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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10 views

Join/convert points to polygons [on hold]

(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 ...
1
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0answers
5 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
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0answers
7 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 ...
0
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1answer
37 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 ...
0
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1answer
46 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
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1answer
24 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
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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
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1answer
220 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
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2answers
35 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 ...
3
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1answer
104 views

How to map flood areas from a set of points containing surface and height of water?

I am working on the damages made by the typhoon Haiyan. I use QGIS 2.0 with extensions and toolbox, and MapInfo. I have vectors, rasters of the place. I want to map the flood area along the ...
0
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1answer
25 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 ...
0
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2answers
178 views

Calculating minimum/maximum width for overlay of two polygon strips in ArcGIS or some Opensource GIS

Is there some solution for calculating minimum and maximum width for overlay of two polygon strips? When I clip these strips the result is another strip with variable width about 1 km and 20 km long. ...
1
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2answers
36 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
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1answer
37 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
204 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 ...
3
votes
1answer
109 views

Postgis 2.0 geographic polygon has max longitudinal range

My problem is that I have a load of geographic point data (srid 4326) in a table. A user may do a bounding box search - essentially create a polygon as follows: l_poly geography(Polygon,4326):= ...
0
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0answers
33 views

Raster to Polygon using 13GB DEM [closed]

I need to perform Raster to Polygon with the DEM that is about 13 GB. What software is the best to perform that can handle which software ? I have ArcGIS 10.1 Ecognition Developer 64 QGIS GDAL ENVI ...
4
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0answers
86 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
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3answers
248 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
100 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 ...
0
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2answers
758 views

How to get a list of OSM relations (id numbers) of cities and countries only?

I want to get OSM polygon shapes (GEOJson or WKT) of countries and cities only. I know that it is called a "relation" in OSM and each relation has its own id (New York is 175905, for example). How may ...
6
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1answer
1k 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 ...
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0answers
54 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
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0answers
70 views

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

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 ...
2
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1answer
176 views

Determine when I have crossed state line?

We are currently using the Google Maps API to get route information and total mileage but we would like to determine when we are crossing into a new state. When we return the route information we can ...
1
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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
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1answer
16 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
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0answers
23 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. ...
0
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1answer
87 views

Optimizing ArcPy code to cut polygon?

There is a lot of nested loops and wondering of ways I could speed up this code? Any ideas? Note: This requires ArcMap 10.2 def cut_geometry(to_cut, cutter): """ Cut a feature by a line, ...
0
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1answer
488 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
32 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
60 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 ...
2
votes
1answer
30 views

QGIS: How to merge single polygons to multi part polygons by maximum distances?

I have a polygon layer with a land-use class and ID for every polygon. How can I merge polygons (into multi part polygon) which do not adjoin, but are not further than x meters apart from each other. ...
1
vote
2answers
108 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 ...
2
votes
3answers
225 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 ...
2
votes
0answers
45 views

How to merge an excel file with a shapefile in r

I am new to mapping in R so my question might look trivial. I want to have a density map of US for number of phone calls for different areas. Each area includes some zip codes. I only have number of ...
0
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1answer
35 views

CartoDB - Multipolygon not showing intersections

I'm having an issue with Multipolygons on CartoDB. I have a very simple scenario: A multi polygon row on a table that needs to be displayed on the map. Fact is that when more than two polygons ...
5
votes
1answer
413 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
0answers
51 views

Extracting gridded data from polygon vector layer

So I've spent a few enjoyable (and frustrating) days teaching myself the basics of QGIS and fiddling around to try get some data output I need to drive some calculations. Sadly I'm not having any joy ...
1
vote
1answer
26 views

How to convert Geodatabase to open standards to process it further?

I have a ESRI file in geodatabase format (v9.3). I intend to use this in a non-commercial application. I think I will have to convert it into a open standard since I am confused if ArcGIS online would ...
1
vote
1answer
36 views

Why does one polygon disappear when merging in edit mode?

I want to merge some polygons into one using the merge tool. But when doing so, one of the polygons just disappears (see screenshot 2). Why does this happen? When I use the simplify tool before, it ...
0
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0answers
18 views

GRASS: How to remove several categories from a geometry?

I am totally new to GRASS (and have found it difficult to get into that way of thinking and its terminology). I use grass70 under Ubuntu 14.04. I have the following problem which I have tried to ...
5
votes
1answer
2k views

How to calculate polygon area considering slopes?

I am looking for an accurate algorithm or a service to calculate surface area on earth where points are calculated on the basis of GPS Coordinates. I am using Google Map Api version 3 and are drawing ...
2
votes
2answers
64 views

QGIS calculates main soil type of polygons from another polygon layer

I've been working with qgis for a while but somehow I never fiured this out, so I thought it's time to ask. I have 2 shapefiles. a polygon layer from nearby fields (SHAPE1 (the red outlines)) a ...
0
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1answer
325 views

How to calculate the percentage of distribution in each polygon?

I have binary map for disease suitable area and I want to calculate the percentage using pixel count in each polygon how can I do that? I use zonal histogram and do have frequency for each polygon is ...
2
votes
1answer
24 views

Percentage of a polygon at, or less than, a specific height (supplied by a raster)

I am using QGIS to process some LIDAR data. I need to be able to define the area of a pond with respect to its depth (i.e it is 100m^2 at 32mAOD and 500m^2 at 33mAOD). Is there a way of finding the ...
9
votes
7answers
14k views

Get boundary of raster image as polygon in ArcGIS Desktop?

I have a rectangular raster image in ArcGIS. My question is: how can I produce a polygon which is just the extent of the raster image? That is, I want to have a polygon layer with a single ...
1
vote
1answer
99 views

Smoothly interpolating Polygons from set of coordinates?

I'm still quite new to QGIS and I'm using it to display and analyze my soil data. I have point information on the distribution of the soils in a specific area and I need to create a soil map from ...
3
votes
0answers
63 views

Why do each of my buffer-polygons have different areas

I`m using Qgis 2.2 and 2.4 and loaded a wms-map using the coordinate system ERTS89 UTM 32N. I set 8 points (all in on shp-fileand in UTM 32N) on various locations on the map. After that i created a ...
3
votes
1answer
212 views

digitizing (tolerence) error in line data

I have designed a large number of boundaries. For accuracy, I took lines in patches from different data sets and merged them into one. Now I want to turn them into polygons from lines. I every second ...