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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How to interpolate into polygons using ArcGIS Desktop?

I need to interpolate values from points to polygons. I have a point shapefile and a shapefile of adjacent polygons. Some polygons get several points falling inside, some have nothing. I thought ...
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1answer
90 views

Clipping features depending upon percent coverage by other features

I have a shapefile composed of several thousand square polygons of equal size, arranged in a grid. I have another shapefile with a few dozen circles. The squares are about 1/10th the size of the ...
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2answers
189 views

Why does qgis give multiple centroids per polygon?

I have a shapefile for the boundaries of European NUTS regions, and I would like to compute the centroid for each of those regions. When I do this in QGIS (2.6.1 on OSX, using polygon centroids from ...
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2answers
599 views

Need an Algorithm to Determining Polygon Borders

I'm currently writing a program in Java and I'm dealing with polygon objects. I want to create a different color border between touching objects depending on their class (i.e. land, ocean, etc). I ...
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2answers
878 views

Is it possible to generate a vector polygon from a polygon on a raster image?

I have a raster map which I have extracted from a government report providing flood extent return frequencies. I want to 'snatch' these flood extent polygons (i.e. convert to vector) and I was ...
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Including polygons as part of network for ArcGIS Network Analyst?

I am creating a pedestrian walking network of a downtown area. I am digitizing line segments for paths and sidewalks, but I need to incorporate parking lots into my analysis. So far, I have been ...
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3answers
164 views

Smoothing method for big polygons

I'm looking for an alternative to 'snakes method' for smoothing very big polygons, which I created from SRTM elevation datasets. The problem is that the smoothing is getting stuck after a while with ...
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1answer
153 views

Adding new nodes in the middle of each líne of a Polygon

I am currently working on a Street Lighting Network. I have two layers in PostGIS ( PostGIS 2.1.3 and PostgreSQL 9.3.5): Manholes (56.000 Polygon) Pipes (Linestring) The manholes are perfect ...
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1answer
89 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 ...
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2answers
267 views

Is it possible to clip a shapefile to an image() in R?

I am working on mapping some netcdf data in R and have been having a tough time trying to perform a clip with an imported country shapefile that I'm using. Here is my question from yesterday. If you ...
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1answer
195 views

Create shapefile of raster outline using python

I want to create a single bounding shapefile polygon of valid pixels in raster data (GeoTIFF) using python. I need something efficient as I need to do this for hundreds of rasters. I had thought of ...
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2answers
154 views

Polygon points to Polyline

I am trying to create a polyline from the points that I query from a polygon. I have a polygon, and I am getting its edges, casting them to segments, and then use QueryNormal to get the mid point ...
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1answer
1k views

Leaflet JS add GeoJSON shape as a hole in a polygon

I have a dataset which already contains geojson. I can add it to my map with the following line of code. L.geoJson(data.geojson).addTo(map); And I get this But I want to achieve this, where the ...
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2answers
387 views

Calculating edge length of polygon within overlapping polygon

I have a layer of wetland polygons and a layer of lakes. I basically want to find the total length of lake shoreline contained within each wetland and add these values as an attribute of the wetlands. ...
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1answer
952 views

Shapefiles - Polygon type - is it in fact multipolygon?

I'm wondering about the ESRI shape file with shape type 5. When reading the spec I see that "A polygon may contain multiple outer rings.". Does this mean that these outer rings must be combined to ...
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1answer
613 views

Create MultiPolygon from QgsGeometry.fromMultiPolygon

I have a list of polygons' points like [[x1,y1],[x2,y2],[x3,y3],[x4,y4]] [[x5,y5],[x6,y6],[x7,y7].[x8,y8]] now I want to create multipolygon from it by using feature = QgsFeature() feature....
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1answer
2k views

Create a new vector layer that fills space between other polygons in QGIS

I inherited a clipped (500m radius) land cover map containing vector layers of different land cover categories such as buildings, grass, roads, etc from a colleague. The empty (white) space in ...
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2answers
1k views

How to enclose clustered points with polygon?

I have a raster with forest (1), no forest (2) data. "1" is represent single/few trees and there is gaps between them. I want to create a polygon around these trees to a forest map. It is not a dense ...
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2answers
4k views

Removing sliver polygons in ArcGIS Desktop?

I unioned 2 layers into 1 layer, and it created sliver polygons. I used the elimination tool to merge them with neighboring polygons. As as result, it merges all sliver polygons to only one polygon (...
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1answer
1k views

How to create a polygon from other polygon boundaries?

I want to write an algorithm that creates a polygon inside a hole made by a set of other polygons. It's something like a flood fill and it's like the "boundary" tool in Autocad. The image shows an ...
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1answer
143 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 referencing....
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1answer
1k views

Count overlapping polygons in single shape file with R

I have a shapefile of species ranges for ~ 346 species. Some species have multiple polygon ranges so there are 1,078 polygons and many polygons are multi-part. It looks something like this: I ...
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2answers
901 views

Clip polygon and retain data

I have these two polygons: library(sp); library(rgeos); library(maptools) coords1 <- matrix(c(-1.841960, -1.823464, -1.838623, -1.841960, 55.663696, 55.659178, 55.650841, 55....
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4answers
902 views

How to computational efficiently check if there are any overlapping polygons in a group of polygons?

I need to do some processing with groups of polygons. If any of the polygons in the group overlaps other polygon the result is unpredictable and don't throw any error. So, I need to detect if there is ...
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1answer
107 views

How do you edit a stack of polygons simultaneously?

Using ArcMap 10.1. Lets say you have 100 polygons that all are in the exact same shape and in the exact same place. They appear to be one polygon. How would you edit the shape of all 100 at the same ...
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1answer
3k views

How to calculate polygon area considering slopes?

I am looking for an accurate algorithm or a service to calculate surface area on earth where points are calculated on the basis of GPS Coordinates. I am using Google Map Api version 3 and are drawing ...
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3answers
2k views

Calculate neighborhood statistics for polygons?

I've been searching around for the answer to this (including here) and have yet to find it. I'm interested in finding out how to calculate a 'neighborhood sum' for vector, polygon data. I am aware ...
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1answer
206 views

Generating surfaces of different heights from LIDAR points

I am seeking a way to generate surfaces (polygons in a 3D space) of different heights from LIDAR point clouds, whose spacing is 4 points per square meter. The typical application is like roofs, which ...
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2answers
1k views

What methods exist for geohash of polygon?

GeoHash is an excellent method to code the latitude and longitude of a point into a string. It's concise, due to the use of numbers + letters, and the precision can be tuned adding characters at the ...
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2answers
361 views

How to calculate the area between two line shapes?

I'm a newbie using QGIS (2.0). I'm trying to calculate the sidewalk area of a city. For that I have some shapes, extracted from Mricostation, with the topology (facades, fords, fences, etc.), but ...
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1answer
79 views

Geographic locators within Polygons

I have a list of geographic locators and a boundary file. In QGIS, is there any way merging them together to create a lookup saying this boundary contains these locators? Not the number the actual ...
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1answer
2k views

How to automate the drawing of polygons (square) around a number of points in QGIS?

In QGIS (or alternatively any other scripting + GIS stack), how can I automate drawing a 100km x 100km square around a number of points, with the point being dead in the center? I'd need to loop ...
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2answers
2k views

Export selected raster cells to polygon

I have selected certain values in a raster (roughly 1000 cells), and would like to export them to be able to create a polygon. Converting it to points first then to polygons does not work. Can anyone ...
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1answer
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How do I split polygons that cross the dateline?

I have a dataset of country borders which I obtained from: http://thematicmapping.org/downloads/world_borders.php/ I have that dataset in both shp and SQL, but I'll put out there that I don't feel ...
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1answer
302 views

algorithm for displaying holes in a polygon by translating it into several hole-less polygons?

I'd like to plot polygons with holes on a framework that doesn't support holes. The approach to me seems to be to translate the single polygon into several ones adding up to the whole polygon, leaving ...
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2answers
107 views

Identifying a cluster of polygons based on attributes

I'm trying to identify a cluster of contiguous parcels that, when combined, add up to at least a given size and, when combined, have an assessed property value less than a given $ amount. I have a ...
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1answer
787 views

Create raster with grid cells values based on area covered by polygons

I have a polygon data with area covered by the forests (data is here - https://www.dropbox.com/s/zgckliydalljw6a/sp_data.zip?dl=0). I want to convert polygons to raster. The value of each grid cell ...
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3answers
494 views

How to combine stacked polygons within a shapefile?

The image below shows my shp-file. Every polygon has the same transparent color. So a darker blue means, that several polygons are stacked! How do I cut every polygon with each other so no polygons ...
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3answers
756 views

Polygonize vegetation area from Landsat7 RGB using QGis / Bilko?

I'm trying to extract the areas with vegetation as a polygon-shape from a landsat7-image, 30m resolution, RGB, using QGis 1.8 or Bilko or (hopefully in the near future) ArcGIS. The area is in Northern ...
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0answers
58 views

How to decide the master part when you cut a multipart polygon? [closed]

I am splitting parts of a multipart polygon in an ArcMap edit session using the cut polygon tool. Is there any way to decide which is the part that will remain multipart and which is the part that ...
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0answers
99 views

Split polygon by area using ArcGIS for Desktop (or QGIS)? [duplicate]

I'm interested to split a larger, irregular polygon into smaller ones. I know the area of the resulting polygon, and I know that the line I want to split it by should be parallel to one of the sides ...
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0answers
190 views

Is there a limit to the number of polygon points you can export to CSV in QGIS 2.4?

Using QGIS 2.4 I am currently importing a csv file with ~30,000 polygons (polygons in WKT format). I also have a United States shapefile. I have used the Clip function to get only the polygons that ...
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0answers
138 views

Why doesn't Polygonizer copy the line ids to my polygonized shapefile?

I am trying to convert a line shapefile into a polygon shapefile using Polygonizer plugin, and when my new polygons are created all the cells in my id field are "Null", although I have clicked "copy ...
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0answers
221 views

How to rotate polygon to find best fit in Mapnik? [closed]

I have a quite simple problem but somehow I just fail to solve it. There is a polygon and a range xsize and ysize. The x and y size determines the mapnik generated image. The polygon should now be ...
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5answers
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Counting road intersections and blocks

I have a shp file that consists of the road system of Mexico City. I would like to count the number of road intersections (crossings) and blocks (which I would define as a segment starting from one ...
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5answers
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Simplify shapefile parcel layer

I have a very large shapefile with over a million parcels within it. The problem I am having is that the polygons representing each parcel are very jagged. What I am looking for is a simple and fast ...
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2answers
4k views

How to Select “Inverse” of intersection of two polygon layers?

I'm wondering if there's a way to intersect two polygon layers, take the intersection, and remove that from one of the polygon layers, making a new layer out of whatever is left over? Basically, the ...
4
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3answers
429 views

How to count the sides or edges of a polygon?

I wondered if it is possible to determine the number of sides / edges (not vertices) that a polygon has. Imagine the following case. There is a shapefile with 10 polygons. Is there any way to ...
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1answer
6k views

Creating polygon based on spatial extent in ArcGIS Desktop?

Is there anyway that I can input: The Coordinates System (projected is OK) The bounding box and create a rectangle polygon based on these?
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2answers
1k views

Displaying adjacent polygon lines beside each other instead of overlapping

I would like to display adjacent polygons with the line work beside each other, not one on top of the other for that shared boundary. I do not want to edit the polygon boundaries - only want to ...