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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Checking for overlapping polygons in QGIS [closed]

Since updating QGIS from version 3.20.2 to 3.24.0 I no longer have the same Vector > Geometry Tools > Check Validity options. This used to allow me to specify how much (area) polygon slivers ...
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Assigning attribute of polygon outline to most similar polygon using QGIS

I work with QGIS. I have a map with lake outlines which is basically a mosaic of three different years (2014-2016). I also have a map with the lake outlines for each of those three years. I now want ...
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3 votes
1 answer
290 views

Calculating proportion of a polygon covered by each raster category using R?

I am using R. I have a polygon v that covers multiple raster cells in raster z. How could I calculate what proportion of the polygon is covered by each category in the raster? I read a solution on ...
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2 votes
1 answer
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Filling holes and gaps in shapefile using QGIS [duplicate]

I converted a RBG to a raster then created a vector based on the values I wanted. The file looks good but there are some 'gaps' between the polygons. I tried the delete holes function but it doesn't ...
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1 answer
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Changing selection color of features in QGIS 3.20

In QGIS 3.20.1 when I select a feature of any polygon it turns white unlike the older versions that were yellow. Is it possible to change this selection color using a simple way? Note: I do not have ...
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Get raster from WMS

I am downloading Sentinel-2 raster files from Creodias. Several processed polygons are located on two or three tiles at the same time. I can download all the tiles, make a gluing and cut out the ...
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1 answer
38 views

Straight segment tool not working when editing in ArcMap

The straight segment tool is not working. I kept pressing right click to make it work but nothing happens. I'm working on ArcMap 10.7 .
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3 votes
1 answer
62 views

Self-crossing/intersecting polygon in QGIS that tools identifies them as valid

I am using QGIS 3.14 long term version. I need to identify these polygons that are self-crossing. Here are the tools I have tried SAGA's "Polygon self-intersect"; check validity from ...
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0 votes
1 answer
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How to get a list of the empty areas between the filled ones? (+size in ha)

I am an absolute beginner in GIS software. My goal is to get a list (or something similar) of all the empty polygons/areas between the colored ones. It would be perfect if the size and location of the ...
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2 votes
1 answer
154 views

Moving a polygon to specific coordinates in QGIS

I have downloaded a polygon online that represents the border of a property that I would like to do further work with. The problem is that the polygon is in the incorrect place and is the incorrect ...
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How to define the polygon limits based on a number of coordinated points [duplicate]

I have generated lots of coordinated points (lat, long) and now I'm interested in creating the polygon of those points. The problem here is, how do I know the points that are the limits of the polygon,...
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1 answer
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Extract Points by Attribute for each Intersecting Polygon in ArcGIS Pro

I have a points shapefile and a polygon shapefile, each with millions of features. All points lie spatially within polygons so that there is one or more points within each polygon. The points have an ...
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1 vote
1 answer
186 views

Project a shapely geometry over a linestring

I'm looking for the most exact way to project a shapely polygon over a line. I assume that any projected point of the polygon is inside the linestring. My first idea is to densify the boundary of the ...
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0 votes
2 answers
28 views

coverage layer as water network [closed]

I have polyline featureclass as water network. I want to create polygon layer around these line to became coverage layer but I want that to be automated and isn't manual.
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4 votes
2 answers
203 views

Why is my ST_Union output disproportionately large?

I have two multi-polygon geometry tables (see the figures below) in my PostGIS database and I would like to create a union of these two tables. They are ~12mb and ~1mb in size. However, the union of ...
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QGIS. Combining points data on a map with attributes in polygons

I have a project where I'm trying to combine flood risk data to a list of postcode (/zipcode) data. The postcode data is a csv that contains each postcode's easting, northing, longitude, and latitude ...
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5 votes
1 answer
132 views

Obtain the footprint of a large raster in PostGIS

I need to get the footprint (not the extent) 10GB raster in PostGIS similar to this question (but it's a very old question without any proper answer). So far the best approach I have come up with is ...
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1 answer
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Reclassify Polygon Shapefile into different classes based on features

I'm using ArcMap 10.4 I have small problems with my map. I have 7 years of data and I want to classify my map for the different years in different classes. In other words, the year 2010 have different ...
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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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3 votes
2 answers
157 views

Removing overlapping polygons without merging any polygons in QGIS [closed]

My layer contains overlapping polygons, as seen with some transparency. What could I do to remove the overlapping parts (in dark on the screenshot) without merging any polygon in order to obtain the ...
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7 votes
4 answers
187 views

Identifying self-crossing/intersecting polygon in QGIS

I need to identify these polygons that are self-crossing. I tried to run SAGA's "Polygon self-intersect" tool but it didn't work. update: I tried to use check validity and other similar ...
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1 vote
1 answer
68 views

Find polygon corners using JTS [closed]

Assuming we have different JTS Polygon objects, visualized example A and B. How can we go on and find the corners/coordinates for each polygon (blue circles) using JTS? The polygons have multiple ...
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1 answer
181 views

Creating polygon around points using ArcGIS Pro

I'm trying to create a polygon that uses the outer points as the boundary (in layman's terms: connect the dots of the outer points to have one polygon that represents the area). I've tried using '...
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1 vote
1 answer
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Creating point fill that exceeds polygon boundary in QGIS

My question starts off here: Creating random point polygon fill symbology in QGIS? In addition to the random point pattern fill of a polygon, I want my points not to be clipped by the polygon boundary....
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Subdividing very complex and big road polygon data into almost equal sized pieces while also dividing vertically depending on the width

This is a follow up question to the previous one I asked here. The solution explained there works pretty well for a small portion of the dataset I've got where there is no roundabouts or holes in ...
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6 votes
2 answers
147 views

Counting number of distinct areas in cell using QGIS

On the figure below, I have: a shapefile of cells of 0.5x0.5 degrees around the African continent a shapefile of different regions in Africa I would like to count the number of separate regions ...
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0 answers
31 views

Spreading out/pulling apart overlapping polygons in QGIS [closed]

There has been a lot of questions and answers on clipping/removing overlapping polygons in QGIS. However, my question is a bit different. Say, I have a mess of many polygons overlapping one another on ...
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1 vote
1 answer
93 views

Split seamless polygon representing river banks into separate polygons using center lines

I have a polygon that represents river banks. This polygon is seamless for all rivers. And I also have lines of each river. Here is the example of one situation: Is there a way to split the seamless ...
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6 votes
3 answers
471 views

Import unknown text polygon format to QGIS

I'm trying to visualize this park in the DRC. Thinking it was a WKT polygon, I isolated one shape as a test and saved it as a CSV. Here {"attributes":{"OBJECTID":27,"NOM":...
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35 views

Sub-dividing oriented polygon grid

I have a grid of squares which are not aligned N-S, E-W. These are 5m squares, but I've been asked to reduce these to 1m squares. Therefore I need to sub-divide one square into 25 squares on the same ...
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72 views

Polygons not showing outlines in ArcGIS Pro?

I work in ArcGIS Pro 2.9.1. I imported a project (.mxd) from ArcMap 10.8.1. There are two map frames in a layout view. One is placed onto another. There are polygons in the second map frame that I am ...
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1 answer
138 views

How to subdivide road polygons into equal distance polygons while also vertically splitting depending on the width of the road

I'm using QGIS and trying to divide a road polygons layer into smaller polygons, all having the more or less the same length as in the image below I roughly drew. Also, if the road width is above a ...
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3 votes
1 answer
158 views

Creating centre line of odd shaped polygon in QGIS

I'm trying to calculate a center line of an odd shaped polygon. When I've used the Polygon Tool 'Centerlines' with the setting 'All' is doesn't create center lines for all of the polygon, only part of ...
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1 vote
0 answers
44 views

Calculating area of polygon with consideration of slope in QGIS [duplicate]

I would like to know if there is an easy/efficient way in which you can calculate the area of a polygon considering the irregular slope underneath the polygon. I would like to know a solution in QGIS.
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1 vote
2 answers
38 views

Rule-Based layers not displaying in the correct order

I am having trouble with bottom layers overlapping upper ones within a rule-based layer. (screen showing the issue) It used to work just fine, I was able to create new polygons under ones previously ...
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-3 votes
1 answer
180 views

Get Xmin,Xmax,Ymin,Ymax from polygon in Python [closed]

I have a polygon. I want a CSV file that contains the xmin, xmax, ymin,ymax extent from the polygon in Python. What are the ways I can do it?
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2 votes
1 answer
50 views

Rendering NULL values with joined CSV file in QGIS

I have a set of polygons in a single shapefile layer. I have added a data table as a new layer and joined the two layers. Some of my polygons do not have entries in the data layer and consequently, ...
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0 answers
44 views

How to do st_intersection in PostGIS using R

I have a large polygon file in the form of .gdb (mygdb, ~10gb) and I need to crop it using another polygon shapefile (myshp, ~10mb). I want to do this PostGIS database using R so that it will be ...
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  • 405
4 votes
1 answer
69 views

Listing name of overlapping polygon in QGIS

In QGIS, I would like to assign polygons in one layer (ZIP codes) to polygons in another layer (counties). Specifically, I would like to know, for each ZIP code, in which county it is located. In case ...
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0 votes
0 answers
293 views

Plotting polygons in Python using GeoPandas and quantile scheme

I have a data frame with latitude, longitude and annual consumption data. I am trying to plot the annual consumption data using GeoPandas with a quantile scheme by making a polygon column. I followed ...
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2 votes
0 answers
46 views

Boundary Placement in QGIS 3.x

in ArcMap there is a great function for polygon labels - boundary placement. So at the boundary with a new polygon the labels of both polygons are displayed opposite each other. Is it possible to do ...
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0 votes
3 answers
53 views

How to merge features while keeping the originals

I have a polygon layer of basins and want to merge some of the basins, but still keep the sub-basins that form the larger basin. Is that possible without first duplicating the sub-basins?
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0 votes
0 answers
21 views

Removing overlapping polygons common to multiple layers in QGIS [duplicate]

I have 2 different layers of tax parcels, but there is an overlapping parcel common to both which I would like to eliminate. See the screenshot below of this overlapping parcel: This is a simple ...
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  • 375
0 votes
2 answers
67 views

Basemap transparency depending on polygon

I want to display a basemap outside a polygon with 50% transparency and inside a polygon with 0% transparency. Does anyone have an idea how I can achieve this? I use ArcGIS Pro 2.9.1
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1 vote
1 answer
132 views

Remove polygons that touches other polygon border in GeoPandas

How to remove polygons which touches other polygon border? I have a polygon and a single box outline. I need to get polygons which are outside the box and do not touches box borders and polygons which ...
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2 votes
4 answers
207 views

Counting points in polygon by time in QGIS

I want to count the points in the polygon by time category. However, the point have time category. When I want to use "Vector/AnalysisTools/Count points in polygon" option, it does not ...
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7 votes
2 answers
372 views

Creating square polygons of given length from single corner point in QGIS

I have 30 points, each one represents the SE corner of a 1.5 by 1.5m plot. I want to create polygons to represent these plots. How do I create square polygons from a corner point and with a specific ...
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0 votes
0 answers
87 views

Point projection on a polygon along each axis

There is a method in this thread that allows defining a concave outline around a 2D set of points. import alphashape import matplotlib.pyplot as plt from descartes import PolygonPatch points = [(17, ...
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0 votes
0 answers
29 views

Getting the index MSAVI2 with Landsat 7 images

I am new to the Google Earth Engine script world. I need to obtain the MSAVI2 index on a particular polygon, but it throws me an error in the line: .map(maskClouds), which throws: maskClouds is not ...
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1 vote
1 answer
70 views

Comparing polygons in two layers based on their location in QGIS

I'm trying to compare two layers representing the cycleways of my hometown. I've exported one layer from OpenStreetMap and the other from a regional web site. Now I want to compare the two layer and ...
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