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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1answer
120 views

r - increase speed of crop, mask, & extract raster by many polygons

I'm extracting the area and percent cover of different land use types from a raster based on several thousand polygon boundaries. I've found that the extract function works much faster if I iterate ...
4
votes
2answers
3k views

How to find polygons within polygon using ArcGIS Desktop?

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 ...
1
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1answer
55 views

postgis calculate distance between point & polygon/circle

By basic requirement is to find the nearby fences to a particular point(user lat long alt) within a N meters. I have list of polygon/circle in DB with 900913 srid ...
2
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1answer
238 views

Why is field calculator returning NULL for $x and $y in line and polygon layers?

I am trying to include XY coordinates in the attribute tables of several of my vector files; they are line and polygon files. I have tried two methods; first I used $x and $y in the field calculator ...
8
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2answers
4k views

Converting point sets to polygon boundaries

I'm trying to convert sets of points to their respective polygon boundaries. I think this is something like a Voronoi diagram or Convex Hull, but not quite. I'm sure there's a technical term for it, ...
8
votes
5answers
7k views

How do I convert a Polygon into a single or all Points?

I want to convert polygons into points. I know how it's done in ArcGis and I think this may sound trivial but it's a serious issue :/. I'll appreciate any hints :)
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1answer
197 views

The best way to convert points to polygons using ArcObjects

I have a set of points from GPS I want to convert them to polygons..I have two approaches to do this.1- convert points to polygon..I do this with below code: private IPolygon ...
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1answer
65 views

Convert polygon to point with QGIS [duplicate]

I work with QGIS and I tried to convert polygon into point. I need points all over the perimeter of the polygon. I saw several answers like: Problems converting polygon to point but I didn't see an ...
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1answer
22 views

Calculate raster mode with r.mode - problem with decimals

I am working with a raster file that represents the percentage of vinyards by commune (e.g., municipality) in a region in France. The statistics were calculated for each commune based on surveys from ...
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0answers
5 views

Clip Multipatch Feature class with Polygon Feature Clas

i have city_gml data with 3D buildings lod2. I now want to extract the buildings which intersect with a polygon feature class and create a new multipatch feature class. How can I do that? Thanks in ...
4
votes
1answer
600 views

How to split a polygon using R

I have an irregular polygon which is a spatial object. I want to divide it into multiple polygons (say, n=25) with equal height. To show how I want to divide it, I've plotted grids on the ...
1
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1answer
137 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 ...
2
votes
1answer
67 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
50 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, ...
0
votes
0answers
25 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 ...
2
votes
2answers
250 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
97 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 ...
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1answer
46 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?
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1answer
82 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 ...
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0answers
83 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
137 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
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0answers
78 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
23k 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
168 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
298 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
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0answers
18 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 ...
3
votes
2answers
90 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 ...
1
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1answer
53 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
491 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
72 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
47 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
27 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
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1answer
32 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 ...
2
votes
0answers
84 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
92 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
270 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
35 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
154 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
22 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. ...
1
vote
0answers
30 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
20 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
42 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
44 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
946 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
33 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
92 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
69 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 ...