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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2
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1answer
772 views

Conversion of raster features to polylines: skeletonization?

I would like to identify linear features, such as roads and rivers, on raster maps and convert them to a linear vector features (i.e. polylines). I typically use R as my primary GIS, and have posed ...
2
votes
1answer
2k views

merging 2 polygon adjacent to each other using R

I have several shp files which are the components (or tiles) of a map, I have joint all these tiles together to have a large shp file. Then I realized some of the polygon is now splitted into 2 ...
1
vote
1answer
560 views

Aggregate Data between Polygons

I have data at the ZIP3 level and I need to join it to a state file. I also need the data within the zip3 file to be averaged, but for some reason when I use the join tools, i'm not getting the ...
4
votes
2answers
2k views

Is there an easier way to edit polygons in ArcMap?

I am updating woodlot polygons in ArcMap 10. Instead of editing individual verticies, is there a way to edit that is more like drawing part of a new shape (say if the woodlot has expanded only on one ...
2
votes
1answer
2k views

How to get the radius of a “circle” in Openlayers

How do you get the radius of a circle in openlayers? I have searched quite a bit and cannot find any resource for this. please help. Here is my code but I want the radius or circumference of the ...
3
votes
1answer
242 views

Best Method for Validating polygons?

I would like to assess the spatial accuracy of a load of polygon shapefiles which are supposed to show air quality for a bunch of countries. Firstly I want to assess whether each shapefile has a ...
2
votes
1answer
615 views

How do I subdivide and edit polygons preserving topology?

I'm using QGIS. I have a layer made up of many adjacent polygons - let's call them "countries". I currently use the Atlas plugin to export each "country" polygon to a .png file. I want to further ...
9
votes
4answers
22k views

How to split a polygon into multiple equal-width polygons in ArcMap 10?

I am adding parking spaces into a parking lot, and I need them to be exactly the same shape and not overlap each other or have spaces between. In ArcMap 9.3, there was an editing task that allowed you ...
0
votes
1answer
566 views

CenterPoint of Polygon in ArcEngine .Net 10

I am currently trying to get the center point of a polygon. In GIS, i can see the "x" mark in the center of the polygon, but I do not know how to get it from the IPolygon object. I tried getting the ...
0
votes
1answer
2k views

How to change events in the Oncomplete Drag function in Openlayers

below is code that works for Openlayers drag function: drag = new OpenLayers.Control.DragFeature(polygonLayer, { autoActivate: true, onComplete: function() {alert('Are you sure this is the ...
1
vote
1answer
325 views

Highlighting and exporting raster layer based on vector polygon

I am a Quantum GIS beginner. I have a set of adjacent polygons in a vector layer that is overlaid on a raster layer of OS StreetView OpenData. I want to be able to select each of these polygons and ...
0
votes
2answers
10k views

Openlayers How would i get a hover label over my polygon

make a hover/mouseover label for a polygon in Openlayers? I made a map with draw, delete and drag polygon function. Now I need to make a hover mouseover for this. How to get a hover label for ...
1
vote
1answer
3k views

Openlayers get coordinates of a circle vector after draw

I have made a openlayers map. I have made two features on the map. Navigate DRAW POLYGON I have made 40 sides to my polygon which turns out to be a circle. After I have drawn my circle I want to ...
2
votes
1answer
494 views

SUM Area irregular polygons per grid cell

I have a shapefile of irregular polygons and a GRID (both as raster and polygon grid). How can I count the AREA SUM of irregular polygons per grid cell? Can use ArcGIS, QGIS or R. (Application: ...
6
votes
1answer
5k views

How to convert a String to OpenLayers.Geometry.Polygon using javascript?

First let me say that I'm using Javascript, jQuery, Java, GeoServer, OpenLayers and PostGIS. Using java class ResultSet I return this String: POLYGON((516000 2135000,515039.264020162 ...
6
votes
4answers
21k views

How to create polygons from lines?

I am trying to create polygons from a line layer of lots and concessions (large blocks of land in rural areas). The lines are mainly grid style as they intersect mostly at right angles. I need to ...
4
votes
1answer
4k views

Create point in intersections of two layers

I have two layers. One of them is 'Road_line' and another one is 'forest_shape'. I want to create a point layer that has points in intersection of that layers. I couldn't find any tools for it. Could ...
5
votes
3answers
385 views

Selecting polygons by number of sides

I'm using ArcGIS 10 to build some figures for a journal article. One is a figure of an unstructured finite element mesh of triangles spanning the western Atlantic Ocean. I exported this mesh from ...
2
votes
1answer
1k views

Transform polygon to equivalent circle, QGis

I have a polygon and I'd like to find the radius of an equivalent circle from a particular point within the polygon. The polygon would have a large (infinite) number of points evenly distributed ...
6
votes
4answers
696 views

Exporting polygon features to individual image pngs

I have a shapefile with a few thousand polygons, ArcGIS [9.3] (and even PostGIS). I would like to export each of those polygons into its own thumbnail image file without any real context. What is the ...
13
votes
2answers
2k views

How can I fix my complex Polygons so they show correctly in Google Maps?

Problem: I'm trying to find a way to fix some broken polygon shapes and I'm not sure how I can do this. Details: I've got a number of polygons which I basically imported from TIGERLINES a while ...
5
votes
1answer
1k views

How to calculate the size of a particular area below a buffer in QGIS

I have a point shapefile of villages where data was collected in Northern Kenya. I created a buffer around those villages. The second vector layer contains polygons defining areas according to ...
2
votes
2answers
2k views

How to automate point-in-polygon queries in ArcView?

Layer1 = point shapefile (multiple points, geocoded) Layer2 = polygon (1 attribute; (1,2,3...)) I want a non-gis person to be able input a single address and be told the attribute of the polygon ...
3
votes
1answer
367 views

Splitting raster pixels by a polygon's edge?

I have a a polygon shapefile of different regions, and a raster grid of precip data. I want to take the polygon and add up all the raster precip data in each zone. I could use zonal statistics to do ...
5
votes
1answer
2k views

How can I transform a polygon to a linestring in QGIS?

I have a polygon, imported from a shapefile in QGIS. I would like transform it to a linestring instead so I can save it as a GPX file later. How can I transform a polygon to a linestring in QGIS?
4
votes
1answer
2k views

How to select and copy a group of polygons in QGIS?

I'm new to QGIS. I opened a few shapefiles that cover Europe. Now I want to select a smaller area and if possible copy the polygons in this area so I can work with a smaller set. How should I do this ...
5
votes
1answer
1k views

How to persist a polygon to SQL Server database and vice versa?

How do I extract all the points from a Polygon drawn in ArcMAP and then persist that data into a SQLServer database table containing a geometry column and then when I've got the data persisted read ...
5
votes
1answer
2k views

Count number of unique raster pixels in polygon using ArcMap?

I have a polygon shapefile and I want to generate a table of a count for each pixel value in each polygon. My main goal is to find out what pixel is most abundant in each polygon. I am using ArcMap ...
3
votes
3answers
2k views

How to select the vertices from a polygon?

I am writing some VBA code to extract vertices from a polygon. I would like to ask, how to select the vertices from a polygon ? Regards Gary
7
votes
1answer
946 views

Should I split MultiPolygons into Polygons?

In the system I'm implementing I have a table T1 with an associated geometry. Most of the geometries are a set of n polygons, with 10 < n < 100. At the moment in the table T1 I have a geometry ...
4
votes
1answer
2k views

Convert shapefile lines to a polygon in GRASS

I have a shapefile of a map that is the outline of a number of islands. I would like to convert the lines into polygons (ie all islands filled in) using GRASS. I searched on how to do this with GRASS ...
6
votes
2answers
1k views

Finding parcel polygon features with frontage on multiple streets

The Department of Public Works would like to know how many properties in the city have a sidewalk at both the front and back. To get at this, I'm looking for a method to find parcels with frontage on ...
4
votes
1answer
1k views

Create overlapping polygons from contour lines

Working in ArcGIS 10, I have a set of contour lines representing density of commercial square footage, and I have a set of points representing local maxima for each peak of the dataset. For each ...
6
votes
1answer
1k views

How to eliminate gaps in the ArcGIS union operation?

I have a layer that has nested polygons in them. I want to aggregate the polygons. I do this using the Union function. I use the "No Gaps" option when I perform the union. However, when I overlay ...
5
votes
3answers
1k views

Why doesn't the split tool return any records in the attribute table?

I've been trying to split a large land use shapefile using a set of study area polygons as the split feature, but when the function finally finishes running (the land use dataset is quite large), all ...
4
votes
2answers
3k views

Arcgis: How to find polygons within a polygon?

I am new to GIS and ArcGIS. I have a problem I need to solve: I have a set of polygons, some of which enclose other polygons. They are lake polygons, and within lake polygons, are smaller island ...
5
votes
3answers
1k views

How can I display with OpenLayers the geometry returned from a ST_Buffer in POSTGIS?

Im using PostGIS, GeoServer and OpenLayers, and the thing is that i want to display the geometry result from a query like this: SELECT ST_Buffer(ST_GeomFromText('POINT(100 100)'), 500); To perform ...
5
votes
1answer
1k views

How to create a polygon from other polygon boundaries?

I want to write an algorithm that creates a polygon inside a hole made by a set of other polygons. It's something like a flood fill and it's like the "boundary" tool in Autocad. The image shows an ...
4
votes
2answers
4k views

ArcObjects - Finding the intersection of a polyline and polygon?

I have a polyline and polygon. The polyline will intersect the polygon at two or fewer points. I would like to get these intersection points as X and Y values. EDIT: Here is a quick code sample using ...
3
votes
1answer
276 views

Polygon Shared Boundaries in GML

Last week I was told on a phone conference that GML supports shared boundaries in Polygon's. I have been unable to find any documenatation to substantiate the claim. Here is the situation: I have a ...
8
votes
2answers
756 views

Resize polygon along one axis

Using the following example I'm able to resize by scale and origin. polygonFeature.geometry.resize(scale, origin); vectorLayer.redraw(); But does anyone have any suggestions or sample code ...
4
votes
3answers
7k views

How can I calculate the center point inside a polygon in ArcGIS 9.3?

I'm using the JavaScript API 1.6 on ArcGIS 9.3. I have a polygon geometry in an ArcGIS map, and I'm trying to find a way to get the point that lies in the exact center of the geometry. What is the ...
3
votes
4answers
355 views

Creating Polys and Displaying geo points within. ( Where to start? ) [closed]

Hey all, I'm somewhat of a newb when it comes to creating mapping solutions. I've stayed on a pretty high level playing with openlayers and pulling data from various webservices. The first part of ...
15
votes
4answers
756 views

Why do valid polygons repeat the same start and end point?

In the GIS world, for most modern formats and Standards (e.g., Shapefiles, WKB/WKT, GML, KML, etc.), valid polygons need to have closed linear rings, which is a linestring of coordinates where the ...
4
votes
5answers
22k views

How to connect points with a polyline in ArcMap 10?

I have a layer containing a few hundred points representing a survey track. The points are laid out in chronological order in the corresponding attribute table. How can I have ArcMap 10 automatically ...
6
votes
2answers
2k views

Openlayers geometry: how to convert area from degrees to square kilometres?

I get a multypolygon from my web service and want to calculate the area of that polygon. I was trying to use this piece of code: var poly = new OpenLayers.Geometry.MultiPolygon(poligon); var area = ...
3
votes
2answers
3k views

Label *beside* polygons in ArcMap 10?

I try to add labels to polygons in ArcMap 10 based on a field in the corresponding attribute table. However, the labels always appear inside the polygon, and I can't find an option that lets me put ...
1
vote
0answers
95 views

Getting started with storing LoST and GML searching

I am working on a logging and search database application. The application will receive event records containing XML LoST values (RFC5222 Location-To-Service-Translation). These records will be ...
10
votes
3answers
814 views

Polygons from Polylines in either ArcView or FOSS

I have 20,000 polylines in a .gdb that represent about 5,000 building footprints. Some of the building footprints have pretty substantial gaps (image below). I would like to snap the polylines closed ...
3
votes
3answers
5k views

How to create a polygon buffer from a line?

I have connected a series of points into a line in ArcMap 10 with the Points to Line tool in the ArcToolbox. The line is, of course, in its own layer, and I added a 5 meter buffer around the line. It ...