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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4
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1answer
113 views

What is the best format to encode polygons such as lakes?

I am looking for a standard format to encode polygons, such as lakes, in one file that is easy to create and common so that others can use it in different GIS systems. Every file will contain data on ...
3
votes
3answers
188 views

ArcGis 10 - create polygons as % of original

Could someone help me with the following? I have a polygon shapefile and need to create new polygons, within the originals, as % of original area. I used buffer by field (Field= new area as %) but the ...
1
vote
1answer
142 views

Get Features from OpenLayers Layer.Vector not working

polygon_layer = new OpenLayers.Layer.Vector("Polygone", { projection : projLonLat, strategies : [ new OpenLayers.Strategy.Fixed() ], protocol : new ...
3
votes
4answers
733 views

How to import polygons from OSM to QGIS?

I am trying to import Polygons from OSM to QGIS 2.0, but so far I have no idea how to do that. E. g.: Kisterseg auf Tatabanya in HU: http://www.openstreetmap.org/?relation=1027806 Is there any fast ...
1
vote
1answer
66 views

Merge Two Polygons Using Editor merge in arcGis

i want to create a ArcEngine function using .net that allow to do the same thing like (see picture): select 2 polygons click merge Is there somebody who can help please!! Sincerely
2
votes
2answers
136 views

Convert polygons to KML file

I have a set of polygons out of which I want to make a KML file, my table schema is as follows : CREATE TABLE [dbo].[utilitygeo]( [ID] [int] NOT NULL, [PolygonID] [varchar](8000) NULL, ...
0
votes
1answer
61 views

Openlayers selection

Is it possible to select a polygon from a predefined Lat & Lon programmatically? eg location point: x='1234' y='5678' intersects polygon '1234', therefore SELECT POLYGON '1234' So far I have ...
1
vote
1answer
172 views

Intersection of multi-polygons in postgis

How can I get the intersection of 3 multi-polygons in postgis? I have three geometry collection and I want a fourth with the result of intersection of the other three. ...
1
vote
1answer
74 views

What is the best public geoservice for getting data about buildings?

What is the best public geoservice for getting data about buildings, which is free? Or maybe it's better to ask "does exist such a public service?" I want to add some 3d polygons to my 3d plane, ...
0
votes
0answers
40 views

Polygon shading is darker in certain areas

When drawing in qgis i am encountering an error when drawing large polygons snapped to multiple points. Polygons that have this shading in certain areas are not displaying correctly in other ...
1
vote
0answers
70 views

Free cartographic texture resources

I've been trying without success to find free textures to use in TileMill. I'm looking for fairly simple, abstract textures, like a dotted pattern (to indicate national parks). Are there any well ...
0
votes
1answer
241 views

QGIS: CSV point grid to polygon - not raster

I have a CSV file with various data in 1 degree wide by 0.5 degree high rectangles, for which I have the N,S,E,W, & centroid lat/longs, i.e. every bit of spatial data required. I'm trying to ...
4
votes
2answers
764 views

Dissolve polygons in QGIS (GEOS) with tolerance

I have a polygon vector layer representing the area inundated in a flood. The layer has been produced in a such a way that some of the areas are composed of multiple smaller touching polygons (see ...
1
vote
2answers
105 views

how to set width & height of a polygon in QGIS

I can't setting width and height of a polygon How to do that in QGIS? Thank you
1
vote
2answers
315 views

How many interior and exterior rings can a polygon have in a standard ArcGIS shapefile?

working with GDAL/OGR library and studying these two slides about geometries and vector data in the OGR library: slide 1 slide 2 I found that a polygon can have an exterior ring and lots of ...
0
votes
0answers
87 views

How to access vertices in a polygon layer using ogr library with c++

up to now I have tried these classes in order to extract the vertices of polygons: OGRPolygon : It doesn't have any method to get number of vertices, start point and end point. OGRLineString : ...
1
vote
2answers
155 views

Integrate grid and polygon of municipalities keeping the biggest municipality per cell with QGIS (or another)

I have a 9x9 grid and a polygon of municipalities of an extensive area of Brazil. My goal is to have a field indicating the biggest municipality per grid cell. I've been trying with intercept without ...
2
votes
0answers
87 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: ...
1
vote
0answers
60 views

level of spatial aggregation of polygons

I am looking for a method that allows me to obtain the spatial aggregation of polygons for each cell of a grid with 10kmx10km resolution. In each cell (10kmx10km), I want to be able to consider that ...
1
vote
0answers
75 views

Divide polygon based on points for even distribution

If I have a point layer, how can I create a polygon that includes all of the points and divide that polygon into n sections in which each section contains an equal number of points? Preferably in ...
2
votes
2answers
179 views

Finding points along a path

I am unsure of the best approach to this problem. I can think of some ways of doing it which I will list below but I am looking for the best and most efficient way of doing this. Problem Given a ...
1
vote
1answer
112 views

Split polygon into lines

I have a polygon layer which looks like this . I used the QGIS multiparts to singleparts tool and also polygon to lines. In both cases i got this type of result . I want to extract polygon into ...
1
vote
0answers
58 views

Convert polygon feature to line feature

I have a polygon shape-file i need to extract the line segments where the polygon features intersect each other and also the segment where they don't. Can we automate this process or can scripting ...
4
votes
1answer
121 views

Select by location of doughnut hole polygon

I have vectorized the Corine Land class raster and want to select certain classes that are "inside" other classes. How can I select the polygons circled in blue? All the select by location options ...
1
vote
1answer
46 views

How to get a centroid of a closed line in MYSQL

I have a table that contains only closed lines (lines where endpoint is the same as startpoint). I would need to find a centroid for those lines. How would I be able to achieve it? It does not ...
0
votes
1answer
48 views

How to get average polygon? [duplicate]

Is there a way to get an average polygon of unioned stack of polygons in ArcGIS 10.0? I would like to get an average polygon that would be centroid (but polygon) of whole stack of polygons.
0
votes
1answer
44 views

represent multiple geometry as single feature

There is a school. it is on two disjoint areas, one is primary wing and other is secondary. I need to make single feature from the two areas such that, there is only one column in gis table, i.e. only ...
1
vote
1answer
177 views

Polygon to raster without losing any polygons

I'm trying to convert polygons to raster. But the output raster dataset doesn't have polygons which went into as input data. I need all the date in the attribute to follow with to the raster dataset ...
1
vote
1answer
92 views

Extract polyline of border between differing polygons

I have a shape file with polygons with an associated variable that can take different values. I would like to extract the borders between polygons of differing value (red and blue) as a polyline (dark ...
1
vote
1answer
226 views

Failed to convert polygon to raster

I have two steps here. First select layer by attributes. Second convert polygon to raster. It failed when it goes to second step and kept giving me error 999999: Error executing function. I pasted my ...
0
votes
1answer
74 views

How to send polygon data to wms?

I use OpenLayers and GeoServer. I can read kml file format from OpenLayers. And I want to edit this polygon in kml. So I want polygon data(polygon circle and center coordinate etc..) to GeoServer.
2
votes
2answers
257 views

Iterating polygons on a SpatialPolygonsDataFrame in R with readWKT

I have fetched some data (39 objects) from my PostGIS database and converted this data into a matrix: rs <- dbSendQuery(con, "SELECT ST_AsText(polygon_accumulation) AS ShapeWKT from ...
3
votes
1answer
182 views

Merging partially overlapping polygons into a table in PostGIS

I have a couple of tables (three) with polygons (landuse coverage in this case). Within each table, there is no overlap, but between tables there might be a lot of overlap. I would like to combine ...
0
votes
1answer
175 views

How to convert OSM polyline data to polygons?

I just now downloaded OSM data .I am having the data as polylines. I want that polylines as polygons is it possible in Qgis?below I also posted the screen shot of the polyline also.
2
votes
2answers
92 views

Determining closest representation of polygon as collection of points+radii

Have a bit of a tough question, which I realize there may not be an easy solution to. Figured what better place to ask. I'm attempting to transform a polygon into a series of arbitrary points with ...
0
votes
2answers
200 views

ArcGIS 10.1 - Using Polygon Neighbors with dissolved polygons

I've used polygon neighbors to find all neighbors of a polygon layer, which I then use to look up all possible neighbor combinations and dissolve the polygons into all possible combinations of two ...
1
vote
1answer
260 views

identify percentage of raster cells within a polygon

As per the title I want to determine the population inside multiple polygons according to different land use zoning (High Residential, Low Residential, National Parks etc) that's in raster format. ...
0
votes
2answers
330 views

Detecting invalid polygons (self-intersecting or touching)

An invalid polygon can be defined as one that intersects itself, or one where the lines make contact, ie, the two shapes at the top of this picture. Given the XYPoints of a polygon, what logic ...
3
votes
2answers
260 views

How to do a Point to Polygon analysis with multiple variables?

I have a database of almost 10k crimes, which are divided in to 10 categories and plotted on a map I also have a database of 12k addresses, which are also plotted on the map. I aim to perform a ...
0
votes
0answers
68 views

Polygon dynamic grid creation for a shape file

I have used QGIS Vector->ResearchTools-> Vector Grid to create a 1lat x 1 long grid for the landpolygon shape file (from osm). Now, I am interested in creating dynamic grid for the original ...
2
votes
3answers
152 views

How to change 0,360 WKT string to -180,180?

I'm reading POLYGON WKT strings using OpenLayers.Format.WKT().read(). The polygons use 0,360 longitudes but my map is -180,180. When I display the polygons on the map they are displayed outside of the ...
0
votes
1answer
130 views

Polygon grid shape file for landmass

I am interested in generating a polygon grid shape file for the landmass of the world. What I have presently is two tables in postgreSQL. Table 1: Coastal area shapefile ...
1
vote
1answer
47 views

problem in merging adjacent address polygons in qgis

I am having 15 polygon shape files of a sub locality of a city that is having address in their attribute table. I want to merge these polygons based on the address in the attribute table?how can i do ...
0
votes
1answer
158 views

How to count number of stores per company per region?

I have two layers. One point layer and a Polygon layer. It is simple to count the points in the polygon layer by the "points in polygon" function. But I also need some more information of the point ...
3
votes
0answers
76 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 ...
0
votes
0answers
79 views

how to avoid Intersection of polygons via python code

i am using QGIS 1.8 and i can set the check box in Setting\Snapping Options "Snapping and Digitizing " dialog to avoid polygon intersections and enable topological editing but i am looking for a way ...
0
votes
1answer
49 views

Polygons Shrinking and Moving as if CRS Was Suddenly Out of Sync with Project

I long ago set the CRS for a linguistic geography project I'm working on involving Oklahoma data (EPSG:2836 - NAD83(HARN) / Oklahoma North), and I have been closely monitoring that the polygon ...
6
votes
1answer
184 views

Creating an “average” polygon

I found this thread in the old ESRI forums with the same type of problem I am facing today. The solution to the problem is explained in little detail and since I am not an expert, I was wondering if ...
0
votes
1answer
587 views

How do I write a MYSQL spatial query to find all polygons (rectangle) that contain any points in a table?

Something like: SELECT * from polygons WHERE bounds CONTAINS(SELECT geom_point from points) Can someone help me out with the syntax? Bounds will always be a rectangular polygon and everything is in ...
0
votes
1answer
50 views

Converting an Experian (Geoconcept) file to GPS coordinates

I'm working with a file containing Experian data which was used in Geoconcept. The file describes a serie of microzones, that is polygons. Unfortuntely the coordinates system is hard to understand: ...