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.

learn more… | top users | synonyms

1
vote
1answer
100 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
85 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
159 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
86 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
25k 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
176 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
406 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
24 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
107 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
vote
1answer
64 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
537 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
81 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
62 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
45 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
49 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
87 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
115 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
374 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
40 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
2k 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
164 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
31 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
42 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
24 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
46 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
68 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
0answers
40 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
111 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
75 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
45 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
231 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
161 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
54 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
58 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
69 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 ...
4
votes
2answers
334 views

What methods exist for geohash of polygon?

GeoHash is an excellent method to code the latitude and longitude of a point into a string. It's concise, due to the use of numbers + letters, and the precision can be tuned adding characters at the ...
7
votes
0answers
254 views

Group polygon features to match a set of specifications

I have two different sets of polygon features (398 census tracts and 80 ZIP codes) that each roll up to a larger feature (a US county). Though census tracts are smaller than ZIP codes, they do not ...
10
votes
3answers
304 views

From polygon to continuous measure of diversity?

First of all; I have tried to find a similar question, without success. Maybe it's because I'm quite new to GIS and I don't really know what exactly I'm looking for. If someone points me to a similar ...
1
vote
1answer
125 views

Need to quickly know (CLI) whether point lies inside polygon

in my app I am parsing an XML from the web which gives me such coordinate info: I am able to use my app to get a pair of float values like 14.871381 and 50.065968. I do not want any complicate ...
6
votes
1answer
2k 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 ...
0
votes
0answers
170 views

Leaflet vs Openlayers vs Geoserver for overlapping polygons application

I have 3 layers of vector polygons(about 80 polygons - 1MB geojson each but I haven't simplified any yet) displaying school territories (kindergardens, primary and secondary education) and I want to ...
5
votes
0answers
96 views

Split polygon by area using ArcGIS for Desktop (or QGIS)? [duplicate]

I'm interested to split a larger, irregular polygon into smaller ones. I know the area of the resulting polygon, and I know that the line I want to split it by should be parallel to one of the sides ...
1
vote
0answers
22 views

How to delete lines that do not overlap a polygon? [duplicate]

I'am new to QGIS and I run into a problem. I have two shapefiles, one with line data and one with polygon data. I would like to remove all the lines that do not overlap the polygon. So remove all ...
0
votes
1answer
39 views

Want to intersect a polygon of a certain elevation with a tin surface

so I want to generate a flood plain for a river in ArcMap. Basically this means that I want to create polygons with certain elevations above the drainage point elevation (870 m). For instance I would ...
1
vote
0answers
57 views

Determining Euclidean Distance in Polygon using ArcGIS for Desktop?

I would like to ask about how to create an euclidean distance analysis from a polygon shapefile. I got a geology shapefile in which I want to create a "distance from geological boundary" analysis. ...
1
vote
1answer
64 views

QGIS how to align existing polygon borders

I'm looking for a method to align the borders of two overlapping and already existing polygon layers. I'm aware of the node tool and its tolerance snapping option, but the area I'm working with is too ...
2
votes
1answer
84 views

Why are a polygon's vertices jumbled after importing KML into MySQL?

This is original KML : <Polygon><outerBoundaryIs><LinearRing><coordinates>104.700355,-3.056064 104.632127,-3.103623 104.608924,-3.103169 104.570166,-3.102411 ...