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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2
votes
1answer
51 views

Create frequency polygon from overlapping features in another polygon

Mac 10.9.5; QGIS 2.8.4-Wien; history and unioned data, in GDA94, zone 55 here. I have a polygon of fire history with a number of overlapping features. I want to create a new polygon for fire ...
2
votes
1answer
17 views

WFS Filter performed before or after reprojection?

I'm trying to perform a WFS filter with a polygon in EPSG:3031, (the native projection is EPSG:4326 I think). And I'm aware that WFS/GeoServer supports reprojection on the fly. But will the features ...
4
votes
1answer
32 views

How to extract a buffer layer from a vast amount of individual buffers around polygons using ArcMap?

I have a vector layer containing nearly 8000 singlepart polygons. It looks like this: I want statistics on the area that is further than 2,5m away from any border. I thought I could do this by ...
0
votes
0answers
17 views

Extracting coordinates and climatic conditions of grids where species polygon overlaps with the climatic layer in R?

I have species’ shapefiles and climatic raster files. The climatic file is in 50 * 50 km equal area grid. Now, I want to calculate the climatic conditions in each grid cell where species polygon ...
1
vote
0answers
38 views

How to correctly rasterize a polygon which crosses 180E longitude?

I want to rasterize a polygon wich crosses 180E lon with gdal_rasterize. The polygon is in the WGS84 projection. I used the following command: gdal_rasterize -burn 1 -of GTiff -ot Byte -ts 1500 ...
2
votes
1answer
30 views

Catchment boundary polygon from catchment area raster

I am trying to generate a catchment area polygon from a digital elevation model. I am using SAGA tools in QGIS and used the Flow Accumulation (Flow Tracing) tool to generate a catchment area raster ...
3
votes
1answer
42 views

Is it possible to remove small polygons from Census Block shapefile?

I just pulled up a shapefile that plots census blocks (TIGER product) using Quantum and I noticed that there are well over 1000 small polygons that aren't census blocks that are (I assume) used to ...
2
votes
1answer
50 views

Polygons drawn in editable feature service through Collector cause reverse or negative geometry

I have been experiencing a very odd situation where polygons – when drawn in an editable feature service through Collector on iPad – will draw and save, then seconds later the geometry will be ...
1
vote
1answer
47 views

What is the easiest way to create rings from existing polygons?

I have been given a shapefile from a client that features pivots, yet they were recorded as 10 circles overlapping. The software my company uses requires that these polygons be rings that don't ...
1
vote
1answer
68 views

How to map geoJSON polygon from a url request in python

Using Python I have loaded json data from the url http://environment.data.gov.uk/flood-monitoring/id/floods and have found that the flood areas encoded as geoJSON polygons are displayed as url links. ...
1
vote
1answer
29 views

How to assign the attributes of the largest overlapping polygon area to each overlapping gridcell?

I am new to R, and I am trying to use it to calculate the areas of polygons that overlap with each gridcell, in order to assign the attributes of the largest overlapping polygon area to the ...
2
votes
1answer
56 views

Selecting many maximum points within polygons

I've got a point layer with three values such as high, age etc. and polygon layer with many forest area. What I want to do is to select the 100 maximum (highest) points in every polygon. I can't do ...
4
votes
1answer
57 views

Add column to point data of whether point falls inside polygon

This seems like it should be fairly simple, but have been having quite a bit of trouble. I am no expert in ArcGIS for Desktop I have: one layer of points, and 4 polygons, which partly overlap I can ...
2
votes
2answers
68 views

Drawing a polygon of a given area

First, I am using QGIS 2.8.2. I have GPS waypoints and satellite imagery and am trying to draw polygons. This is easy enough, but I need to make sure each polygon is 1ha exactly. Is there a way to ...
1
vote
0answers
21 views

Convert a polygon grid into an edge table

I'm working on a robotics project. I've got a rectangular grid (polygon shape file) that is a navigateable/routable region (i.e. I can travel anywhere in this grid). That is I took my bounding area ...
12
votes
4answers
246 views

How to create lines to visualize differences between polygon features in PostGIS?

I've a PostGIS table polygon_b with some polygon features. There is also a table polygon_a which contains the same polygons as polygon_b but with minor changes. Now I want to create lines to visualize ...
2
votes
1answer
46 views

Can't Find the Split selected features with selected line from another layer tool

I'm trying to split a selected polygon features with a selected line from another feature layer. I, however, can't seem to get the tool for this to show up in my advanced digitize toolbar. In ...
5
votes
3answers
87 views

Merge a list of spatial polygon objects in R

I have a list of spatial buffers (30000 buffers) that I built with the function lapply: buff.pts <- lapply(1:nrow(pts.prj), FUN=function(l){ buff <- gBuffer(pts.prj[l,], width=1000) ## 1km ...
6
votes
3answers
255 views

How to select specific rows of polygons from a grid in QGIS?

I have a polygon layer. I would like to select every second row of the polygons but not manually. Is there an expression to select every second row as seen on the picture with Select by expression in ...
1
vote
0answers
56 views

Problem in polygon division using the union tool from QGIS

I am trying to overlay two polygon layers using the union tool from QGIS, to then compute the areas from the resulting polygons. However, in the resulting layer some polygons are not divided as ...
4
votes
3answers
74 views

Google Earth Polygon surface area to follow the curvature of the earth model

Question: When drawing a polygon in Google Earth with latitude, longitude and elevation values at each node, how do you ensure that the surface area of the polygon also represents the desired ...
3
votes
2answers
56 views

How to calculate area in sq m - troubleshooting projection issues in a global dataset in QGIS

I am using QGIS version 2.12.3. I have 3 polygon shapefiles: A, B and the intersect of A and B, which we can call C. All I want is to add a field to the attributes table of each shapefile giving ...
3
votes
1answer
69 views

How to create a fishnet/grid along a polyline or polygon

I am trying to generate a fishnet/grid along a line/polyline or polygon boundary in ArcGis 10.3 or QGIS. While it is totally intuitive and easy to generate a box-standard grid, what I am trying to do ...
2
votes
1answer
66 views

Converting Shapely MultiPolygon to Polygon: Technique doesn't always work

In order to get the exterior coordinates I need to convert a shapely MultiPolygon to a Polygon. I do it like this: if poly.geometry.type == 'Polygon': x, y = poly.geometry.exterior.xy elif ...
2
votes
1answer
90 views

Grouping polygons by spatial attributes

I'm working with a dataset that contains millions of polygons representing leased properties. In many cases, there are multiple polygons that are drawn on top of one another (representing multiple ...
0
votes
2answers
71 views

Dividing an irregular polygon into sub-regions

I am trying to divide an irregular polygon into equal widths and am having trouble understanding the proper tool to use. I am in possession of ArcGIS and am aware that the Parcel Editor is the closest ...
0
votes
1answer
36 views

How to select congruent polygons in PostGIS?

Title says it all. What is the best way to select congruent polygons in PostGIS? CREATE TABLE polygon_a ( gid serial NOT NULL, geom geometry(Polygon, your_SRID), CONSTRAINT polygon_a_pkey PRIMARY KEY ...
2
votes
0answers
102 views

Merge n number of adjacent polygons [closed]

I have over 17,000 individual polygons. I want to merge two adjacent polygons so that I finish with approximately 8,500 polygons. The polygons need to be merged based on location, merge two adjacent ...
2
votes
0answers
36 views

Geocode area/neigborhood into polygon vertices

I have been successfully using the Google Maps API using the R package ggmap to find location coordinates for e.g. addresses or city names. However, Google Maps now shows areas as well, indicating ...
2
votes
1answer
50 views

Polygon data to Point Feature Data

Using ArcGis 10.0. What I am looking for is a way to get point features that are placed in a polygon to have the same "Address" value. This is the same as the "Spatial Join" feature, however, I am ...
12
votes
2answers
171 views

Project an attribute from one polygon layer to another

I have 2 polygon layers which can be found here. The two layers are overlapping. The first contains a map of the German counties in 1928 and the second the counties how they are in 2014. The 2014 ...
4
votes
1answer
48 views

Edit polygon borders in QGIS preserving topological correctness (planar partition)

Given a layer of polygons that is topologically perfect, i.e., has no overlaps or gaps between the polygons, is it possible to manually edit the edges of the polygons in QGIS in a way that preserves ...
5
votes
1answer
92 views

Find all intersections of a LineString and a Polygon and the order in which it intersects it

I would like to find out all intersections of a LineString (River) through Polygons (Municipalities). I would like to list the order of municipalities which the river crosses, using linear ...
1
vote
1answer
58 views

Hatching over simple fill in ArcGIS 10.3

I have a polygon layer that is symbolized into four categories. Two of these categories are above a threshold limit and two are below. I would like to further distinguish the two categories above the ...
5
votes
1answer
74 views

Aggregating polygons with space between them

Im currently editing a large dataset that has large chunks removed throughout (buffered road network). The areas adjacent from each side have coinciding attributes, but have this large erased area in ...
1
vote
1answer
79 views

Merge polygons in the same shape file based on attributes, ArcGIS or ArcPy

I have a shapefile of polygons. I do not want any polygons with an area less than 25. For polygons with an area less than 25 I want to merge them with another polygon with an area greater than 25 that ...
0
votes
0answers
14 views

Intersect Iso_rectangle_2 with Polygon_2 where Polygon_2 uses Projection_traits_xy_3

I have a set of [Point_3][2] that constitute a Polygon_2 using the Projection_traits_xy_3 typedef CGAL::Exact_predicates_inexact_constructions_kernel K; typedef CGAL::Projection_traits_xy_3<K> ...
1
vote
0answers
83 views

Calculating area of intersection of polygon to another layer in ArcGIS for Desktop?

I am very new to GIS, especially ArcGIS. I am currently using ArcGIS 10.2, and I have 2 layer, namely the purple feature map(this layer is an import from arcgis online, it doesn't seems to be an ...
1
vote
0answers
49 views

Spplot SpatialPolygonDataFrame and SpatialGridDataFrame

I have to plot in the same graph something like this: Then, I have elements from SpatialPolygonDataFrame class and others elements from SpatialGridDataFrame class. When I try to plot them in the ...
2
votes
2answers
53 views

Use function spplot

Does anybody know how to plot with "spplot" fuction two elements of diferents classes?. One element from "SpatialPolygonDataFrame" class and other from "raster" class.
1
vote
0answers
38 views

Selecting certain area of polygon according to size in ArcMap?

I have a set of polygons with a certain size (3500 sq meters each for examples). I only need 3000 sq meters of every polygon. Is there an automatic or semi-automatic way to create sub-polygons out of ...
2
votes
1answer
78 views

Creating polygon regions with latitude and longitude values in qgis?

I've a set of places with their latitudes and longitudes, I've plotted them on QGIS but what I want is to create polygon from these points so that each point refers to a particular region around it. ...
3
votes
1answer
70 views

ArcGIS find all polygons that intersect with more that one polygon from another layer

I have two layers with polygons. I want to find those polygons from first layer that intersect with more that 1 polygon from second layer and find those intersected polygons ID numbers: 1 from first ...
0
votes
0answers
136 views

How to calculate the number of markers with in a polygon in openlayers3

I am using https://github.com/tombatossals/angular-openlayers-directive openlayers angular repository and plotting markers on the map as shown below <!DOCTYPE html> <html ...
0
votes
1answer
29 views

Masking low quality raster with polygons in R gives weird overhang?

I am pretty new to R, and have been attempting to use the mask function on a raster image of 250mx250m resolution. My problem is that for some reason I am getting overhang, as there are pixels which ...
1
vote
0answers
28 views

Polygon to Raster tool while keeping less than maximum values

I'm trying to convert a very large, detailed polygon to a raster with a coarser resolution in ArcGIS 10.1 using the polygon to raster tool. The value field is a percentage and the cellsize must be the ...
1
vote
2answers
62 views

Grouping polygons and other geometrical shapes

My situation: I have administrative areas marked with polygons Many areas have many, many, many islands I need main area and all it's islands to change color when any of the islands or main is ...
4
votes
1answer
82 views

Find out if overlaying polyline matches polygon centerline in qgis

I have a polygon and a polyline and I need to find a scientific way of how close that polyline is to the actual polygon centerline. Is there any way of doing this in qgis? Any extensions, models, ...
1
vote
2answers
87 views

How to combine two polyline shapefile together

Here is my question Two shapefile: * A: represent the outer boundary of the city area * B: represent the inner boundaries of the city divisions. I want to * Combine these two shapefile * ...
3
votes
1answer
82 views

Counting polygons in one layer that are overlapping/touching/contained in each polygon in separate layer of contiguous polygons using QGIS?

I have a layer of contiguous (pink) polygons (UK Parliamentary constitutencies) and a separate layer containing (blue) polygons representing protected nature areas (Natura 2000 areas): Each ...