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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1answer
73 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
183 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
159 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
134 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 ...
5
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2answers
332 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. ...
5
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1answer
562 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() ...
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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 ...
5
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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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2answers
745 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, ...
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4answers
862 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 ...
5
votes
1answer
106 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 ...
5
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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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votes
2answers
342 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
1k views

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
293 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
78 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
657 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
466 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
731 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
50 views

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

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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97 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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150 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
137 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
215 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 ...
4
votes
2answers
9k views

How can I split a multi-part polygon into single polygons?

i want to split a multipart polygon which consists of several polygons into single polygons so I can delete each polygon without deleting them all at one time. I am using ArcGIS 10.
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5answers
2k views

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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4answers
2k views

Is there a way of auto_increment for the ID column in QGIS

I'm creating a fictive map and so I need to create lots of points, lines and for sure polygons. Later on I export my data as geojson. But before that I aways have to go and give every element an ...
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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
votes
3answers
393 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 ...
4
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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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4answers
71 views

How to change feature draw order in QGIS?

Probably a very basic question here, I want to change the draw order of a shapefile in qgis, how can this be done? As you can see in the picture below, only the "10" layer is shown, but since this ...
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4answers
33k views

How to connect points with a polyline in ArcMap 10?

I have a layer containing a few hundred points representing a survey track. The points are laid out in chronological order in the corresponding attribute table. How can I have ArcMap 10 automatically ...
4
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2answers
82 views

Manually selecting colors for different polygons within layer in ArcMap?

There is a polygon layer with several polygons. They are displayed with some colour which can be changed simultaneously for all of them. Is there a way to manually select several polygons (without ...
4
votes
1answer
2k views

How to find markers in selected dragbox openlayers 3?

Here is a part of code, draw = new ol.interaction.DragBox({ /* dragbox interaction is active only if alt key is pressed */ condition: ol.events.condition.altKeyOnly, ...
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votes
2answers
998 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 ...
4
votes
3answers
225 views

How to shrink polygon on two sides?

I have a polygon which I know is a rectangle, although it may be at any orientation: I want to shrink this polygon by a third of the width from two sides, so that I just get the strip in the middle ...
4
votes
1answer
128 views

What is the best format to encode polygons such as lakes?

I am looking for a standard format to encode polygons, such as lakes, in one file that is easy to create and common so that others can use it in different GIS systems. Every file will contain data on ...
4
votes
1answer
2k views

How to add CSV data with no coordinates to a polygon layer in QGIS?

I would like to add attributes from an spss database (around 300 cases) to a polygon layer in QGIS. Both datasets have a column with unique IDs. I exported the spss data to a CSV file which does not ...
4
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5answers
1k views

Python loop Polygon to raster not working

I want to convert a large number of different shp polygons to raster in ArcGIS 10.1, using an existing field column "class" for the new raster classes. I am not very fluent in python but I thought ...
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2answers
2k views

How to change the vertex style for editing?

When I use drag feature, then the circles on the polygon edge has the same style. For example, this OpenLayers site. I need to change it, I mean they need to be a different color. What is their ...
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3answers
968 views

Remove Holes Existing Within a Single Polygon for a specific area in Qgis

I have a shapefile that consists of a single polygon. I have gaps within the polygon that needs to be eliminated, but only the ones that are less than 200m2. I tried different ways but none of them ...
4
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3answers
3k views

How to add a polygon from PostGIS ST_AsGeoJSON into Leaflet?

I try to use the following function to add polygons to my Leaflet map. function polygon(geojson) { alert(geojson); // alert for testing layer = L.geoJson(geojson); layer.addTo(map); } ...
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4answers
4k views

Remove Polygon Islands

I'm really stumped with the problem. I have a polygon layer with no intersects or holes and I need to remove some 'islands', as defined by attributes of a certain size within the layer. It's a hard ...
4
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2answers
3k views

Is there an easier way to edit polygons in ArcMap?

I am updating woodlot polygons in ArcMap 10. Instead of editing individual verticies, is there a way to edit that is more like drawing part of a new shape (say if the woodlot has expanded only on one ...
4
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3answers
732 views

How to draw a polygon given a distance and bearing in QGIS

Apologies if this question has been asked before I'm not come across it. I want to draw a polygon given a length and a bearing, basically a square with lenght 1m. I cant seem to manage it with the ...