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.
6
votes
3answers
588 views
How best to fix a non-noded intersection problem in PostGIS?
I'm using a PL/R function and PostGIS to generate voronoi polygons around a set of points. The function that I am using is defined here. When I use this function on a particular dataset I get the ...
9
votes
1answer
131 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 ...
9
votes
3answers
2k 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
297 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
127 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
26 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
51 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
197 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
3k 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 ...
1
vote
2answers
308 views
Openlayers remove previously drawn polygon on starting to draw next one
Objective:
At any point of time there SHOULD only be zero/one polygon(s) on a vector layer with a polygon control. I need the previous polygon to be removed as soon as user starts drawing the first ...
2
votes
1answer
100 views
Tearing in ggmap (R) after using spTransform and random point generation using splancs
I am using R and the package ggmap to try and generate some random points within the city limits of Chapel Hill, NC. I have downloaded the shapefile for the town of Chapel Hill from the Orange County ...
0
votes
0answers
27 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 ...
0
votes
0answers
30 views
Error which are logged in console window
I have Polygon feature layer consisting of 2 lacks of feature but i am displaying few features depending on filter which we apply dynamically.if server returning 1 thousand records also then also it ...
3
votes
1answer
143 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
125 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. ...
0
votes
0answers
115 views
Editing a MultiPolygon in Geo Django admin Google Maps vs Open Street Maps
I have a website where we currently edit MultiPolygonFields in the Django admin using GoogleMaps V2 rather than the default OSM Open Street Maps layer.
V2 is getting shut down soon in May 2013 and ...
6
votes
1answer
171 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
90 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 ...
0
votes
0answers
63 views
ARCGIS Polygone manipulation : Splitting if area>=5KM or merge if area<=0.5KM
I'm just facing a wall. I don't know if even possible to complete the process with modeling. I may need to work with python script which I'm not used to it.
In this state, I got a buffer created from ...
1
vote
0answers
45 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
137 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 ...
3
votes
3answers
287 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
107 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
135 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
154 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 ...
0
votes
0answers
87 views
How to create curved polygons using OpenLayers and MapServer? Any Alternatives?
I've created a website that uses OpenLayers, MapServer and a SQL2008R2 database. Part of the website allows users to draw polygons to overlay a map of the UK. Ideally, these polygons need to have ...
4
votes
1answer
259 views
What is the best way to connect spatial data with attributes in Excel table?
I have many attributes which are stored in an Excel table. They refer to USA counties. I need to somehow connect those attributes to polygons in some format (don't know which is the best) and ...
3
votes
0answers
57 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
266 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
487 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
68 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
149 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
2k 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 ...
10
votes
3answers
1k 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
172 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
687 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
83 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
291 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? ...
3
votes
0answers
159 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 ...
0
votes
3answers
213 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
223 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
76 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 ...
0
votes
0answers
81 views
Regional statistics from a dataset (point inside a polygon aka region)
I am relatively new to GIS and I am trying to do some geographical analysis on same data I've collected. The dataset I have consists essentially in a file with the following format:
...
2
votes
1answer
116 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
195 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, ...
3
votes
0answers
98 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 ...
2
votes
1answer
105 views
Obtain normalized raster average per polygon?
I have a raster that contains percentages of total forest killed plus a polygon layer that defines different zones.
My goal is to find a good statistical representative that describes the forest ...
7
votes
3answers
307 views
How to sum up values of neighbouring polygons?
I hope that you can help me with the following problem: I have a vector (polygon) layer. I would like to add an attribute to the layer that - for every polygon - sums the values of a specific field of ...
10
votes
3answers
210 views
How to improve drawn shapes in Quantum-GIS?
I have a polygon-shape in qgis-1.7.0 and want to fix overlays and gaps between the edges of adjacent polygons. See image below.
Is there any automated way to do this in quantum-gis? Or any other ...
3
votes
1answer
321 views
How to enable “snapping” in Quantum-GIS while drawing polygons?
I tried to draw polygons in qgis-1.7.0 and I somehow can't find or failed to find the "snapping" option. I'm used to ArcGIS-10.0 where you have some snapping options, like placing points of polygons ...
