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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Removing black lines in between shapes in QGIS

In QGIS 3.22.7 I have a large dataset consisting of small square geometries (for reproducibility, a sample of this data can be downloaded from here; the total file size is 9 KB for all of them). When ...
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Distance between polygons and points in geopandas

I have a main polygon of ploygons that have areas mapped out on a map and a bunch of points such as sample below NAME lt ln 1 12.9336806 77.6122669 2 12.974768 77.767745 ...
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QGIS 3.22.8 Raster sampling with polygons

This is a DEM of a slope. I have made a polygon grid 10X10. I can't find a command to sample the raster by polygons. I've thought something similar with r.neighbours picking the minimum value of the ...
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Looking for QGIS equivalent of ArcGIS tool for buffering without polygons overlapping regions of neighboring boundaries

Is there a way to create buffers around a group of polygons (vector file) in QGIS where the overlapping buffer parts are not in the result? Please see picture example: I've seen a question asked ...
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Bringing in another layer in the Geometry Expression coding

Im looking to create a output triangle using the Geometry by expression tool. I have two layers, layer 1 is a viewpoint and central location and layer two is a collection of locations. I want make a ...
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There's any way to export data from Access to polygons without having UniqueIDs?

I have polygons. I would need to have more information on them. I have that information in an Access database. But I don't have any identifier to serve as a reference. When I do a CSV import, it doesn'...
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Multiple hatched fills in polygon layer (ArcGIS Pro)

The problem I am facing is, that the "historical" map has different pipes in terms of orientation as well as separation and I need to digitize them: The historical map contains several pipe ...
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Exporting data from points to a polygon

I'm new on GIS. We were migrating from an old map program to QGIS. My problem is that I need to have Polygons with data. And I have the information that I need in the polygons in "entities" ...
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Split polylines at each polygon boundaries in QGIS [duplicate]

How to split polylines at each polygon boundary in QGIS ?
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Leaflet js add polygon with offset around another polygon

I am pretty new in working with Leaflet js and I have a polygon var coords = layer.getLatLngs(); L.polygon(coords, { fillColor: 'red', fillOpacity: 0.5, weight: 20, color: 'red', opacity: 0.5, fill: ...
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Same symbology and color for all attributes of layer in QGIS

In QGIS 3.22.0 (Bialowieza) I have a polygon layer with different attributes. I'm making a categorized map for each attribute in my table. For that I'm duplicating and renaming my layer corresponding ...
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Map View in R: Labelling Name for Polygon in Map

I have created following choropleth map for cropland. The code I used is:- library(mapview) library(dplyr) library(sf) setwd("C:/Users/lenovo/Desktop/IEM") Province3Miscellaneous<-...
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Forcing ArcMap to label polygons features always straight at any scale [closed]

I want to label polygons features always straight, but when I try to change the scale or zoom out the label placement changes to be horizontal. How can I keep the label placement to be straight always?...
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Methods for edge matching polygons to be used in ArcPy [closed]

I am looking into methods for harmonizing polygon boundaries for a set of subregion data with the end goal of writing a script to handle the processes automatically. So far, I have gone down the route ...
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Subtracting area of a specific set of raster values from polygon area using QGIS

I am currently working with parcel data and a raster slope analysis in % change I created with DEM data. I symbolized the slope analysis discrete 0-2.5%, 2.5-5%, 5-7%, 7-12%, 12+% and overlayed it ...
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Dividing a square into smaller squares by using their shapes rather than their bounding boxes in R

I want to divide a square into 25 smaller squares. The square layer has a UTM coordinate system, so when plotted, it doesn't have flat bottoms and tops. When I try st_make_grid() function to overlay a ...
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Merging adjacent polygons with aggregated sum beeing inside a certain range

The data I have a polygon layer with polygons (download the data here) of different sizes as can be seen on the screenshot. Each polygon contains a value for the attribute called count. The range of ...
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Raster values ​changed after clipping with polygon [closed]

The procedure went well. Image 1 represents the raster (Chelsa) of annual mean temperature (bio1). I clipped it using a shapefile of country boundaries and the resulting image is image 2. As you can ...
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Generate images from map [closed]

I'm quite new to QGIS and I want to generate set of images from the map and layer which I have. So I have XYZ tiles map (NYC.gov tiles orthophotography) and Polygon layer. I want to transfer ...
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Counting total number of points within polygon (Buffer) layer using ArcGIS Pro

I'm trying to count the total number of points contained within a polygon layer. I have a series of buffer layers, each getting progressively larger and encompassing more points. I have used the "...
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Clipping a raster converted to a polygon with a polygon [closed]

I have a task to figure out how many agricultural areas are located in a defined altitude. The agricultural areas were a polygon, while the altitude/DMNV was a raster. I converted it to a polygon and ...
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2 answers
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Creating graduated classes for election swing map in QGIS

I am using QGIS right now to create an election swing map. This is different from a usual election map in that it measures differences in winning margins from one election to another. For example, Joe ...
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Polygon cordinates to array

I have an array of Polygons where each object looks like this {'type': 'Polygon', 'coordinates': (((-98.03706782884247, 44.72279408402323), (-98.03706782884247, 44.71524098343729), (-98.02951472825653,...
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Clipping features in a polygon from another feature in the same layer

I have a polygon layer with a number of features which overlap (in my case this wildfires in an area over time). I would like to clip the underlying features so there is no overlap. To elaborate I ...
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How to modify the coordinates of polygon by GDAL?

I'm used the GDAL to modify the coordinates of polygons. I have referenced the C++ and Python versions of the code and modified them in Java: String ShpPath="G:\\GeoData\\New_Shapefile.shp&...
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1 answer
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Generate random polygons within another polygon using shapely in python

I have a use case where given a polygon on the US map, I need to generate n rectangles within the polygon defined on the US map. I have been trying stuff with shapely, but stuck. So the code would ...
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How to identify narrow/cutbacks/spike for lots of polygon

I'm working on vector data and want to detect/identify a polygon called narrow/spike like the attached image. Is it possible to use open source software? It can't be done using integrated in ArcGIS.
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2 votes
1 answer
34 views

Iterating over each pair of coordinates in Multipart geometry using Shapely

This question is related to Access each (x, y) within Multipart gdf.geometry.interiors. With a MultiPart geometry.interiors: from shapely.geometry import Polygon exterior = [(2, 8), (7, 8), (7, 3), (...
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6 votes
1 answer
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Representing difference between polygons only with Symbology in QGIS

In QGIS 3.22 I am trying to visually represent a difference between polygons after its change. In the end I want to know where the polygon was enlarged (#72ff85) and where it was degraded (#ff7272). ...
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QGIS 3.24 - how to export points as arc or polygon

I have a GPS coordinate file that defines points (locations.) I have a second application that is limited in that it can only show arc or polygon shapefiles. This application can't process a point ...
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4 votes
2 answers
299 views

Why do single-part WKT polygon vertices require double parentheses?

Regarding the WKT standard: Wikipedia: Well-known text representation of geometry Why do single-part polygon vertices require double parentheses? That seems inconsistent with single-part points and ...
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5 votes
2 answers
121 views

Flipping polygon around arbitrary axis in QGIS

I want to flip a vector polygon about an arbitrary axis. What I would like to do is select the polygon to flip, pick two points (A & B in image below) identifying the axis about which the flip ...
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Error of polygon

How to find errors in polygons, such as likely gaps but not, but can't use the topology tool at ArcGIS, because the error results are not the error I want to find. So one polygon should overlap with ...
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1 vote
0 answers
50 views

Merging vector tile polygons for perimeter labelling in QGIS

I'm working on recreating a base map style inspired from Mapbox Outdoors in QGIS. For this, I am using the Mapbox Terrain vector tileset as a Vector Tileset in QGIS. I can style features and add some ...
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1 answer
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gBuffer filling polygon holes

I am working on a large polygon containing multiple polygons, which requires me to set a buffer in order to perform other analyses. I used R to do the buffer, for example, a -> gBuffer(b, byid = T, ...
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MySQL - Filter a table based based on location / distance - ST_Distance

I have table with Polygon geometries. I'd like to filter the table to include rows that are at a certain distance from a Point coordinate. Here's a fiddle link for table schema, data etc. https://...
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3 votes
1 answer
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Highlight polygons using comma delimited text coordinates QGIS

I am new to GIS. I have significant CAD experience and some limited Python knowledge, and am generally familiar with basic QGIS functions. In short, I will have several CSV files containing co-...
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2 votes
2 answers
110 views

Expression for extracting specific parts/geometries from dataset in QGIS

Solution below worked for a small subset with a filesize <<1 gb, for larger file sizes another solution would be needed I'm trying to formulate an expression which extracts specific parts/...
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1 vote
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Spatial clustering with areas in QGIS or Python

I am working in QGIS with shapefiles containing several polygon features with various areas. I would like to cluster neighbor polygons in a way that results in clusters of approximately the same total ...
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1 answer
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Invalid GIS data provided to function st_polygonfromtext in MySQL

I have a table in MySQL with geometry data in one of the columns. The datatype is text and I need to save it as Polygon. I have tried a few solutions, but keep running into the error Invalid GIS data ...
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  • 345
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1 answer
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Creating polygon mask in QGIS

In QGIS 3.22.5, is there possible to use polygons for the masking layer? I want to use numerous little polygons to mask lines (only layer which consists of lines). In ArcGIS that works just by ...
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3 votes
2 answers
150 views

Selecting the maximum value from series of polygons that intersect with line in QGIS

Is there a way to select the cell (single) with the maximum value in a polygon layer using the intersection of a line? The first image is the grid (polygon) layer with the attribute field "VALUE&...
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  • 105
2 votes
1 answer
56 views

Polygon boundary from shapefiles not in latitude/longitude format

I just downloaded the shapefiles for the County boundaries in Minnesota from here. Now I am expecting the boundaries of the Polygons/MultiPolygons to consist of latitude and longitudes (according to ...
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2 votes
1 answer
40 views

Calculating cumulative sum of area values in attribute table by graphics in QGIS

In QGIS I have a set of polygons divided into plots, each polygon has a diameter and area. I would like to sum up the polygons per each plot area. From the attribute table, the polygons are not ...
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3 votes
2 answers
86 views

Finding nearest polygon in PyQGIS using QgsSpatialIndex

I am trying to write a custom processing tool for QGIS which joins the nearest attributes with some conditions. Therefore I'd like to use a QgsSpatialIndex to increase performance. This works ...
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1 vote
0 answers
28 views

Remove the longest segments of a polygon using QGIS

Is there an expression or tool that allows the user to remove the longest segments of a polygon? The end result would be two end segments (lines)
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0 answers
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How to make polygon shapefile from .csv file with ShapeSTArea and ShapeSTLength features?

I have a .csv file that includes x and y coordinates as well as ShapeSTArea and ShapeSTLength features. (see below) I'm hoping to turn this .csv file into a shapefile that instead of displaying ...
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1 answer
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Enlarging gBuffer width changes polygon shape

I am having some issues with spTransform and the gBuffer function. I basically have a polygon that I want to buffer with gBuffer (not with st_buffer for other reasons). For some reason the shapefiles ...
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  • 9
2 votes
1 answer
32 views

Splitting feature into individual features in QGIS

In QGIS I have a layer that is made up of a large number of polygons that are merged together to form one feature. Is it possible to split this feature into the individual polygons that make it up so ...
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1 vote
0 answers
23 views

Selecting smaller polygons first into a QGIS Web map

Here is my issue, I am having a QGIS Map with polygons, I edited the symbology in order to stack the smaller area ones first so they can be clicked first to open the pop up window in the web map later....
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