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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6
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0answers
175 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 ...
5
votes
0answers
393 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
votes
0answers
63 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
votes
0answers
139 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
votes
0answers
301 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
67 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
votes
0answers
47 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
votes
0answers
53 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
votes
0answers
66 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
98 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
votes
0answers
188 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
votes
0answers
120 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
236 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
votes
0answers
37 views

Polygon Layer Cleaning with QGIS

I have a little situation with my data. I have vectorized a raster layer, and now I have some issues with the geometries, as you can see in the picture. Most of errors I have are like this one. ...
2
votes
0answers
36 views

R Spatial: Trouble with disjointed polygon that has self-intersections

I have a shapefile which represents the areas of a city which have higher risks of flooding than others. This is a spatial polygon object however the polygon is disjoint and not connected. I also have ...
2
votes
0answers
27 views

Error ET Geowizard Clean Polygon() takes no arguments (3 given)

I want to clean polygon feature classes with ET Geowizards (clean polygon) because I cannot find any tool within ArcMap (ArcInfo) that does the same. I have really small gaps within the polygons (but ...
2
votes
0answers
33 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
74 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
votes
0answers
77 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
73 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
87 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
votes
0answers
100 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
votes
0answers
34 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
votes
0answers
49 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
54 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
votes
0answers
54 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
votes
0answers
141 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
votes
0answers
84 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
votes
0answers
231 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
331 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
138 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
108 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
161 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
580 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
793 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
196 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
85 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
18 views

QGIS - Label polygon with different projections

I have a polygon layer projected in an UTM. In properties I checked 'show all labels for this layer'. Does anyone know why the label does not show until zoom 15:1 in QGIS with CRS-4326, while in ...
1
vote
0answers
21 views

Inflating the boundaries created with convex hull

I have a set of lan and lat points and have plotterd a convex hull for them using QGIS. A polygon is created along the set of points and plotting them on the MAP. Now I am trying to inflate the size ...
1
vote
0answers
21 views

merge polygons of single feature QGIS

I am new to QGIS and have done some research on this topic before posting but not sure I found an answer. I have one feature that has multiple polygons (islands of a nation). In reality, there is ...
1
vote
0answers
42 views

Is it better to work with non-contiguous or contiguous polygons?

I would like to find width-height of a non-contiguous polygon in order to draw paths within it. My question: Is it better to use a bounding box (contiguous polygon) and then clip keeping my real area ...
1
vote
0answers
30 views

Calculate Sum on One Field Within Several Different Point Feature Classes?

I have several point feature classes (eg: the location of mall, liquor stores, etc), that I need to get the count of within a specified city district. Basically, I want to great a modelbuilder model ...
1
vote
0answers
28 views

Merge zip code based polygons to create sales territories

I have access the full data set of the KML file shown here: http://www.maptechnica.com/downloads/samples/mt_2014a_kml_us_zcta5_sample.tar.gz Here's what it basically looks like: ...
1
vote
0answers
18 views

Select a polygon which is just partly member of another polygon with its area of the other polygon

I need to generate random points within geometries, which works quite good, but there are some small errors. Take the picture below. There are some greenish and redish Polygons(?!) which do not have ...
1
vote
0answers
14 views

combine multiple geojsons

I have several geojsons which contain polygons. But the polygons are reaching over other geojsons. When I import them into lets say Qgis, the polygons, which are distributed among several geojsons are ...
1
vote
0answers
26 views

QGIS polygon - filling a polygon gap

I do not use Python, I'm afraid. I need to fill in a polygon gap for this map of Scotland. Here is the gap: How do I fill in this gap? I have already tried drawing another polygon inside the gap ...
1
vote
0answers
21 views

texture fill doesn't display in ArcScene

My texture fill doesn't display properly in ArcScene but it does in ArcMap. What am I doing wrong? Help! ArcMap: ArcScene: The same texture fill has been selected in both ArcMap and ArcScene. ...
1
vote
0answers
30 views

CartoCSS: labels along inside of polygon boundary

I'm using CartoCSS to render maps that include large polygons (like national parks). At higher zoom levels I want labels along the inside of the polygon boundaries, like in OpenStreetMap: I ...