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
votes
1answer
56 views

Merge polygons in CartoDB?

I created this map in cartodb: http://cdb.io/1xBj4Xo Now I have to merge some of the districts to a bigger district. Is it possible to do this in Cartodb? Using a SQL query for instance? I can also ...
2
votes
2answers
44 views

Create lines from polygon borders with polygons attributes

I have a shapefile of polygons that border each other perfectly, each with a numerical attriubte. I'd to create a shapefile of lines, where every line is created from the border between two polygons, ...
1
vote
2answers
124 views

How to resample polygon vertices so that they are evenly spaced in Arc 10

I have digitized the outline of many river channels (by both manually picking points and using streaming mode), but now I need the vertices to be evenly spaced (for input to another program). I tried ...
0
votes
0answers
23 views

polygon will not project correctly into project

I have a project that one shapefile( I believe created in arcgis) layer mysteriously quit projecting correctly. I am using Q 2.6.1 On the fly is enabled, coord system set at EPSG:4326 - WGS 84, when ...
1
vote
2answers
44 views

Extracting/Exporting coordinates from polygons (shape) to text?

Is there any well working way to extract the X and Y coordinates of a polygon from shapefile to some sort of text (preferably csv)? The whole process should be somehow done automated through a ...
2
votes
2answers
219 views

Calculate the number of points in a freehand polygon ArcGis Javascript API

I'm drawing a free hand polygon on my map. Now I want to calculate the number of points found in that polygon. I have done this code, which my now is giving me the number of points found in the map ...
2
votes
2answers
85 views

How to mask labels in QGIS using an inverted polygon?

I created a file consists of a raster (snow load) and a vector with municipal boundaries. I added a vector with the contour lines of the snow load. Labels represent the snow load (kN / m2). With the ...
1
vote
1answer
30 views

CartoDB - How do you do a line fill of polygons in CartoDB?

I would like to show overlaping layers with hash marks, is this possible by editing the css in some way?
1
vote
1answer
72 views

How to clear areas outside map in R

I succeeded thanks to the eblonde in the disscution (problem with polygon smoothing in R) to smoothing polygons in R. Code: inter1= read.table("c:/inter2.csv", header=TRUE) #add a category ...
1
vote
0answers
82 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 ...
2
votes
2answers
126 views

Can't transform lines to polygons

I have a similar question to: How to join lines in QGIS for later using "lines to poly"? I have a line shapefile that I wish to transform into a polygon shapefile. After making some ...
7
votes
6answers
3k views

Lines to Polygons

I have failed to find the "name" of the algorithm that would allow one to convert lines to polygons. Since this issues crosses GIS and the fields of computational geometry and computer science. I am ...
1
vote
0answers
72 views

Line features into polygon features

Can any one tell me how to convert line features into polygon features in ArcGIS. I am using ArcGIS 10. I searched the arc toolbox for any tools for this conversion, but I couldn't find any. Please ...
6
votes
4answers
22k 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 ...
2
votes
1answer
166 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 ...
2
votes
1answer
229 views

How to remove columns in a spatial polygon data frame in R?

My spatial polygon data frame (spdf) contains too many columns (variables) and I want to remove most of the columns entirely. I know how to do this with a regular data frame in R, but I am unsure how ...
0
votes
0answers
11 views

Outlining multiple KML objects

I have a KML file (generated from Census data) that outlines several contiguous counties. How do I go about getting KML data to draw a border outlining the combined area of the counties instead. My ...
2
votes
3answers
227 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 ...
3
votes
2answers
74 views

Counting number of points in particular polygon for list of individuals using R?

I have distribution points for a set of individuals and a file of polygons-with matching IDs. What I would like to do is to go through and for each individual find the total number of points and the ...
0
votes
1answer
537 views

How to narrow the result from Nominatim with only cities and countries, no additional areas with the same name?

I'm trying to get WKT or GeoJson polygons of cities and countries from Nominatim (for example, Paris and France). I send a GET request but it returns me several results named "Paris" or "France". How ...
1
vote
1answer
49 views

Cover a polygon with fixed size squares

Can you please advice me of an algorithm (which I can implement in a Java) to cover some polygon (not exact cover) with squares of certain size (aXa squares)? The cover doesn't have to be exact - ...
5
votes
2answers
449 views

Rgeos drops associated values when intersecting polygons

I am trying to intersect two SpatialPolygonsDataFrames and get a SpatialPolygonsDataFrame as the result. Unfortunately, using the gIntersection function from rgeos (which works impressively quickly ...
2
votes
1answer
64 views

Area in KM from Polygon of coordinates

I have polygons from coordinates in (python shapely) that looks like this POLYGON ((24.8085317 46.8512821, 24.7986952 46.8574619, 24.8088238 46.8664741, 24.8155239 46.8576335, 24.8085317 46.8512821)) ...
0
votes
1answer
39 views

Merging polygons which have different coordinate system with map coordinate system?

in order to merge the polygon I go to editor tool and then select merge, however in my case when I want to edit it is giving me this statement" the layers are in a different coordinate system than the ...
0
votes
0answers
24 views

Unit of Geotools' getArea function

I have Polygons with WGS84/EPSG:4326 coordinates (like 13.57933804767844,52.5126298984133) and use the Polygon.getArea function to obtain the area of the polygon. But the result I get is something ...
1
vote
1answer
22 views

Checking if point is within multipolygon using ST_Contains?

Why is this query always returning false? SELECT ST_CONTAINS(the_geom,(select ST_GeomFromText('POINT(26.8715 80.7799)'))) FROM blockgeom Can I not check if a point is within a multipolygon using ...
5
votes
2answers
3k views

Removing sliver polygons in ArcGIS Desktop?

I unioned 2 layers into 1 layer, and it created sliver polygons. I used the elimination tool to merge them with neighboring polygons. As as result, it merges all sliver polygons to only one polygon ...
0
votes
0answers
19 views

How to transform isolines to isopolygons with postgis?

I have a table a postgis table of isolines that's defined like this: CREATE TABLE myisolines ( gid serial NOT NULL, isotime timestamp without timezone, val numeric(10,4), geom ...
2
votes
0answers
79 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 ...
4
votes
1answer
83 views

How to add Attributes to a polygon with arcpy

I have a question about arcpy. I want to create a polygon FeatureClass with attributes. The code below is just test-code that generates some polygons for speed testing. I want to add some additional ...
3
votes
1answer
193 views

Polygon fill colour specified by column R spplot

I am trying to plot a geological map using the spplot function in R. For every unit I already assigned a specific color in the col-column of the SpatialPolygonsDataFrame. Now I would like to plot the ...
0
votes
1answer
31 views

eliminate small polygons of a PNG with gdal_sieve

I want to eliminate polygons wich consist of less than 3550 px in this PNG . I tried using gdal_sieve but there seems to be an error. gdal_sieve -st 3550 E8.png -of PNG E8sieve3550_4.png ERROR 6: ...
6
votes
2answers
1k views

Finding long axis of irregular polygon using ArcGIS Desktop?

I need some help in how to find the long axis of an irregular shaped ellipse using ArcGIS Desktop. I have found the centroid but don't know how to determine the longest distance.
7
votes
1answer
149 views

Suitable algorithms for simplifying isochrone polygons

I'm looking for an algorithm for simplifying isochrones which were generated using OSM data. These are generally characterised as having lots of small "holes" mostly due to missing OSM data but also ...
1
vote
0answers
13 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. ...
0
votes
0answers
16 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 ...
1
vote
1answer
16 views

Trouble in Natural Earth Shapefile “jumps” read using GeoTools

I'm using GeoTools 12.0 to read in Natural Earth data. I'm really happy with the performance, and ease of implementation. But, I'm having trouble reading in very large polygon data. The 110M Ocean ...
1
vote
0answers
36 views

Join/convert points to polygons

(I am using QGIS 2.6 Brighton) I have 2 shps, one points and another one polygons. I need to make them one. Is there a way to join them or convert the points to polygons? Vonoroi doesnt work for me ...
2
votes
1answer
37 views

How can I resize polygon features in ArcGIS based on an attribute value?

I have a polygon dataset representing all the municipalities within a certain county. I am wondering if there is a way to resize each feature in the dataset based on an attribute value. Obviously, ...
2
votes
2answers
917 views

Openlayers Vector Layer Polygons not displaying properly with OSM

I have an Openlayers map displaying Acetate tiles in OSM, and I'm drawing polygon regions on a vector layer to represent the countries of the world. This works fine for the most part, however, there ...
2
votes
0answers
23 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
1answer
78 views

neighborhood boundaries for Saudi Arabia

I currently have set of coordinates (lat,lon) that I would like to associate with neighborhoods or districts in Saudi Arabia. Therefore,I might be looking for neighborhood boundaries (polygons ...
1
vote
1answer
63 views

Split lines by polygons in QGIS 2.4

I have a river network (lines) and a shp with states (polygon). I would like to split the lines at the state boundaries --> split lines by polygon boundaries. Is there a geoprocessing tool to do ...
0
votes
1answer
33 views

gdal_polygonize ignores some polygons

I want to polygonize this PNG. I try gdal_polygonize pic.png -f "GeoJSON" polygonized.geojson but I get only 11 polygons instead of more than 20. What is the cause or how can I fix it?
7
votes
7answers
2k views

Intersection algorithm that correctly handles the 180° meridian and poles?

Is there a well known intersection algorithm that correctly handles 180 meridian and poles? For example, let's say we have a list of latitude and longitude values that represent Antarctica. Let's ...
2
votes
1answer
225 views

Convex Quadrilateral Polygons subdivision in equal parts using Python / OGR

Consider an irregular polygon (P) which has four vertices. I would like to subdivide P into smaller polygons as shown here http://i.stack.imgur.com/4SKhB.jpg In the old days I was using ArcGIS 9.3 ...
2
votes
2answers
66 views

What's the best way to determine if a point is within a certain distance of a GEOJSON polygon?

What's the best way to determine if a point is within a certain distance of a GEOJSON polygon? Should one use TurfJS buffer method (https://github.com/Turfjs/turf-buffer#turf-buffer)? Can one perform ...
0
votes
1answer
38 views

How to select all polygons where neighbor vertex points are below a distance threshold in arcmap

I have a shapefile with over 100k polygons (some of them have holes in them but apart from that they are simple polygons - no multipart). I want to loop through all of these polygons and select only ...
1
vote
2answers
42 views

Moving polygons to points

I have a polygon shapefile that corresponds to a point shapefile in the same projection. I need to move the polygons so that the vertices line up with the points. Right now they are about 3 feet off ...
0
votes
1answer
50 views

How to combine multiple zipcode polygons into one polygon

In CartoDB, we have a table of chapters that make up a national organization. Each chapter record has a polygon that defines the geographical area that the chapter covers. The area a chapter covers ...