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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13 views

Extract Latitude/Longitude from polygon vertices on QGIS

Created a global map by adding the OpenStreetMap and WorldMap layers in QGIS. Drew polygons over that, creating what I believe is a polygon layer. I've also created a layer of the Nodes/Vertices of ...
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Contour Polygons to 3D

I am trying to make a 3D representation of the map below. I have 3 polygons which represent contour lines. It starts at 0ft for the outside polygon, 10ft in the middle and 20ft for the very center ...
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Regroup multiple polygon with same attributes in one

After looking for an answer on some forums (without success :/) i post here in hope on of you can help me. I have a polygon shapefile with thousands of entities (=row) and >10 attribute column. A ...
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1answer
29 views

Find the side of a polygon pointed by an azimuth

I have a dataset of points (longitude, latitude) and I used QGIS get a Voronoi diagram of these points. Each point has an azimuth and a wedge width that I also managed to visualize in QGIS. As you ...
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Generate concentric polygons using Turf

I'm interested in trying to reproduce this kind of cartography in a Mapbox/Turf/vector tile stack: I would start with the polygon for the lake edge, and generate a series of concentric polygons ...
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1answer
21 views

Finding“NoData” area/percentage using ArcGIS Desktop?

I have a RGB raster that has been processed to remove cloud/shadow coverage and then put in a mosaic with other RGB rasters to fill in the missing gaps. Unfortunately all the gaps have not been ...
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Is there any reason why I shouldn't create a polygon using ESPG:4326 - WGS 84 in a project which is set to EPSG:3857 - WGS 84 / Pseudo-Mercator? [on hold]

The project is set to Web mercator (EPSG:3857 - WGS 84 / Pseudo-Mercator) because it uses a google basemap through quickmapservices. In the future, I plan to use the shapefiles on top of another ...
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1answer
41 views

Polygons out of a shapefile in QGIS

I have added a layer with tracks and track points from OSM in QQGIS and exported this GPX file into an shapefile. Now I wanted to calculated the area of the buildings. I tried to do this with the ...
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1answer
28 views

Updating z value of geometry using updateCursor?

I am trying to update the Z value of a polygon using update Cursor and it just doesn't work! I have been exploring this site and trying different codes without success. I have a shapefile with ...
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Converting a raster pixel by pixel to vector cells in Python

Problem Today I needed to convert raster to a shapefile with rectangular polygons representing each pixel of the raster in Python, including the pixels with value 0. Related questions: Converting ...
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3answers
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Concatenating list of strings using ArcPy?

My code from Returning strings showing all vertices from all polygons in shapefile using ArcPy? creates is the following: import arcpy fc=r'D:\GIS Data\TOOLS\EV calc in Python\Data.gdb\PolyWGS842' ...
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1answer
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Unremovable objects/lines QGIS 3.x

How can I remove "red lines" that become permanent to my map canvas while trying to digitize different shapes. The program just leaves the outline of what I'm trying to draw. It still remains even if ...
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max elev value from raster [closed]

data: raster (srtm) polygons a. (1 degree grid) polygons b. buffer from polygon a. (1 degree grid with outer buffer 8 km.they overlapped) HOW to take: max elevation in every polygon a. max ...
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Removing empty polygon from sf object in R?

I have such object: > p_mb Simple feature collection with 52 features and 0 fields (with 9 geometries empty) geometry type: GEOMETRY dimension: XY bbox: xmin: 585001.4 ymin: 211001....
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1answer
32 views

Remove polygons having less than 4 coordinates in R

I have a multiPolygon shapefile of buildings in a particular city. I read it in with readOGR and and transform it to my desired planar projection with the following code: buildings_data<-readOGR("...
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1answer
18 views

Split polygons by area/percentage with QGIS 3.x

Is there a function in QGIS 3.6 Noosa that allows me to split polygons with given area or percentage? There is a plugin for QGIS 2. "split polygons" that seems to have exactly what I'm looking for, ...
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2answers
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Deleting polygon defined area from multi band raster layer in ArcGIS Desktop?

This is a similar question to Deleting polygon defined area from raster layer in ArcGIS Desktop?, but I need the answer to be able to apply to multi bands since I am working with a RGB file. I have a ...
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How to correct border between 2 polygons in R? [duplicate]

What algorithm to use to correct (average) the borderline between 2 polygons? All I know is that they have their own borderlines very close to each other. Sometimes they may overlap, otherwise not. ...
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1answer
76 views

Returning strings showing all vertices from all polygons in shapefile using ArcPy?

I want to have a string showing all vertices from all polygons in a shapefile. In my example below my code lists all vertices and the first column shows the polygon they are part of (I only have 2 in ...
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Splitting a layer containing multiple polygons into multiple layers each containing one polygon [duplicate]

So firstly, I used the buffer tool in Qgis3 to create (twenty) polygons with a certain width from (twenty) points. This lead to the situation below, where o1 and o2 are two original points and 1 and 2 ...
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Polygon boundary is not properly connected in R

I have two points sets, when plotted using geom_point, they look like: What I want to do is draw a polygon using these two datasets, and I expect to get a ring-shape polygon. However, when I use ...
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QGIS: Polygonize error

Running the Polygonize tool in QGIS keeps generating the following error: Processing algorithm… Algorithm 'Polygonize (raster to vector)' starting… Input parameters: { 'BAND' : 1, '...
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2answers
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Adding information to polygons inside polygon from other polygon in QGIS?

I have two layers in QGIS. The first one contains buildings and the second one contains blocks. Now I want to add the ID of the block to all buildings inside this block. Are there any functions in ...
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1answer
28 views

Polygonize specific raster values QGIS

I have a raster of 36 classes of the land cover in South Africa. However, I only need 4 of these classes and create a polygon out of these 4 classes combined. I have now used the raster calculator to ...
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38 views

Adding Polygon to shapefile of particular area from Excel?

I have Excel data in which polygon number is given, in correspondence to that there is particular Area given. I have 5000 to these entries. Now in the shape file, we have to edit every polygon and add ...
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1answer
56 views

Making path between polygon using QGIS?

I am trying to draw a line (vector layer) of a certain length that that tries as much as possible to dodge the green polygons. Assuming a starting point, is there some sort of line centroid ...
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1answer
23 views

Rotating Polygon in 3D Space as KML for Google Earth?

I'm trying to create this effect in a KML to be displayed in Google Earth. I am writing in KML 2.1 as a reference. I know it is possible to create a polygon that is circular in appearance, but can ...
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Will Polygon Volume work if my polygon does not represent a constant plane height?

I am working on calculating flood inundation volume in ArcMap. I have polygon layers that represent flood inundation at specific recurrence intervals. My layers do not have a constant plane height ...
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1answer
39 views

Unclosed linestring to polygon works with QGIS but not with PostGIS

Just like the title, I am extracting OSM riverbank and a lot of riverbanks in OSM is in 'unclosed' linestring. This is the original river shape i extracted from OSM In order to polygonize the ...
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3answers
30 views

Merging different types (e.g., polygon with polyline) of shapefiles? [duplicate]

I want to create a watershed shapefile with areas, streams and pour points in it. Is there a way to merge the areas (polygons) with streams (polylines) and pourpoints (points)?
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ArcMap: interpolation for single polygons individually

The red polygons in the image represent the boundary of infills. The raster (colored area) within the polygons is interpolated from the point shape file (black dots). The image shows an example where ...
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Creating buffer for polygon in R

I am quite new to GIS area. I have a polygon and use concave hull function I could get a boundary like this What I what to do is add a certain-width band along the boundary, so that it could look ...
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27 views

Assign different colours to intersection between two polygons and difference area

I am quite new to GIS using R. I have two sets of data, upon which I could create two polygons like this: What I want to do is colour the common area (inner 'circle') and the space between borders. ...
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1answer
133 views

Finding overlapping polygons in two shapefiles and deleting them in R? [closed]

I have two shapefiles with more than 1000 polygons each, and they represent two types of agricultural fields in the same area, which means they should be different types. Some of the polygons are ...
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Creating additional attributes for regional intersections?

A certain country is (simultaneously and independently) divided into 400 regions and 100 judicial districts. Each division is represented by a separate multipolygon layers with units as features. ...
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1answer
79 views

Sampling random cells from certain areas of a cropped raster?

I have a raster cropped to the extent of some glaciers and divided it into three masks to address inner glacial cells, border cells and non-glacier cells adjacent to the glacier. Data can be found ...
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1answer
79 views

Removing polygon holes in OpenLayers

I wrote some code for removal of polygon holes whose area value is under the hardcoded threshold. source_g.getFeatures()[0].getGeometry().getPolygons().forEach(function(poly){ if(!(poly....
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1answer
63 views

Addressing just the outermost cells in a raster?

I have a DEM cropped to the extends of a shapefile with different glaciers (see here for data: https://drive.google.com/open?id=1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT). DEM <- raster("***Glacier_Clip1....
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Store the lat long coordinates in matplotlib figure to a table in Python

The matplotlib figure is made of polygons and I want to take the centroid of each polygon and convert it into raster data and store it in a table.
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1answer
14 views

Deleting small polygons in an sf-object

I have an sf-object (shp downloadable here: https://drive.google.com/open?id=1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT) with multiple glaciers. I want to delete glaciers smaller than 0.05km² by using a for-...
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1answer
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How to delete parts of a multipolygon inside an sf-object in R?

I have spatial data (about some glaciers) as an sf-object. My shp-file can be downloaded here: https://drive.google.com/open?id=1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT Some of the glaciers are separated ...
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0answers
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Join adjacent polygons of an SPDF using gTouches? [closed]

I'm trying to join adjacent polygons in a SpatialPointsDataFrame without merging the whole SPDF into one. The SPDF is a glacier shapefile with some of the glaciers separated into different polygons. ...
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0answers
22 views

Solid is invalid : PolyhedralSurface (shell) 0 is invalid: self intersects

I am trying to calculate the volume of an object with geometry type --PolyhedralSurface. ST_MakeSolid(geom) is valid, while ST_Volume(ST_MakeSolid(geom)) is invalid for the following reasons: ...
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27 views

Finding centrelines from polygons in R sf

Has anyone found a solution for turning polygons into centrelines using R? It has to be in R as I'm deploying it in parallel on a UNIX cluster. I've got as far as: library(sf) centreline <- ...
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QGIS Time Manager with joined layers

I am using QGIS version 3.6 and Time Manager version 3.2.3 to create a temporal map of the US's energy usage over time. I have a polygonal shapefile of the US with each row of the .dbf file containing ...
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19 views

Extract the width/length of a polygon while transforming them to polylines

I've recently started working as a city employee and I've been working on geographic data of the department of mobility. In a project regarding cycling roads we've done an inventory of all the ...
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1answer
58 views

Finding lowest elevation in multiple polygons using DEM? [closed]

I have a polygon layer with six polygons. I need to have the lowest elevation point in each polygon using a DEM. The following explanation https://support.esri.com/en/technical-article/000011761 (...
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0answers
32 views

Esri-Leaflet, Geoprocessing, and Error 500 on return

I'm receiving an error 500 back from ArcGIS Server when I submit a polygon via ESRI-Leaflet. I'm not overly good with Javascript, so I may be missing something obvious - though it's not obvious to me. ...
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0answers
41 views

Creating polygons from binary image using QGIS

Here I got a binary image of buildings (black and white image) and I need to convert them to building polygons: The expected outcome will be a vector file with building polygons based on the image ...
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1answer
31 views

Select polygons which do not contain points

I am able to use the intersect tool to find polygons which overlap with points however I would like to find polygons which do not overlap with any points. I think the Symmetrical Difference Tool ...