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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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20 views

How do I re-project a shape file from WGS84 to World Sinusoidal?

I have a polygon shape file which is on WGS84 and I want to re-project it on EPSG:53008 (World Sinusoidal). When I'm trying to do it either by 'Save as' or by 'Data management tool' it says that the ...
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0answers
15 views

Polygonize and mask a GeoTiff with GDAL and OGR

I am trying to polygonize a GeoTIFF: import numpy, sys from osgeo import gdal, ogr from osgeo.gdalconst import * gdal.UseExceptions() ds = gdal.Open('H:/Threshold/nsdvi_range.tif' srcband = ds....
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1answer
7 views

GeoServer - WMS v WFS (polygon label issue)

I am hoping that when I switch over to WFS that my multi-polygon labelling issue will disappear. Currently I am using WMS, and I believe the reason I am seeing multiple labels within my polygons is ...
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1answer
33 views

Cutting rasters using polygon and obtaining pixel specific data using ArcMap

I have a georeferenced polygon file that I want to use to cut several different raster files. I am looking to analyse the individual pixels within those cut areas. One of the raster files has a ...
6
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2answers
3k views

How to split a polygon using R

I have an irregular polygon which is a spatial object. I want to divide it into multiple polygons (say, n=25) with equal height. To show how I want to divide it, I've plotted grids on the background ...
2
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2answers
47 views

Tool in QGIS to construct polygons based on network of lines

Is there a tool in QGIS similar to "Contruct polygons" in ArcGIS that creates polygons from existing lines? This is different from convert lines to polygons that requires closed loops (minimum of ...
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1answer
20 views

ST_Contains always return false

I'm definitely a 'geonewbie' and I'm trying to test if a point is contained inside a region. I have taken some certified data here: https://www.istat.it/it/archivio/124086 getting WGS84 UTM32N for ...
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0answers
11 views

Forming rectangle between two diagonal points using MySQL?

I've been working with Google Maps a bit lately and they provide a set of bounds (two points, northeast and southwest). ex. "bounds": { "northeast": { "lat": 34.111236 "lng": -118.2840872 ...
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1answer
34 views

Identifying polygons in two separate layers with a large (>85%) overlap

I have two separate layers and I want to identify polygons that overlap more than 85%. When I try "Extract by location" tool it gives me the polygons that overlap even in small areas. I am using QGIS ...
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0answers
38 views

How to drill polygons within one layer, ArcGIS 10.3

I have a one layer that has multiple polygons sitting on top of each other. Is there any tool to drill all the polygons between each other?
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0answers
37 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 ...
3
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2answers
181 views

Creating polygon from hole in QGIS?

I work with this polygon and try to find a way to create a new polygon from the empty gap in the middle of the polygon. I succeed to do it with a "difference" tool- but used with another layer on the ...
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1answer
16 views

How to free the memory of return value of OGRGeometry::Buffer()?

I have in C++ (gdal 2.3.2) OGRPolygon poly; OGRGeometry* geom = poly.Buffer(1e-12, 1); now how do I free the memory allocated for geom after done using it?
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1answer
38 views

Rearrange plotorder of SpatialPolygonsDataframe

I have a SpatialPolygonDataframe (loaded with readOGR) I want to plot in either tmap or leaflet. A lot of the polygons are overlapping, and the smaller polygons are completely covered by larger ...
3
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0answers
141 views

Create perimeter from given area [closed]

I need to develop a web-based application to manage areas inside a bigger area. I already have the initial perimeter, and it has irregular borders like that: . I will need to tell the app to ...
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1answer
43 views

Using centroid point to generate polygon using ArcPy? [closed]

Is this possible to generate polygons from points (which are centroids of future polygon)? I got shapefile with ~250 points + they have got two attributes: length and width. I don't need complete ...
1
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1answer
35 views

Two adjoining lines becomes clearer than two individual

When having an outline style where the two edges interfere, they become much more dense in the color than when they are individual, see image below. It is an outline of a polygon. The thing is that ...
2
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1answer
41 views

Expanding Polygon by distance using PostGIS?

I am trying to expand a polygon in a particular manner with PostGIS. I need a new geometry that is a bit like a Buffer, except Buffer produces rounded corners (lots of vertices) when using it on a ...
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0answers
219 views

Merging polygons of single feature using QGIS? [closed]

I am new to QGIS and have done some research on this topic before posting but not sure I found an answer. I have one feature that has multiple polygons (islands of a nation). In reality, there is ...
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1answer
62 views

Lines in Polygon Analysis

This question is similar to the "points in polygon" analysis, but I want to keep the attribute data for multiple lines within a single polygon. The data source is multiple line segments representing ...
2
votes
1answer
28 views

Distance from edge of each polygon to nearest point, such that points within each polygon aren't included

Using ArcGIS 10.5, I have a cluster of polygons that represent districts (together this cluster of polygons creates a nation). I also have thousands of points that represent offices. I would like to ...
2
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0answers
26 views

Graduated color display of overlapping polygons in ArcMap

Is there a way to display overlapping polygons in a graduated color symbology based on the level of overlap within the same feature layer? For example, in one area of the map there are two polygons ...
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2answers
696 views

Join Point to the Nearest Polygon

I'm using QGis 2.18.3 on Windows 10. I'm trying to join a point layer with a polygon layer. However, since it is a city grid map, points that do not fall within the polygons do not get joined. My ...
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0answers
10 views

R Clip Simple Features Multiple Polygons with a Polygon (or another multi-polygon)

I have two polygon layers, a set of aquifer polygons and a set of district boundaries. I'm trying to clip the aquifer layers to be in only the districts that I want. From examining the other posts ...
2
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1answer
40 views

Cleaning topology errors in PostgreSQL (vector data) using QGIS?

I need to append the shapefiles to a PostgreSQL database. Once the data gets appended to PostgreSQL, some topology errors like gaps & overlaps can be seen. By using the v.clean tools the topology ...
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0answers
33 views

Erroneous contour polygons in QGIS 3

I have a global DEM and try to calculate contour polygons for 4 different heights in QGIS. In the first image below, you can see the colored DEM (white = lowest; yellow = higher; orange = highest) as ...
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1answer
26 views

Exporting Polygons (RGB color bands) nto CSV

I have drawn ~40 polygons over NAIP imagery to collect their R, G, B color bands. I now want to export each polygon with its associated RGB color values into a CSV file so I can plot the polygons ...
3
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4answers
3k views

Getting Clip raster ERROR 1: Did not get any cutline features?

I want to clip a raster using a polygon I made. However, I get the following error message. I've tried all the possible options but somehow I'm not being able to clip it. QGIS 2.16.2 on Windows 10
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0answers
28 views

Edge matching polygons

I am trying to match the edges of two polygon layers. One is Orleans county, NY and the other layers is Monroe county, NY. Since the Orleans county is from a different source, the boundaries are not ...
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2answers
77 views

Connect multipart polygon with lines to one label

I have several one-part and multipart polygons that I want to label. I Set X and Y values to move the label to a certain position and want to connect the label to the polygon using the following ...
0
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1answer
74 views

Filling polygon with png pattern in OpenLayers?

I want to fill a set of polygons with png pattern. Here is an extract of my code : var canvas = document.createElement('canvas'); var context = canvas.getContext('2d'); var pattern; var imageObj ...
3
votes
1answer
264 views

How do I split polygon in equal parts based on polygon area?

So, I came across this relevant question, but I think my problem is a bit different. I have two tables i.e. polygon poly and points pts in my Postgres db. I am on Windows 10 (x64) based machine and ...
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1answer
42 views

Export MultiPolygon data as WKT from QGIS 3

I have the polygon data for the city of Kamloops in QGIS 3. When I try to copy features of this polygon and try to paste it over here: https://arthur-e.github.io/Wicket/sandbox-gmaps3.html I don't get ...
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3answers
6k views

How to create a multipart polygon?

I have two polygons that consist of two separate polygons/lines in QGIS). How can I make this into a multipart polygon, which consists of 1 line in QGIS?
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0answers
13 views

PAEK smoothing tolerance

How should one determine what the Polynomial Approximation with Exponential Kernel smoothing tolerance should be when smoothing a shape file using the Smooth polygon tool
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0answers
244 views

How to estimate the average width of a sidewalk? [duplicate]

I have a table with two polygons representing urban block with and without the sidewalk: geomBlock and geomBlockWithSidewalk. On my city we can approximate the polygons of geomBlockWithSidewalk to a ...
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1answer
80 views

Spatially joining small target feature to one of multiple join features using ArcGIS Desktop?

I am trying to spatially join characteristics from a larger unit (here: county) to a smaller unit (say, local district), such that for every local district I will also know in which county it is in. ...
4
votes
1answer
108 views

Fix slivers (Holes) between polygons ( generated after removing spikes)

I am trying to fix topological errors in this Shapefile of small areas of a state (Bahia) in Brazil. After applying prepair and PPrepair, the resulting shapefile has some spikes: It looks like a like ...
2
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0answers
15 views

Removing a 'non-gap' gap from a polygon that straddles +/- 180 longitude; looking for an R-based, code solution

I am working with a set of polygons from here: http://lme.edc.uri.edu/index.php/digital-data. In the artic, there are several polygons that straddle the +/- 180 longitude line. These are single ...
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1answer
430 views

cannot get properties of multipolygon - mapbox/leaflet

I'm currently using mapbox with natural earth and geojson to populate a map with multipoygons and custom markers. Each of these has a set of properties and information that I need to display on click -...
4
votes
1answer
287 views

Determine whether a polygon crosses the antimeridian

I'm working on a system that uses bounding boxes as a fast first check for a point-in-polygon filter. My current naive implementation (just taking the min/max lat and lng for all points) fails on ...
4
votes
2answers
421 views

Creating voronoi polygons from polygons?

I have a database with buildings and for some further analysis I need to: aggregate adjacent buildings (preferably without losing the height attribute, but I can work my way around that) once I have ...
2
votes
2answers
76 views

Cannot select polygon from shapefile in QGIS?

I am working currently on a small-scale map using among other sources Natural Earth shapefiles (NE). For an unknown reason, one of the polygons created by me on the basis of the fragments of NE ...
24
votes
9answers
60k views

Extracting coordinates of polygon vertices in ArcMap?

I've got about a dozen polygons in a feature class loaded in ArcMap 10, all in geographic WGS 1984. How do I easily obtain the coordinates associated with each vertex of each polygon in that feature ...
0
votes
1answer
50 views

Vectorizing black and white PNG? [closed]

I have a PNG map with just black and white colors, where black is the one pixel border. I want this in vector, or want an easy way to draw 90 degree polygons. I tried some things from forums but I ...
1
vote
1answer
77 views

Generate tiles from leaflet polygons

I have a set of shapes drawn in Leaflet (using Leaflet.draw). I need to rasterize these into a tileset and export it because I need to use the images elsewhere. My initial idea was to go through ...
15
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2answers
14k views

How to perform a true GIS clip of polygons layer using a polygon layer in R?

I would like to do a true GIS Clip in R of soils polygons using a series of single boundary polygons, but I cannot find an R function to properly do it. It should work just like the clip function in ...
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1answer
59 views

Change attribute of a line according to overlapping polygon features

I'm pretty new to QGIS and python in general. For my work I'm faced with a bit of a problem. I got 100-m-segments of several streams and polygon-features of the surrounding substrate. The polygon ...
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1answer
91 views

Plot times series for stack raster based on a polygons in my area

I am using R language and I would like to create a EVI MODIS time series plot, EVI vs time. I can did method to create a raster stack and plot the average EVI of the total area over time. But I ...
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1answer
148 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 ...