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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3
votes
1answer
163 views

Polygon to Raster is taking longer in script than in arcmap

I have a large dataset that I am working with. Basically I have a table with 900,000 records that I join to a geodatabase feature layer, then convert that to a raster. This process takes a total of ...
6
votes
1answer
77 views

Is there a way to select only a certain polygon for editing?

I have a spatialite data base with 4300 polygons contained within. I wish to be able to edit the polygons but once i have highlighted the Polygon from the attributes table i find it hard to edit the ...
1
vote
0answers
57 views

Avoid rounding of coordinates in pyQgis

If I get the coordinates of a polygon in qgis by x = geom.asPolygon() It rounds off the coordinate from i.e. -27,200,334.86 to -2.72003e+07 How can I avoid that?
1
vote
0answers
96 views

Is segment of polyline contained in polygon

I am pretty new to arcpy and am slowly learning all its functions. I have a scenario where I am traversing a polyline. I get a start point and an end point on the polyline and form a segment with ...
5
votes
3answers
2k views

OpenStreetMap Neighborhood Boundaries

Is it possible to download neighborhood boundaries from OpenStreetMap? I see on maps that they often indicate neighborhood names; is there a way to retrieve their coordinates and boundary polygon ...
9
votes
4answers
6k views

using shapely: translating between Polygons and MultiPolygons

[EDIT: the solution to this was simply to use OGR to read shapefiles. See geographika's example.] In an ESRI shapefile, there is no distinction between Polygons and MultiPolygons. Furthermore, there ...
14
votes
2answers
1k views

Creating Thiessen (Voronoi) polygons using lines (rather than points) as the input features?

I have a set of line features inside a particular polygonal boundary. For each line, I'd like to generate a polygon inside which every possible point is closer to the given line than to any other line ...
5
votes
2answers
650 views

How to combine data from overlapping polygons?

Here's what I'm working with: Shape file of the current 32 Congressional districts for all states Shape file of the tract boundaries for Texas A DBF format table of Hispanic counts and proportions ...
5
votes
2answers
299 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 ...
1
vote
3answers
2k views

How to auto fill or delete sliver polygons without losing precision?

I am developing some boundaries in which precision holds the key value. Using ArcGIS 9.3 I am converting lines to polygons using the "feature to polygon" tool. The lines are accurate but I find ...
10
votes
2answers
4k views

How to check Topology in QGIS?

I have two Shapefiles with Polygons ( City and Forerst) Is there a Plugin who is able check the topology (QGIS)? Like "Knots do not overlap" or something like that? I dont want that they overlap. ...
4
votes
5answers
698 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 ...
1
vote
1answer
655 views

arcpy points in polygon check

I have a list of points and a list of polygons both in a separate shape files. I am trying to write a ArcPy script to loop through the points, and then the polygons respectively and tell me when a ...
4
votes
4answers
2k 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 ...
2
votes
2answers
947 views

How to create a multipart polygon?

I have two polygons that consist of two separate polygons/lines in QGIS). How can I make this into a multipart polygon, which consists of 1 line in QGIS?
9
votes
1answer
378 views

Compare spatial cluster/agglomeration patterns for polygon data

I have agricultural data in form of polygons which I would like to test for spatial clusterings/spatial agglomerations. All in all I have about 40 variables which I can aggregate and standardize in ...
11
votes
3answers
3k views

How to merge two Polygons in OpenLayers?

I have two polygons. polygon1 = new OpenLayers.Feature.Vector(new OpenLayers.Geometry.Polygon([linearRing1])) polygon2 = new OpenLayers.Feature.Vector(new OpenLayers.Geometry.Polygon([linearRing2])) ...
2
votes
1answer
3k views

How do i calculate line segment lengths within a polygon?

I have a layer with line segments and a layer of polygons (in this case, buffers around points). I need to create a new field for each polygon that contains the total length of all line segments ...
0
votes
1answer
595 views

Geojson multipolygon doesn't work with Leaflet bindPopup?

I have polygon and multipolygon data in Geojson format and when I try to bind popup for polygon, it works perfectly, and when I try to bind it for multipolygon, it doesn't work. Is that some Leaflet ...
1
vote
0answers
31 views

Suggestions for vector format for polygons

I am using two polygon tables in postgis (A and B ). I need to make a vector file that incorporates information of the overlapped polygons B intersecting each polygon on (A). I can make a single ...
1
vote
0answers
62 views

When digitizing, objects are not saved well

I've some problems with digitizing. If I draw a line or a polygon, the line or polygon is saved in the attribute list, but not visible and its location is not saved either (when I zoom to the object ...
0
votes
1answer
2k views

Calculate maximum and minimum elevation for a polygon layer from a DEM [duplicate]

I have a polygon layer and would like to know the min and max elevation within each polygon. My elevation layer is a digital elevation model. I'm not quite sure how to extract that information. I am ...
0
votes
3answers
5k views

Understanding the polygon handler function in Openlayers

Using openlayers, I want to be able to draw one polygon on a map. After one polygon is drawn, I want an event to fire that stops any more from being drawn until a button is pressed. My current code ...
0
votes
0answers
101 views

Where can I get polygons for the Municipalities of Puerto Rico?

I'd like to find GeoJSON files to draw the polygons of municipalities of Puerto Rico. It might be nice get the Nokia Map (or any reasonable publicly available map) of the same regions and overlay ...
3
votes
1answer
887 views

Merging multipolygon data into a polygon

I have a MultiPolygon representation of some shapes in POSTGIS, I am trying to convert them to Polygon data. I tried, st_geometryn(r.geom, 1) but that didnt work because the way polygons are ...
2
votes
1answer
1k views

find polygon corner coordinates

I am trying to get the coordinates of each node of the polygon I create. I would like the attribute table to display the name of the polygon (ex. address) and then the coordinates of the nodes (ex. ...
6
votes
1answer
316 views

Efficiently identifying overlapping polygons with Python

I'm parsing the NOAA severe weather alert feed and using it as a datasource for a weather alerting system. In the feed, I occasionally find a polygon entry for an alert. Unfortunately, counties that ...
1
vote
2answers
429 views

Dissolve polygons - group to others with touching corners

I am working with some data that shows land management. There are many places where corners "touch". I would like to dissolve my dataset so that features are grouped (dissolved) with those that they ...
1
vote
0answers
53 views

Add regular points to each polygon in QGIS [duplicate]

Possible Duplicate: assign and move centroids to their polygons I'm trying to find out a method to define a unique ID based on specific coordinates for each polygon of a shp. The problem is ...
5
votes
1answer
642 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 ...
4
votes
3answers
964 views

Python OGR: convert a point geometry into polygon

I'm writing a routine for creating the convex hull envelop around shapefiles of islands. I could read the data, extract polygons vertices into a geometry and then compute the convex hull. Now I need ...
0
votes
2answers
483 views

Adding values to Fishnet Grid?

I have developed a fishnet grid for my study area. I have various datasets for the area and want to allocate a value (from one of the pre-determined datasets) to each polygon within the Fishnet. ...
6
votes
2answers
244 views

Breaking apart a polygon layer by unique values, creating many new layers

I have a large dataset of habitat information that I need to calculate distances from animal locations to the closest polygon of each habitat type. The way to do this, that I understand, would be to ...
6
votes
1answer
286 views

Can you permanently set the polygon/polyline segment length?

I'm trying to create a several hundred polygons in ArcGIS 10, each of which may have up to several hundred vertices. For consistency sake I would like each line segment in these polygons to be of a ...
3
votes
0answers
101 views

Create perimeter from given area [closed]

I need to develop a web-based application to manage areas inside a bigger area. I already have the initial perimeter, and it has irregular borders like that: . I will need to tell the app to ...
1
vote
3answers
492 views

How to create one KML per polygon (from one Shapefile)?

I have a shapefile containing hundreds of polygons. I need to create a kml of each of the polygon. Is there any way that I may not have to deal each polygon individually and my polygon file may give ...
7
votes
2answers
2k views

How to create a heat map or density map from stacked polygons in ArcMap 10

I have a polygon shape file that has many overlapping features. Each feature represents an area used by polar bears. So some of the polygons overlap and some don't, and there are separate clusters of ...
6
votes
2answers
129 views

summing up over an area based on a distance related function

Through a field study, we learned that the density of a bird species in the forest was related to the distance to forest edge: ln(density) = 1.89*(distance to edge) + 0.34 Now, for any forest ...
3
votes
3answers
359 views

How do I sort polygons by their latitude?

We have a set of polygons which we would like to sort and number according to their latitude. This will make it easier for local authorities to relate to the numbers of the objects. I have looked ...
1
vote
4answers
3k views

Sum of areas in all each polygon layer?

I've got several layers/feature classes in an ArcMap 10 project. Thanks to everyone's help, I'm able to get the areas for the polygons contained within each layer. By opening the attribute tables ...
11
votes
3answers
2k views

Optimizing a nearest neighbor calculation using PostGIS

I'm using PostGIS to calculate the nearest neighbors of polygons. What I want to calculate is the minimum distance from each polygon, to the nearest polygon. Thus far I have got great help from Mike ...
1
vote
0answers
443 views

How to clip the contour map with the polygon using R software?

Hi I am wondering how can I create the contour lines from the discrete x, y and z dataset and then add the shapefile to cut the contour lines by polygon. I want to clip the contour map by the shape ...
5
votes
3answers
2k views

How to interpolate into polygons?

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 ...
4
votes
3answers
301 views

How to subset X number of features from Shape file in QGIS

I'm looking for a means to take a rather large Shape file and split it out into separate, smaller shapefiles based on number of features. So for example, if I have a file with 1 million features, ...
5
votes
2answers
537 views

How to achieve an “inner glow” effect on polygons drawn using the Google Maps v3 javascript API?

Is it possible to produce an "inner glow" effect on polygons drawn using the Google Map v3 javascript API? If not possible using the vanilla Google Maps API, is there a 3rd party tool that can do it? ...
0
votes
3answers
338 views

Calculate 'Rectangle' Coordinates Given 2 Points and width [closed]

I want to create a rectangular polygon using two points as guides. So let's say a journey starts in Egypt and ends in London, my polygon should have 4 points: 10 miles further from London than Egypt ...
3
votes
1answer
360 views

Qgis analysis on polygon

I have a data table mapped and the table also contains further information of interest, beyond the lat/long of the specific data points. I want to be able to draw a polygon and then simply have a ...
2
votes
1answer
96 views

What is the PostGIS function for retrieving buildings by road side?

I want to get information of buildings by the road side only. Assuming that the building table has multi-polygon geometry and the road table has multi-linestring geometry, what would be a pgSQL Query ...
2
votes
1answer
366 views

How to remove a hole from a polygon in OpenLayers?

Is it possible to remove a hole from a polygon by using OpenLayers? How can I do so?
6
votes
1answer
368 views

Generalize large polygon-file

I have a large polygone file with landuse information (6 classes). Its vectorised from a raster classification so the polygons are all angular. Any of my tries to generalize with v.generalize (sneaks, ...