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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34 views

area weighted average for overlapping polygons [duplicate]

Possible Duplicate: How to use NASS county level crop data to estimate crop acreage in hydrologic regions? It seems like an easy problem but I don't know how to go about it. I have two ...
5
votes
1answer
1k views

Dissolving specific polygons inside SearchCursor with Python in Arcmap

I have a layer with catchment polygons. For those that are smaller than a certain size, I want to merge with an adjoining polygon (namely the one downstream). In the attribute table I have a GridID, ...
12
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5answers
4k views

Get Raster Values from a Polygon Overlay in Opensource GIS Solutions

I have two layers. A polygon-shape-layer with many tiles and a raster-layer containing CORINE 2006 land cover with many categories in a colourmap. I want to obtain for each polygon in the shapelayer a ...
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0answers
798 views

How to handle postgresql/postgis geometry type errors in a function?

I have created the following function in PL/SQL to make a polygon from a set of linestrings: CREATE OR REPLACE FUNCTION _myfunction( _fid integer, _rid integer ) RETURNS VOID AS $$ ...
4
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1answer
652 views

Extracting donut holes as separate layer in QGIS

Does anyone know how I can extract the holes in a polygon layer as a separate layer in Quantum GIS? An example could be a country with a number of lakes cut out of the polygon - I need the lakes. I ...
1
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1answer
425 views

Is it possible to have self intersecting polygons in GML or shapefile?

GIS vector data for example GML or shapefile contains polygonal data. Lets assume, we have polygon A which has self-intersection which means that the edges in this polygon intersect with each other. ...
10
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2answers
3k views

Proper way to rbind SpatialPolygonsDataFrames with identical polygon IDs?

What's the proper R idiom for rbinding SPDFs together when the IDs overlap? Note that here (as is often the case) the IDs are basically meaningless so it's pretty annoying that I can't just make ...
3
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2answers
323 views

Determine density or cover from a raster layer that has been clipped by a polygon

I am a very new GIS user using ArcMap 10. I have a raster layer of tree canopy that I have clipped so that the layer is in a polygon that is a circle with a 2km radius. I have done this for four ...
7
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2answers
2k views

How to sum pixel values within a polygon zone in QGIS?

I have two layers: a raster layer and a vector layer (polygon). I can see the values of the raster pixels but I don't know how to combine them with information from the polygon layer. More ...
2
votes
2answers
1k views

Problem creating polygon features using ArcObjects / ArcGIS 10

I need to create a grid of polygons. Each polygon is rectangle, thus has 4 corners (vertices). When I create polygon features using ArcObjects they seem to have wrong geometry, which results in wrong ...
2
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0answers
162 views

How to dissolve polygons that have been split back into their original polygons?

I had a feature class containging about a thousand polygons.After some processing such as intersecting, dissolving, merging, more intersecting, I ended up with a feature class of about 6000 polys. ...
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1answer
172 views

gdal_rasterize -at function still won't capture covered pixels properly

I'm currently using the gdal_rasterize tool in bash. My code looks like this: gdal_rasterize -l $(basename $file .shp) -burn 1 -a_nodata 0 -te -180 -90 180 90 -tr 0.1 0.01 -at -ot Byte $file ...
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2answers
88 views

How to query points that fall outside their designated regions?

I have a shapefile with 250 points. Each point has a region attribute. In another shapefile I have all the possible regions with their names (it is polyline geometry). Unfortunately the coordinates ...
1
vote
2answers
171 views

information from a shapefile to another shapefile

I am very new to GIS and learning by myself so what I'm about to ask is possibly quite basic. I am using QGIS. I have a shapefile, which categorizes areas (land cover) by numbers (corresponding to ...
1
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0answers
144 views

Creating responsive interaction with tiled maps

I think I may have two conflicting aims but... I need to create responsive Choropleth map very similar to http://leafletjs.com/examples/choropleth.html or ...
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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 ...
6
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0answers
696 views

How to split polygons without ArcView? [closed]

I'm trying to split polygons into equal areas. While fishnet sort of works; the areas I'm trying to split don't touch; they're national parks. Fishnet spans the whole area, not just the polygons in ...
0
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0answers
53 views

Point to Polygon [duplicate]

Possible Duplicate: Create new polygon layers from postcodes latitude & longitude I'm running QGIS 1.8.0 I have a list of points that I need to convert to one polygon. So far I have ...
5
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1answer
73 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 ...
11
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6answers
1k views

How do I make a heat or Choropleth map that uses polygons in QGis?

I've been playing around with the heatmap plugin for QGIS and I am wondering if it is possible to make heatmap with using a similar plugin/tool that uses polygons as well as points? I would like to ...
2
votes
1answer
819 views

Convert shapefile in NAD27 from meters to decimal degrees to match xy data?

I have a shapefile of a boundary (polygon) that has the following projection: NAD_1927_UTM_Zone_11N Projection: Transverse_Mercator False_Easting: 500000.00000000 False_Northing: ...
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1answer
2k views

QGIS, how do you break segments of a polygon, ie break 1 polygon into 2 or more?

I have a polygon but would like it to be in broken up to put into different layers. I can't work out how to do this.
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1answer
345 views

joining a table from zonal statistics as table with a layer, problem with reserved names

I have a raster file (percentage of total forest killed) and a shapefile with polygons (municipalities). I thought as a first step I would like to find out which municipality shows the greatest ...
4
votes
1answer
300 views

Splitting polygons leaves null values

I'm trying to split polygons with overlaping line features, using Split Polygons tool from Topology toolbar. The problem I encounter is that only one from new polygons have old attributes and others ...
4
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1answer
1k views

GDAL - creating vector from raster

[SOLVED] Good day! I'm looking at either gdal_contour or gdal_polygonize.py to create a vector layer file from a raster file. I can create the vector file using either method, but it's upside down ...
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2answers
5k views

How to delete polygon in Openlayers

I would like to delete my polygon in Openlayers after i have drawn it. <html xmlns="http://www.w3.org/1999/xhtml"> <head> <style type="text/css"> html, body, #map { ...
2
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2answers
220 views

How can a style be set on a specific polygon using OpenLayers?

Using a polygon id, I want to highlight a polygon, while the mouse is outside of the map area. I can identify the polygon using the following approach: x = 53; for(i=0; ...
5
votes
0answers
180 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 ...
3
votes
2answers
874 views

How to convert polygon layer to txt files?

Is there any way to convert polygons that do not have coordinates in the attribute table to a txt file with coordinates. I will be using the txt file in a different software (not ArcGIS), so I need ...
3
votes
1answer
3k views

How can GeoJson polygons be colored programmatically using OpenLayers?

I'm experimenting with dynamically setting the color values of a geojson polygon. In my geojson file, there is an attribute for each polygon called pop_den. I am trying to update the fillcolor of the ...
0
votes
1answer
170 views

How to add a label of a point to a polygon

i have several polygons with in each polygon a point with a label (number). I want to add the label in the polygon to the attribute-table of the polygon it belongs to.
6
votes
1answer
1k views

Where can I find a Unesco World Heritage List as boundaries?

I was wondering if anyone knows where to find the UNESCO world heritage list with boundaries? I can extract point data from the json feed for the map on the website http://whc.unesco.org/en/list via ...
3
votes
1answer
854 views

adding polygon to database in openlayers

I want to add a polygon to the database. I used the following code. The problem is that I am to able to save in database. Whatever polygon I draw on map it gets save temporary and as soon as I reload ...
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2answers
1k views

One Polygon Joining to Database with Many matching records

Using ArcMap 10.1. Is this possible to have one polygon and join to a database/excel with many matching records? I would like to have 1 polygon but match to 100 corresponding records in a table. When ...
6
votes
1answer
409 views

How to draw shapes with highest possible decimal accuracy

I am trying to read input of lat and long to draw the shape based on condition.The input is standard array of lat and long with 15 decimal accuracy. I am realizing - I am loosing some decimal accuracy ...
5
votes
1answer
101 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 ...
2
votes
1answer
235 views

How to join attributes of donut polygon to hole polygon in ArcGIS?

First of all I'm completely new to the realm of GIS and ArcGIS. Basically I need a reliable way to determine a donut hole's containing donut for a few hundred thousand polygons (where the donut holes ...
2
votes
1answer
951 views

Geometryutil, simplify polygon, querytask and query fault error

One of the tools in my app is to draw freehand polygons (counties) to show points (companies) in each county. Everything works great but if the user creates an intersecting polygon then I have a ...
2
votes
1answer
133 views

Compiling a list of units that border each other

I have a shapefile of U.S. counties. I am interested in compiling a list of those that border each other. In particular, I am interested in those that border each other but are in different states. ...
2
votes
2answers
546 views

Creating Long & Lat for Polygons

I have a base map image with micro regions, however in the attribute table there is no information regarding the long & lat. Is there a way I can create a long & lat for each micro region? ...
7
votes
1answer
8k views

How do I change the polygon fill color and border color for SpatialPolygons objects?

I have SpatialPolygons or SpatialPolygonsDataFrames which I'd like to plot. How do I change the color using the three plotting systems in R (base graphics, lattice graphics, and ggplot2)? Example ...
8
votes
5answers
2k views

How to get an ocean shapefile from a very detailed land area shapefile?

I am looking for a possibility to "invert" a shapefile. What I want to do is to convert a shapefile with the continents and islands into a shapefile that has water polygons. The existing ocean ...
4
votes
1answer
548 views

Iterate features on SpatialPolygonsDataFrame in R

I have a SpatialPolygonsDataFrame object. Is there way to use apply on this object rather than using a for loop to iterate features in this object?
3
votes
2answers
2k views

How to edit Shapefile Attributes?

How might I go about exporting a polygon shapefile (e.g. CSV) so that attributes (not geometry) are editable by others, and importing it with the changed attributes (of which there are several columns ...
4
votes
1answer
1k 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 ...
6
votes
4answers
327 views

How to avoid holes in polygons from lines?

I am trying to convert a dataset of lines that contains the coast of New Zealand into a big polygon. However using the vector -> geometry tools -> lines to polygon command in Quantum GIS results in a ...
4
votes
1answer
3k views

Arcgis 10: Point layer, polygon line layer, draw points to the nearest polygon point or other nearest line?

I have been using arcGIS for a while now but I often get frustrated with it :( I have version 10.0 arcGIS and I'm have two layers 1) Point data (building locations) 2) a polygon shape file (outline ...
5
votes
1answer
963 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 ...
2
votes
2answers
2k views

Assign unique ID to each polygon

I feel like this should be really simple and I am missing something. All I wish to do is assign a unique ID to each polygon since I have multiple identical FID values. In MS excel I would simply type ...
2
votes
1answer
1k views

Identify duplicate polygons to enable removal after reviewing attributes

I wish to label overlapping polygons so that I can manually locate each overlap then review the attributes of each overlapping polygon and decide which suite of attributes to maintain before ...