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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2answers
30 views

Calculating proportional area of polygon covered by circle

I have two layers here (ignore the green layer), blue polygons and black circles. I want to calculate for each circle, what percent of the each of the blue polygons does it cover. For example, the ...
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38 views

Merging two isolines into one in PostGIS

How can I sum 2 isolines A and B (closed linestrings with values) into one isoline C with summed values on common parts? For each line string there is a value and I would like to sum on common part. ...
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1answer
57 views

Grouping country polygons into a region without dissolving borders

PowerBI allows for the import of a shapefile via JSON to create a map for data visualization. In PowerBI, I want my users to be able to select either a single country or a region that contains that ...
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1answer
44 views

Fully cover polygon with circles of fixed radius?

I have some detailed polygons I want to cover by generating points buffered to 4km radius. How do I determine the best way (or even a decent) way of covering the polygons completely with minimal ...
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0answers
14 views

Dividing region in 9 sub-regions in Google Earth Engine

I am studying the spectral response of PV plants in GEE. I need to divide a polygon (geometry), which is shaped like the plant, in 9 sub-polygons, to investigate how each corner of the plant reacts. ...
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1answer
29 views

Splitting up polygon with grid using QGIS

I am using QGIS. I have a county map as a single polygon, it has one FEATURE in which one FIELD is Area. I have a grid which also a polygon that divides the county into squares and each grid square ...
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0answers
23 views

How can I fix misshaped GeoJSON polygons?

In 2018 Ghana changed its administrative divisions (from 11 to 16 regions, and from 216 to 260 districts). Unfortunately, I have not been able to find the GeoJSON (or equivalent) data for the new ...
6
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1answer
72 views

Determine roundness of polygon in QGIS

Suppose a polygon layer in QGIS with differently shaped polygons (no multi-geometries, let's keep it simple). Is there a way to calculate some kind of roundness characteristic of the individual ...
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1answer
53 views

Merging some polygons when creating Virtual Layer

I have a polygon layer 'lot' containing an attribute "lot_number". Then, I want to create a Virtual Layer that merges some of the lots while keeping others separated, as the diagram shows ...
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2answers
62 views

Creating Virtual layer that is the centroid of another polygon layer

There's a polygon layer building and I want to create a point layer centroid containing centroids of building layer. I have 2 more requests: to keep all attributes in the building layer in the newly-...
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0answers
32 views

Create road blocks from streets layer/ creating lots from streets and centroids [closed]

My real task is to create an layer of lots. I'm supposed to do this from 2 layers available to the area in question: 1 layer of streets (line) 1 point layer containing the centroids of those lots I'm ...
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0answers
10 views

Developing a map-based 3D polygon application [closed]

I am new to GIS. I am looking to develop an application where a user can choose a 3D terrain map (TIN) of anywhere in the world, and choose a point, and the application will draw a 'circle' - create a ...
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2answers
40 views

Dissolve of polygons leaving internal lines

I have been trying to produce an outline of a stylised island using dissolve however there are internal "lines" that remain after I use dissolve? The hexagons that are being merged were ...
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1answer
43 views

Find distance between two points by following a polyline in R

I have a polyline shapefile that follows the center of a stream, and I have coordinates for animal positions within the stream (not necessarily immediately on the line), and I am trying to calculate ...
2
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1answer
37 views

Interrogating and displaying polygon created from points in PyQGIS

I've been working on this problem for several questions now - the most recent one here. I believe the code below had created the polygon from the points, and added this polygon to a layer as a ...
7
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3answers
253 views

Creating polygons with fixed extent based on point which represents S/W corner using QGIS

I have a point data set which contains the information of workplaces per hectare. Each point represents the South-Western corner of the surveyed hectare. Not the entire map is covered with points, ...
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0answers
26 views

Simple way to convert GeoJSON from MultiPolygon into Polygon [duplicate]

I need a GeoJSON file that simply has the coordinates of the polygons for the boundaries of the provinces of Canada. I have a GeoJSON file but it has multipolygons and my software does not support ...
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2answers
79 views

Spatially join attributes from point to polygon side with numerous contiguous polygons and numerous adjacent points

I have been trying for 2 days to join points representing addresses (in Paris region) to the closest polygon (parcel of land). The problems: The parcels of land are contiguous, sometimes a point ...
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0answers
13 views

Online source of polygon nodes for individual newly created zipcodes

When a new zipcode is created it would be very convenient to obtain its polygon nodes from an online source, without having to download a national dataset. Does an online web-page or web-API exist, ...
0
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1answer
41 views

Getting area (in square meter or km) of polygon in MySQL 5.6

I have a table in MySQL that has polygon defined. Read MySQL 5.6 geospatial index documentation and came across ST_Area function. Tried to dig into the units which are computed as per the spatial ...
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0answers
14 views

Merge two adjacent polygons in a 3D space [closed]

Given two three-dimensional polygons that are both in the same winding order (counter-clockwise order or in clockwise order): poly1 = np.array([[120787.075999871, 491779.675000143, -2.0699999332428], [...
3
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1answer
40 views

Generate points inside multipolygons using GeoPandas

I have a shapefile which has multipolygon geometries. I want to generate random points inside them using GeoPandas. I tried with the below code but it's not giving geodataframe of points. df = gpd....
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0answers
25 views

Inserting/Update a polygon into a field with null geometry in Oracle

How can I copy a previously created polygon that is in a temporary layer, to a field with null geometry in Oracle? I can view the field in the table, use the "Add Part" tool to create a new ...
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1answer
40 views

Spatial join with GeoPandas with two geometry columns

I have one GeoDataFrame which contains two geometry fields - one is polygon and one is the polygon centroids. The table has also other fields. I have run spatial join between the gdf and another ...
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1answer
28 views

QGIS average/mean Z-value of polygon

I am trying to derive an average/mean Z-value of the GPS measured polygons. The standard z($geometry) I use for point layers doesn't work obviously. I could use z(start_point($geometry)), but that is ...
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1answer
23 views

Crosshatched fill for polygons in overlapping categories in ArcGIS

I have a polygon layer whose color needs to represent certain categories. There are a couple of polygons that belong to two categories at once (in the attribute table, the relevant cells literally ...
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0answers
30 views

raster::crop not working as expected

I'm trying to crop a raster stack using a polygon. structure(chelsa_envs) class : RasterStack dimensions : 20880, 43200, 902016000, 19 (nrow, ncol, ncell, nlayers) resolution : 0.008333333, 0....
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1answer
34 views

ST_GEOGFROMTEXT Multipolygons converted to Polygons BigQuery

My table contains multipolygons in column called BoundaryWKT, which is in a string format. I used function ST_GEOGFROMTEXT(BoundaryWKT) to convert column of multipolygons from string format to a ...
2
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2answers
73 views

Representing Polygon Complexity as readable attribute [closed]

I'm using QGIS and I have polygons such as this I would like to generate a feature table with the point in each polygon, and a sort of 'encoding' of the corresponding polygon. I would like to ...
6
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1answer
113 views

Efficient clipping of polygons by other polygons using R

I have a dataset with overlapping polygons. I would like the clip the overlapping polygons (which I need to retain as overlapping) to a boundary (another polygon). I am using sf and st_intersection ...
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0answers
34 views

Alter Rectangle Polygon by Keyboard to Have Specified Dimensions (eg 1km x 1km)

Here is my current workflow. Press "New Shapefile Layer" with "Geometry type": "Polygon" Press "Toggle Editing" Press "Add Rectangle from Center and a ...
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3answers
39 views

Merging polygons into one single feature

I have 73 polygons of Protected Areas, and I want to merge this into one single feature of protected areas and calculate area total of all of them, I tried using the merge tool, but I keep getting the ...
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0answers
22 views

Converting polygon with latitude and longitude to x y plane

I have a polygon (shape of a building) containing coordinates as latitude and longitude. I need to convert them into an x-y plane. I have used various methods such as: const R = 6.371; const x = R * ...
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1answer
18 views

Adding temporal attributes of larger polygons onto many smaller overlaying polygons

I am currently working with rainfall data on a large grid layer and want to transfer the data onto smaller grids. In the image below the large blue polygons currently have the data stored in them and ...
2
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1answer
35 views

Find out points outside the polygon

I have a shapefile with geometries of different regions. Also I have a list of coordinate points(field_lonlat), I want to consider only those points of the list which are outside the polygon ...
2
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2answers
58 views

Difference between two features in same polygon in QGIS

I have a polygon and some features are below another features. If I would have two different polygons I would use the "Difference" tool so it would take the overlapping feauters to the "...
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0answers
21 views

Identify multiple polylines in one polygon (ArcGIS)

I have coastal city polygons, and one polyline with a numeric attribute (X) that I am interested in, which ranges from 1-9. One city can have diverse values of X. My final goal is to have one table, ...
2
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1answer
47 views

Checking if result of st_difference is empty

I am trying to select lines that completely touch a polygon (not at just a single point). I would assume it would be a simple case of st_isempty(st_difference(geom_a,geom_b)). However, this is not the ...
1
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1answer
32 views

Change Stroke Width of a Polygon PyQGIS

I'm trying to set the Width of the lake's contours to zero or change the color to light blue, since the I dont want to see the black outline. The vector file is a Polygon (MultiPolygon) named vlayer2 ...
1
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1answer
23 views

Extracting categorial data from neighboring polygons from st_intersects [closed]

For each polygon in an sf object, I need to extract data on a single variable from all of the neighboring polygons. I have made a reprex below. So far I have managed to get a list of the neighboring ...
0
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2answers
62 views

Finding median value of many points within polygon using ArcMap

I am using ArcMap version 10.7. I have 2 layers, one point and one polygon (council district boundaries). The polygon layer has several polygons in it and each point has a dollar amount associated ...
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0answers
27 views

Distance between two points within a polygon (or raster value) in R

I'm trying to get the shortest distance between each point in a a set of coordinates (lat/long) within a body of water. However, straight line distances don't work because the points represent the ...
2
votes
1answer
33 views

Spatial join and sum aggregation of two polygon GeoDataFrames in GeoPandas

I would like to join two GeoDataFrames with polygon geometries (purple and green, see screenshot below). However, I would like to get the sum of all intersecting green areas per purple feature they ...
1
vote
1answer
20 views

Casting LineString to Polygon results in ClassCastException when y coordinates are the same

final WKTReader wktReader = new WKTReader(); String geomString = "MULTILINESTRING ((-98.753985 34.63093, -98.7555568 34.63093))"; MultiLineString geom = (MultiLineString)wktReader.read(...
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0answers
31 views

Creating an intersection (mix of offset and buffer) of 5m on each polygon feature in QGIS [duplicate]

I'm trying to reproduce the steps needed to aim this goal: Given a layer of polygons, I'm want to retrieve for each polygon which is at a distance less than 50m to a 2nd polygonal layer the only 5m ...
1
vote
1answer
55 views

Orient OpenLayers 6 labels along longest side of a polygon

I'm using OpenLayers with the EPSG 3857 Coordinate System and I want my polygon labels to be orientated along the longest side of the polygon. The labels in OpenLayers are aligned horizontally by ...
1
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1answer
39 views

Automatically measure shape length in km

I have a large number (>1000) of polygons in a shapefile. I would like to measure their approximate length. The polygons are somehow elongated, so a quantity such as the length of longest line ...
1
vote
1answer
21 views

Unable to process multiple polygons using SpatialPolygons object

I have a list with 4 objects, each object is a data frame. The data frame is the coordinate matrix of each polygon. I would like calculate the total area of the 4 polygons and then draw the voronoi ...
1
vote
1answer
23 views

Highlighting terrain only between defined elevation range [closed]

I am trying to highlight terrain between two elevations in order to highlight where certain plants could be found. For example if a plant in found in a certain valley between 600-1200m, I'd like to be ...
0
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0answers
20 views

How do I draw polygons from aerial imagery?

I will be working on a project to automatically identify ponds from satellite imagery. I have uploaded the basemap into ArcMap 10.7, but I can't create a feature layer to start editing. How do I add a ...

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