Questions tagged [simplify]
A type of cartographic generalization in which the important characteristics of features are determined and unwanted detail is eliminated to retain clarity on a map whose scale has been reduced.
177 questions
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Simplify by removing overlapping lineparts in adjacent polygon features
I am looking for a way of simplifying my GeoJSON file by removing overlapping lineparts between adjacent polygons.
I have a GeoJSON file with polygons of cadastral parcels which, by definition, are ...
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Simplifying adjacent polygons with Python while maintaining shared borders [duplicate]
I want to simplify adjacent polygons (GADM zones level 1) with Python while maintaining shared borders.
The general problem is well explained at Simplifying Polygonal Coverages with JTS. The best ...
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Simplify/generalize Polygons and keep topology of different layers PostGIS/QGIS
I have some polygons of a country, states, districts, communities and I want to simplify the geometry.
I already simplified the geometry of each layer but afterwards of course it doesnt fit with the ...
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Geopandas simplify results in gaps between polygons
The goal is to simplify the geometries of a shapefile containing multipolygons. However, when I use Shapely's simplify in geopandas, the result contains gaps between the polygons. I was hoping that ...
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Simplify geometries but keep them contiguous [duplicate]
I have several detailed contiguous areas. I need to turn each one into KML, but when I do so, the end result is too large (in terms of memory). Using PostGIS I need to simplify these geometries but ...
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Simplifying adjacent polygons using PostGIS?
I encountered a problem simplifying set of polygons that are adjacent. If I simplify each polygon separately with the Douglas–Peucker algorithm (which is used by many open source tools), the resulting ...
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Simplify multipolygon in Google Earth Engine
I am working on Google Earth Engine and trying to simplify a multipolygon by first reducing its vertices and then removing unnecessary polygons that have fewer than 5 vertices.
var gaul = ee....
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Transform the detailed vector layer in screenshot 1 into the simpler layer of screenshot 2
I have created a "detailed" vector layer of buildings from OS's VectorMap District data, styled with deprivation data (much like screenshot 1).
I would like to create a simplified layer from ...
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Simplify polylines by eliminating short lines?
I have a river network, extracted from a DEM. Then I split it to shorter segments. The split adds some points (as shown in figure) too near to each other. I wonder how I should remove those small ...
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Simplify my vector data to display it more efficiently [closed]
I have >1Billions points data (in geoparquet but could gpck) that I have to display in QGIS in a scale that doesn't need such precision (=we will not see all the details). It takes age to load in ...
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QGIS Simplifying polygons with keeping points inside of them
I'm creating a processing where I do calculations on address points inside of counties.
I need to generalise county polygons in order to make my processing faster.
How do I make sure that address ...
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Simplifying Raster Contours using ArcMap
Does anybody know a way to simplify a number of contour polylines derived from a raster dataset?
I need to generate a map that shows contour polylines at relatively small scale. With the contour ...
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Simplifying polygon by inner angle in QGIS
I'm trying to simplify a polygon using the interior angle of a vertex as the "tolerance" instead of the distance between vertexes. For e.g. the polygon in the image below would lose one ...
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Simplifying Ways in OpenStreetMap Data
Is there a (current) best practice to simplify ways? I have found:
https://github.com/podolsir/osmosis-simplifyways
But besides not being alive, here (http://permalink.gmane.org/gmane.comp.gis....
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Seeking algorithm for polygon straightening
I have a polygon that looks like this:
I want to get a result that ideally looks like this:
The best that I can come up with is a polygon simplification using shapely in Python:
Which algorithm ...
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Generalizing (simplifying) polygon shapefile or feature class in ArcMap while preserving topology?
I came across Generalizing polygon file while maintaining topology in QGIS? which asks for a QGIS solution to my exact question. I'm trying to do this in ArcMap. I start with a polygon shapefile (...
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Remove Slivers/Gaps generated after TopologyPreserveSimplification?
I am trying to simplify my geometry using TopologySimplifier to simplify my shapefile , but after this I am getting so many sliver/gaps( even trying with different tolerance (.001 to .005). Below is ...
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Why simplify algorithm has no effect on input in QGIS?
I have a LineString layer that I need to reduce the number of vertices. For example, some straight lines have intermediate vertices that add no value and should be removed. A slight loss of accuracy, ...
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EPSG:3857 to 4326 - incorrect geometry
I need to get simplified boundaries of all countries with some buffer around them (20 km). I am using QGIS, I converted my country polygons vector layer from 4326 to 3857, set buffer, used simplify ...
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While using simplify feature slider does not appear using QGIS
Using QGIS both 1.8.0 and 1.7.4, the slider does not show up after selecting features and click "simplify feature" botton.
Is there any special setting needed to show the slider?
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Reducing coordinate decimal places in WKT using C#?
I have imported several shapefiles into a Microsoft SQL Server 2017 database
When I use the STAsText() function on geography objects I get the following WKT:
SELECT [Adm0GeoBoundaryID]
,[...
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Simplifying geometries (generalization)
What are the recommended ways of simplifying geometries? Keeping in mind projections, and simplifying state geometries, for example.
I've heard about converting to an 'equi-distant' projection that ...
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What are strategies to simplify a vectorized raster layer?
For a GIS web viewer I am building, I plan to use large sets of vector data on coral reefs (source: Allen Coral Atlas). When viewing the downloaded data, it seems that the original source was raster ...
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Invisible layers when splitting vectors after simplifying in QGIS
I am working with elevation curves and I want to group curves by elevation. I can do it with the Split Vector Layer tool (Vector, Data management Tools) and choose ELEV as a unique ID field.
However, ...
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Speed up intersection on large polygons with PyQGIS?
Is there a way to speed up my script? I am new to PyQGIS. I am using QGIS 3.16.
What I need: I have 50 polygons (up to 1.675.000 hectares, mean 420.000 ha; one shapefile per polygon) and for each of ...
- 65.4k
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Simplifying Line Network Preserving Topology
I have a Shapefile (consisting of European major roads) with about 250.000 Segments which I have to simplify for pgrouting. But I can't seem to find a way to do that properly.
This is what it looks ...
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How to simplify streets such that separate driving tracks are reduced?
Streets in Openstreetmap have more detail than I need. For instance, I do not need separate street tracks for each driving direction; instead I just want to show the general path of the street. ...
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Original polygon is completely contained by new after simplifying
Is there a polygon simplification method that can create a polygon, such that the original is completely contained by the new one?
The aim is to create the new polygon from as few points as possible ...
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Simplify multipolygon removing small gaps in PostGIS
Is there a way to simplify multipolygon by removing small gaps in PostGIS? Example:
Original:
Simplified:
It could also simplify the shape as ST_Simplify does but in addition it should remove small ...
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Simplify a shapefile/GeoJSON polygon without "uncovering" territory?
I've been using Mapshaper to simplify some very complex polygons (boundaries of countries). The goal is to create relatively simple polygons which can be used to determine whether a given lat/lon ...
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Seeking algorithm for Lossless Polygon Simplification
Is there a standard/recommended algorithm for simplifying a polygon without shrinking any of its original boundaries?
Right now I'm using TopologyPreservingSimplifer within JTS and running into ...
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Can't call PostGIS ST_Simplify
How can I call PostGIS's ST_Simplify function?
postgres=# SELECT ST_Simplify( geom, 0.1 ) FROM mains;
ERROR: function st_simplify(geography, numeric) does not exist
LINE 1: SELECT ST_Simplify( geom, ...
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Simplifying Water Areas in QGIS for Artwork
I am using QGIS to create geographic artwork with topo and water features.
I have downloaded the NHDWaterbody dataset from the USGS. Some of the wetlands are causing me real issues. For example, here ...
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Warnings() in functions sf package
I'm running the code below and I get several "warnings". I used the sf_use_s2(FALSE) function to work with plane coordinates following the old way of the 'sf' package but even so I keep ...
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Ovals are being automatically simplified when drawn using ArcGIS Pro
Sometimes when I am drawing ellipses in a polygon shapefile, they save correctly and then simplify themselves into angular shapes. I don't understand why this is happening or only happens sometimes, ...
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Simplifying polygon product of erase tool results due to small gaps in erase features
I am using ArcGIS Pro 2.9 erase tools to erase overlaying polygons as such:
with blue circles as input features and gray polygons as erase features.
And here are my result:
there are awkward lines ...
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Simplifying polygon by number of points in QGIS
I am aware you are able to simplify polygons in QGIS based on distance tolerance but my questions is, is there a way to simplify based on a set maximum number of desired points?
For example, if the ...
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Geometry simplification for large scale aggregations in GEE
When aggregating on a large scale in GEE, does geometry simplification matter?
For example, when aggregating climate data on 30 km/pixel (e.g. NEX-GDDP), does it make computational sense to change ...
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Why won't lines from GPX simplify/generalize/smooth?
I am working with GPX data. I imported them to ArcGIS by 'GPX to feature' and then I created lines from these points. I am trying to smooth (or simplify) the lines now, but the tools 'smooth line' and ...
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Simplifying multiple lines to create central axis?
I have a layer with railway lines, downloaded from OpenStreetMap. Every single track is represented separately, so at trainstations, you have several parallel lines, as well as sidelines that lead to ...
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QGIS Simplify tool resulting in missing features [closed]
I am a very new QGIS user, but have learned much from searching this site for tools that are appropriate for what I am doing. However, I have reached a roadblock that has stumped me the past several ...
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Wang's Bend Simplify in QGIS
I am looking for an alternative to ESRI's Simplify Polygons - Bend Simplify method (I only have a Basic License).
Is there an existing QGIS plugin which supports this specific polygon simplifying ...
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Simplifying polygon edge while preserving minimum area and width [closed]
I am working with river buffer areas. The area that you see in the first picture is a 100-meter buffer of a polyline (a polyline isn't visible but it is there).
I want to simplify the edge in a way, ...
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Holes after topology simplification
After applying the topology simplification mentioned in the answer
Remove Slivers/Gaps generated after TopologyPreserveSimplification?
It is retaining the topology but is removing the polygon. Below ...
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Lining up boundaries at corner of polygons
I have a polygon layer with the boundary of a lot of zones. The boundary of many of them skips at the intersection where multiple zones come together (shown as in the picture). I am trying to find out ...
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Polygon boundary not adjacent after simplification [duplicate]
I am simplifying set of polygons that are adjacent. I used topologypreserveSimplifier which simplify each polygon separately the issue is the resulting polygons are not adjacent anymore.
After ...
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Removing unnecessary vertices?
I have over sampled polygons that I need to simplify, without changing the shape. basically, I want to reduce the number of vertices, by eliminating the ones that are useless and have the polygons ...
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Removing sharp curves using ArcPy
I have been trying for some time to find a way to eliminate the exaggerated curves in a contour curve that I usually obtain from line 0. The idea is to obtain a polyline that is more or less faithful ...
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1
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ogr2ogr (or other) simplification of polygons with shared boundaries
I am trying to simplify a collection of 100,000 or so polygons containing nearly 4 million vertices. The data is stored in a 2GB shapefile so there is no explicit representation of the topology ...
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Meaning of Simplify's tolerance parameter
The standard parameters of Douglas-Peucker's simplify algorithm are geometry and tolerance (e.g ST_Simplify in PostGIS). What's the meaning of the tolerance parameter? I know that the bigger the value,...
