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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5
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70 views

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

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 ...
5
votes
0answers
371 views

Grouping analysis of points to divide a polygon into n number of sub-regions

I'm attempting to create n sub-regions from a polygon based on a cluster analysis of a bunch of overlapping raster layers (physical layers, eg: depth, currents, waves). Briefly, I can create a ...
4
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0answers
88 views

Group polygon features to match a set of specifications

I have two different sets of polygon features (398 census tracts and 80 ZIP codes) that each roll up to a larger feature (a US county). Though census tracts are smaller than ZIP codes, they do not ...
4
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0answers
55 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 ...
4
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0answers
132 views

Find and destroy duplicate OSM multipolygon/polygons in TileMill/PostGIS

In OpenStreetMap there are sometimes multipolygons where attributes are present on both the polygon and the multipolygon relation, such as the Grampians National Park: ...
4
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0answers
284 views

How to write a script to square polygon corners?

I'm looking for a script that will square the corners of polygons that are near 90 degrees but not exactly. Near could be dealt with via a variable, for example within 5 degrees of 90 (85 - 95 ...
3
votes
0answers
63 views

Why do each of my buffer-polygons have different areas

I`m using Qgis 2.2 and 2.4 and loaded a wms-map using the coordinate system ERTS89 UTM 32N. I set 8 points (all in on shp-fileand in UTM 32N) on various locations on the map. After that i created a ...
3
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0answers
29 views

What is the area that OGR extracts from the (geometry) shp files for polygons?

The ESRI July 1998 technical documentation for polygon shapefiles at page 10 makes no mention of either area measures or length measures (apart from byte/record-layout matters). Yet OGR enables me to ...
3
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0answers
40 views

Dilating a polygon by a circle sector

I want to dilate a polygon by a circle sector in ArcMap. Because my python skills are not that good to figure out how I can use the R prototype of How to create an oriented buffer using arcpy? . Is ...
3
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0answers
54 views

Geoprocessing tool for finding specific point within polygon

I have a ArcGIS task and cannot find a solution. I try to find a certain point within a polygon (see picture). This example is handmade and I need a geoprocessing solution I point I try to get is ...
3
votes
0answers
93 views

Reshaping polygons while preserving area

I'm looking to manually skew the shapes of areal polygons, but need to ensure their areas are not altered. Is anyone aware of any GIS tools or programming workflows that exist for manually reshaping ...
3
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0answers
181 views

Closest set of points to another set of (predefined) points

I have 10 sets of points which I call templates that I have manually classified from 0 to 10. Each point is a X, Y coordinate in a text file. Each template has 5-8 points. I have new sets of points ...
3
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0answers
118 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 ...
3
votes
0answers
226 views

Area-weighted rasterising of polygon data

I'm looking for any GIS tool to do detailed rasterising of polygons. I've checked GDAL's gdal_rasterize command (and API), and ArcGIS's Polygon to Raster tool, but they only rasterise 1 attribute per ...
3
votes
0answers
59 views

Passing attributes to neighbouring polygons

I have an ecosystem polygon layer that has been updated using a more recent tree cover layer (to remove cleared areas and also to re-align veg boundaries where growth has occured). Where the polygons ...
2
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0answers
9 views

Geoserver : create a rasterized polygon / dynamic fill for polygons with features from database

I decided to post here because I couldn't find any answer to my problems on the internet. So I am using geoserver 2.7-SNAPSHOT, everything is working fine but I need to implement a new function or ...
2
votes
0answers
45 views

How to merge an excel file with a shapefile in r

I am new to mapping in R so my question might look trivial. I want to have a density map of US for number of phone calls for different areas. Each area includes some zip codes. I only have number of ...
2
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0answers
57 views

Merge vector layers to fill gaps in QGIS

I have a zip code map which I added per zip code data too (a regional director for each zipcode), and then dissolved the map based on the director attribute. As you may or may not know, zip codes are ...
2
votes
0answers
51 views

Extracting gridded data from polygon vector layer

So I've spent a few enjoyable (and frustrating) days teaching myself the basics of QGIS and fiddling around to try get some data output I need to drive some calculations. Sadly I'm not having any joy ...
2
votes
0answers
36 views

Dividing a polygon into two OpenLayers

I'm using OpenLayers to draw a polygon to my users. I want the ability to implement through a line, split the polygon into two, with the cutoff line that the user drew. Does anyone know if this is ...
2
votes
0answers
70 views

Using R to subtract the polygon area of one shp file from another

I'm looking to produce a map from two separate maps in R. My Maps files are as follows: ftp://ftp.cpc.ncep.noaa.gov/GIS/us_tempprcpfcst/610prcp_20140822.zip #Map1 ...
2
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0answers
73 views

How can I merge adjacent polygons and return all (adjacent and not adjacent) as Multipolygon?

I have a postgres database with administrative boundaries and their geometry. Each of those boundaries have an ident number. What I want to achieve: First I want to select all rows which are ...
2
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0answers
30 views

Polygon parcel division in python

Is there an open source tool or module in python that does parcel division of polygons like in ArcEditor?
2
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0answers
45 views

ArcMap - proportion of polygon in lon/lat grid cells

I have a polygon representing a river basin on a 1 X 1 degree lat/lon grid. I need to create a boundary using the grid cells as the boundary to best represent the outline of the basin. I would like to ...
2
votes
0answers
45 views

CartoCSS: Don't show border between adjacent polygons

In OSM, riverbeds are created as multiple adjacent or even overlapping polygons. When styling these polygons in CartoCSS with a border, the overlapping can be seen: I'd like to hide that line ...
2
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0answers
51 views

Does converting polygon to raster generate more accurate results from the Zonal Statistics in Arcgis 10.2

I have heard the following for Arcgis 9.1 and wonder whether it is still an issue in Arcgis 10.2. If so, should I convert the polygon into raster before dissolve or convert the dissolved polygon ...
2
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0answers
137 views

Joining nearest neighbor small polygons using R

The figure shows a plot of numerous polygons (zoom in) made from a raster file by require(sp) require(raster) pol100 <- rasterToPolygons(r, fun=function(x){x==1}, dissolve=FALSE) There polygon ...
2
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0answers
67 views

Using ST_Affine() and trans_param() functions on vector layer

After reading this post How to georeference a vector layer with control points? I decided to give it a try to move/rotation/scale a polygon using Postgis. I have two polygons, polygon_from and ...
2
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0answers
222 views

Divide polygon layer by point layer in QGIS?

I have two layers - one polygon layer that is a buffer of a road layer, and one point layer that shows certain locations along that road. What I want to do is to divide/split the polygon layer at the ...
2
votes
0answers
303 views

Clipped raster leaks outside polygons

I am trying to clip a raster (DEM) with a polygon layer in ArcGIS10.1, using Data Management>>Raster>>Clip. Basically the clipped raster has many pixels outside the polygon boundary, mainly for thin ...
2
votes
0answers
127 views

Matching points in table to polygons

this is my first post to this forum. I hope to start participating actively. I have a table with several records (aprox 200.000), each with its own coordinates. And I need to identify the "Polygon" ...
2
votes
0answers
103 views

Cannot reselect polygon after modify

I've got various vector layers on a OL map. On one layer I have a few draw controls. If I draw a polygon I can select it (the whole pop-up thing works). This also works for all the other features. ...
2
votes
0answers
157 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. ...
2
votes
0answers
557 views

cant find point/polygon intersect using qgis (windows only)

below i describe the method i am using. i have 2 machines: 1 ubuntu linux, qgis 1.4 - intersection works 2 WIN xp, qgis 1.8 - intersection dows not work hopefully, someone will ...
2
votes
0answers
762 views

How to calculate the area of a polygon considering the relief?

I work in a fire department and i'm mapping all the fires that occur in my area, creating polygons that represent burnt areas. my problem is that the values are not accurate... for instance, arcgis ...
2
votes
0answers
192 views

Polygons of Land Use Change

I am doing a project where I am digitizing a map of Haiti from the 70s. Through R2V I digitized the lines and then I exported it into ArcGIS 10. I am just interested in the land use change, therefore, ...
2
votes
0answers
84 views

Determine which points fall within a 3D polygon and export this subset to a flat file

I am working in ArcMap 10 and will have a 3D representation of a zone of transmission. I would like to determine which GPS points fall within this polygon and then export this subset out to a flat ...
1
vote
0answers
5 views

Trouble in Natural Earth Shapefile “jumps” read using GeoTools

I'm using GeoTools 12.0 to read in Natural Earth data. I'm really happy with the performance, and ease of implementation. But, I'm having trouble reading in very large polygon data. The 110M Ocean ...
1
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0answers
23 views

Determining Euclidean Distance in Polygon using ArcGIS for Desktop?

I would like to ask about how to create an euclidean distance analysis from a polygon shapefile. I got a geology shapefile in which I want to create a "distance from geological boundary" analysis. ...
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0answers
12 views

How to merge DMAs using QGIS — Creating Custom Regions?

What I am trying to do might seem basic, but bear with me as I am just hacking my way through a lot of this space. What i am trying to do: I am trying to create a new .shp file of custom regions. ...
1
vote
0answers
40 views

Invalid join selectivity error in postgis 2.1.3

I have 2 tables, one for points and one for polygons. I want to find points falling within theese polygons, so I quered: select p.id, l.id from points p inner join polys l on st_contains(l.geom, ...
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0answers
35 views

QGIS 2.4.0 doesn't support multiple types of geometry in GML file

I'm testing GML 3.2.1 data according to INSPIRE Data specification (version 3.0). Data for theme Cadastral Parcels shall have both polygon geometry and definition point. When I download data from my ...
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0answers
25 views

How to use GIS data with CGAL?

I read a few posts here at GIS.SE that points to useful algorithms in CGAL. I'd like to test algorithms in CGAL such as medial axis transformation/polygon skeleton extraction, but the examples on the ...
1
vote
0answers
62 views

How to clear areas outside map in R

I succeeded thanks to the eblonde in the disscution (problem with polygon smoothing in R) to smoothing polygons in R. Code: inter1= read.table("c:/inter2.csv", header=TRUE) #add a category ...
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0answers
52 views

Create Polygon with inner polygons from KML or Shapefiles?

I am creating a windows forms application and I want to create a polygon from a KML or Shapefile as a layer on top of a Google Satellite map. Today I am using GMap.NET that got an polygon object but ...
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0answers
129 views

Convert polygon data into extreme lon/lat coordinates using QGIS

I'm very new to QGIS. I have a shape file of census blocks and want to use the data to plot points within each boundary using Google Maps api. I figure the best way to do this is to find the extreme ...
1
vote
0answers
37 views

Joining polygons with same boundaries

Sorry if my question feel stupid but I'm a new QGIS 2.4 user. My shape is composed of 7 polygons which are supposed to be adjacent (ie sharing sharing same nodes). Would like to join the polygons by ...
1
vote
0answers
68 views

spatialpolygons heatmap in R - NAs in grey?

I have a spatial polygon data-frame and I am trying to plot a heatmap via spplot. It's a map of Europe and the values for the heatmap are in a column of the data-frame. Plotting it works fine but I ...
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0answers
67 views

Way to split and create buffer space between polygons in QGIS or ArcMap

After performing a feature extraction of rooftops, some of my buildings have been joined together as one polygon. I want to split these large polygons so that each new division is only covering one ...
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0answers
78 views

Merge overlapping GeoJSON GeometryCollections

I need to merge three overlapping GeoJSON GeometryCollections of Polygon. Ultimately, the end result needs to be a geom type for PostGIS (e.g. MULTIPOLYGON) so I can easily check if particular points ...