14.6, Postgis 3.2
I have two tables, new_geom and original_geom
new_geom is a derivation of original_geom that merged some lines that touched and had the same properties. It worked fairly ...
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Calculating 2 or 4 new marginal bounding boxes from 2 overlapping bounding boxes in Leaflet?
The Scenario
I have a web map that calls for data whenever the map moves. It sends the bounds of the map and returns data within those bounds. Our data source just got way bigger, so I am trying to ...
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Mask polygon with raster layer
I have very large raster, whih is basically merge of smaller rassters :
I would like to create separate polygons for each "group" of pixels with values, to get something like this (sorry ...
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Masking two shapefiles with MultiLineString and MultiPolygon errors
I created a shapefile by converting a raster to a polygon using raster pixels to polygon tool and used this as a base layer to remove unwanted areas with difference tool. I added multiple shapefiles ...
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Comparing smoothing algorithms in R
I am comparing smoothing algorithms in R. More specifically, the raster.gaussian.smooth from the spatialEco package and the focal from the terra package. Visually, the results look similar but the ...
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Rasterio how to find same values in excel
I have two geographical tiff files, the difference is 20 years. There are some values in the pixels of these drawings. I need to find differences between the second file and the first one. I tried ...
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Creating a layer showing difference before/after flood (raster)
I ran a supervised classification on two satellite images - (i) before and (ii) after a flood. Now even before the floods, there were pre-existing water bodies which obviously don't count as flooded ...
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Difference function in QGIS is extremly slow
I execute the difference function in QGIS. I have used it many times before, and it worked well.
For the final task I like to delete lines with my nationwide buffers. It is a lot, but I have had in ...
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