Questions tagged [polygon]

On a map, a closed shape defined by a connected sequence of x,y coordinate pairs, where the first and last coordinate pair are the same and all other pairs are unique.

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Accessing watershed boundary for lakes in R

I have had success accessing unique database IDs and polygons for various lakes in the US. I'm now looking to get polygons for the watersheds associated with these lakes, but have stumbled a bit. ...
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What is the best way to display a large shapefile (with polygons) as a layer on a leaflet map?

I have a leaflet map of the UK with around ~2000 points total points and a bit of metadata loading for each point with two side-panels showing the metadata. These points are drawn from several tables ...
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6 votes
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425 views

Finding distance from points to the boundary of the nearest polygon in Python

I asked this question on stackoverflow.com but it seems that doing so here is a better option. Context: I want to compute the distance from points to the closest boundary of the closest polygon to ...
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Randomized organic warp of adjacent polygons that preserves topology and fixed nodes

I'm looking for algoritms to modify a set of polygons to make them appear more organic. They still need to maintain their topology and furthermore some of the nodes might be fixed. Please see the ...
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Creating Raster that sums up input polygons using QGIS?

I am using QGIS and I have a shapefile with buildings. From these buildings, I have made a Buffer with variegating radius. The Buffer also have data about the demand for Parking spots for each ...
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Creating text buffer in legend QGIS 2.18?

I work with this polygon layer and this is my map composer: I used the labels with Text Buffer (yellow and red), and I try to find how I can make the same text buffer in the layer name in the legend. ...
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Clip of polygons does not work properly by invalid geometry

I want to clip a polygon shapefile by another polygon shapefile. Input polygon is the green one (first), clip polygon is the light blue one (second) and the result should look like the dark blue one (...
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5 votes
1 answer
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Counting stacked polygons in PostGIS

In my data set I have cases where I have multiple polygons stacked upon top of each other. I assume that those polygons have equal geometries but since there are a lot of them I am not sure 100%. Data ...
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Close gaps between some polygons, which are adjacent in reality

I have tens of thousands of polygons (farmer plots) which have been measured while on the fields. This has caused plenty of gaps between some polygons, which is not the reality. I would need to close ...
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  • 135
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Clip completely overlapping polygon(s)

The shapefile that I'm working with (in QGIS) has over more than 250k polygons. But unfortunately a lot of the polygons are overlapping. The focus of my challenge is to delete or clip the polygon ...
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535 views

QGIS Zonal Statistics for polygons is missing results?

I am carrying out an analysis using QGIS 2.14.1 where I am dealing with point data that have been randomly displaced by either up to 2 Km or 5 Km. I have generated a buffer of the appropriate radius ...
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Sorting points to create polygon in PyQGIS

I have list of points and I want to create a polygon. First I need to sort points for that I tried: Find the center point of all points Calculated angle from the center to each point, Based on angle ...
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4 votes
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Select subset that is spatially equally distributed

Let's say I have a table point with ~10.000 rows. Each row contains a POINT(x, y). I also have a table polygon with POLYGONS(...). The points in the point table are unequally distributed in space. ...
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377 views

Plot polygon on rasterio window

I'm trying to plot several polygons on a raster. Several posts suggest to use matplotlib and descartes like this one: Plot shapefile on top of raster using plot and imshow from matplotlib My polygons ...
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280 views

Reshaping polygons while preserving area

I'm looking to manually skew the shapes of areal polygons, but need to ensure their areas are not altered. Is anyone aware of any GIS tools or programming workflows that exist for manually reshaping ...
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3 votes
1 answer
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Split polygon by regard of distance to other shapefile

Is there some function that use distance to point/polyline layer to split a polygon layer In Sweden the law says that undivided water belongs to the nearest property so sometimes I need to calculate ...
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3 votes
2 answers
92 views

Dissolving isochrones from point layer in QGIS

I have created a set of isochrones (3, 5, 10 minute walk times) from a point layer. I now want to dissolve the layer to make it more readable. However when I try to dissolve based on the field that ...
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Using OSMOSIS to extract multipolygon data from .pbf file

To update my database I need to extract some data from the OSM database. To do it I have downloaded the osm *.pbf file from the website of GEOFABRIK. From this PBF file I wish to extract all the ...
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3 votes
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Adding attribute of polygon orientation depending on neighbors in QGIS

I have a shapefile with buildings as polygons. Is it possible to add attribute columns referring if the polygon boundary is "other polygon" or "outdoors" for a certain orientation (...
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3 votes
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412 views

Why GeoPandas clip is so long

I have an issue with geopandas.clip that I think it's so slow. In input I have a rectangular polygon (bounding box more or less around alaska) in a geodataframes and 3 other geodataframe with ...
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3 votes
2 answers
470 views

Cutting out polygon by GDAL in Python

I use the rasterio to cutting out polygons from TIFFs. The problem is rasterio is too slow. I am looking for something another and I would like to use GDAL but I don't know how to write the code. By ...
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3 votes
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213 views

Smart way of finding the polygon intersection of a huge GeoJSON file with a small GeoJSON file without looping through all polygons

I have a huge GeoJSON file (over 300MB) which has multiple different polygons. Also, I have a very small GeoJSON file with only one polygon that doesn't have more than ten points. Using the ...
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3 votes
2 answers
830 views

Calculating the area of multiple polygons using GeoPandas

I am writing a Python script to calculate the area of polygons, as I have a small polygon, I am getting the area of polygon 0.000. A shapefile contains multiple shapefiles. I am thinking due to the ...
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3 votes
2 answers
176 views

Extracting lines from polygons/buildings based on adjacency to lines/streets

I have a building and street shapefile of a district. I am looking for a way to select and eventually extract those lines or edges of the buildings that face the street. however the extracted edges ...
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3 votes
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Geometry checker not removing overlap between features

I have a polygon shapefile layer (CRS EPSG:27700 British National Grid) that has a deliberate overlap and gap between features. When using the Geometry Checker Plugin (V0.1) in QGIS 3.10.9 I am ...
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3 votes
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80 views

How to split a polygon in 9 equal parts but I want to use different orientation on QGis?

I want to split a polygon of a terrain that I generated through coordinates on QGis. But at the same time, I want to do perform such an activity by testing different orientations for the terrains ...
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3 votes
0 answers
54 views

Dividing polygon into tiny polygons of particular size

I would like to divide/cut an irregular polygon into tiny polygons of a particular size(1.6m x 1m) in such a way that most of the irregular polygon area has to be utilized (an OPTIMIZATION MODEL) The ...
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3 votes
0 answers
63 views

Least number of polygons to cover vector in QGIS

I have two layers : Polygon rectangles layer representing different footprints Line layer representing roads I want to know what is the least number of polygons from the polygon layer do I need to ...
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3 votes
0 answers
127 views

Polygon Divider QGIS Plugin creates less equal parts (polygons) than asked

I've installed QGIS 3.16 for Windows. I digitised a polygon layer (limits of a city) and used the Polygon divider plugin to divide it in 10 equal parts (polygons). However, as a result, it created ...
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3 votes
0 answers
61 views

Symbolize thousands of polygons to identify similar geometries

I would like to categorize polygons with a similar enough geometry so such similarities can identified at a city-wide scale. I'm trying to identify if street layout is a useful spatial characteristic ...
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3 votes
1 answer
248 views

Fill in areas between lines with polygons?

I have to make a geographical map. I have to fill in the gaps between the lines with polygons. Is there a possibility to just trace those lines automatically? I have to do everything manually now, ...
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3 votes
0 answers
56 views

Cut one polygon into smaller polygon with other polygons

I want to use one layer with numerous polygons in it (layer 2 in attached image) to cut a big polygon on another layer (layer 1 in image), so that said big polygon is separated into smaller polygons. ...
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3 votes
0 answers
57 views

Joining attributes from points to polygon

I am working with two shapefile, polygons and points. These shapefiles do not overlap and have different attribute values. The point layer contains data that I want to join to the beginning and end ...
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3 votes
2 answers
907 views

ArcGIS Pro: Create polygons from outlines of unclosed lines

First a disclaimer: I have very little experience with ArcGIS, I usually use QGIS and only recently started using ArcGIS Pro. I have a River dataset from the Natural Earth Site, then made its ...
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3 votes
1 answer
891 views

Problem with dissolving polygon layer with many features in QGIS 3.4.1

I am currently working on a set of data that defines restricted areas for use of photovoltaic modules. This set of data amounts to 270.00 polygons in total (with their own geometry). For simpler ...
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3 votes
0 answers
253 views

Generalizing / simplifying multipolygon in PostGIS without missing polygons?

By following the rules from this site, I got the output but some polygons do not come within the simplified polygon. I think the problem is with topology. Is there any solution?
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3 votes
0 answers
250 views

Creating equidistant sampling points in polygon in QGIS 3.6.0?

I have figured out how to add random points inside polygon boundaries. Although this works well, nevertheless I need a few different things to happen for my application. What I would like to do is ...
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3 votes
0 answers
387 views

Unable to compute intersection between two polygons using PyQGIS?

I have two polygons in different layers. I am trying to find the intersect between the two polygons. Below a figure showing my test case. I initially wanted to find the intersect between the green ...
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3 votes
2 answers
2k views

QGIS "Sum Line Lengths" return 'nan.'

I have a polygon shapefile and a (merged) line shapefile (both are zipped). When I use Vector -> Analysis Tools -> Sum Line Lengths on these shapefiles, I get a layer with some of the LENGTHS filled ...
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3 votes
1 answer
1k views

Draw polygon on load not working - OpenLayers

The following code should have 3 features: Draw a polygon on load On draw end send coordinates On modify end send coordinates 2&3 work as expected. I added the drawn polygon last, there is no ...
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3 votes
0 answers
159 views

Converting polyline to polygon without 'Feature to Polygon'

I am attempting to create a script tool to automate some processes at work. Part of this process was to manually cut (using Cut under Editor) a buffer. My approach to this has been to try and split ...
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3 votes
0 answers
75 views

Dynamic filtering based on selected Layer in ArcGIS Desktop?

I am not sure this is even possible, I have about 38 geographical polygon layers showing areas of the UK, I also have a query (point layer) that shows all of the offices around the uk. What I am ...
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3 votes
0 answers
165 views

Why do I get invalid elements (polygons), when smoothing a vector layer (smooth geometry)?

The problem occurs, when using the commands "Smooth geometry" or "v.generalize.smooth" in QGIS. The shapefile, which I want to smooth, shows a flood water level and looks like this: The water level ...
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3 votes
0 answers
1k views

Increasing size and changing color in centroids, lines, and polygons

In the QGIS python console, I am able to get the active layer with layer = iface.activeLayer() but I need to be able to change the size and color of both centroids and polygons. For a polygon layer, ...
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3 votes
0 answers
844 views

Near Tool in QGIS

I am looking for an equivalent to the Near- Tool from ArcMap in QGIS. I have a Polygon Layer with potential areas for a new school and need to calculate the distance (in meters) to a point layer (with ...
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3 votes
0 answers
230 views

Fill in spaces between polygon features, voronoi style

I'm looking for a way to merge polygons across the empty space between them with a Voronoi-type result. There is a very similar question here, but the approaches outlined in the comments did not ...
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3 votes
0 answers
116 views

Constructing contiguous regions with similar properties by graph partitioning

I have census data for census output areas. Each area is a geographical region. I would like to partition these areas into contiguous super-regions with similar properties. For example, in each area ...
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  • 131
3 votes
0 answers
77 views

QGIS - Layer missing polygons after pointsfile transformation

I'm using pointsfile transformation in QGIS for the georeferentiation of my layers. After the transformation the result some times has polygons missing like here: Why is this happening? How do I ...
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3 votes
0 answers
465 views

What does "Feature doesn't have a geometry" mean in QGIS?

When I open the .shp file and click on specfic item in the attribute table, in the canvas, it said "Feature doesn't have a geometry". Is it the same as "geometry is not valid", or does it simply mean ...
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3 votes
0 answers
4k views

Clipping a raster by a polygon layer: Error "Cutline is not valid after transformation"

I have a raster layer (3 cm x 3 cm) and a vector layer with polygons and when I try to clip the raster by the polygon layer to have just the bare earth/ground regions left over, so I can interpolate ...
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