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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4
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1answer
476 views

Clip polygon and retain data

I have these two polygons: library(sp); library(rgeos); library(maptools) coords1 <- matrix(c(-1.841960, -1.823464, -1.838623, -1.841960, 55.663696, 55.659178, 55.650841, ...
4
votes
1answer
1k views

How do I split polygons that cross the dateline?

I have a dataset of country borders which I obtained from: http://thematicmapping.org/downloads/world_borders.php/ I have that dataset in both shp and SQL, but I'll put out there that I don't feel ...
4
votes
1answer
2k views

GDAL - creating vector from raster

[SOLVED] Good day! I'm looking at either gdal_contour or gdal_polygonize.py to create a vector layer file from a raster file. I can create the vector file using either method, but it's upside down ...
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 ...
4
votes
1answer
34 views

Identifying a cluster of polygons based on attributes

I'm trying to identify a cluster of contiguous parcels that, when combined, add up to at least a given size and, when combined, have an assessed property value less than a given $ amount. I have a ...
4
votes
1answer
51 views

How to find the distance from a point to a polygon, via another point, in R

I am trying to calculate the distances between a central point, and the edge of a polygon, along straight lines drawn between the central point and another set of points (where necessary extended ...
4
votes
1answer
728 views

MongoDB: Search for polygons which have a certain location

Good day :). I am trying to implement a search feature on MongoDB using Mongoose.js , the short version of which is this: I tag locations on a map as polygons. and give them names. Then when an user ...
4
votes
0answers
96 views

Reducing Polygons [closed]

I am merging several data sources into one final answer via a fishnet. My problem is I have landcoverage with multiple attributes unioned to a fishnet. Now I want to eliminate the smaller polygons ...
3
votes
3answers
524 views

Sorting polygons by latitude?

We have a set of polygons which we would like to sort and number according to their latitude. This will make it easier for local authorities to relate to the numbers of the objects. I have looked ...
3
votes
2answers
3k views

How can I split a multi-part polygon into single polygons?

i want to split a multipart polygon which consists of several polygons into single polygons so I can delete each polygon without deleting them all at one time. I am using ArcGIS 10.
3
votes
2answers
3k views

How to edit Shapefile Attributes?

How might I go about exporting a polygon shapefile (e.g. CSV) so that attributes (not geometry) are editable by others, and importing it with the changed attributes (of which there are several columns ...
3
votes
4answers
515 views

Is there a way of auto_increment for the ID column in QGIS

I'm creating a fictive map and so I need to create lots of points, lines and for sure polygons. Later on I export my data as geojson. But before that I aways have to go and give every element an ...
3
votes
3answers
803 views

How to clean up a polygon by removing vertices and lines within?

After merging a set of shapefiles I've ended up with polygons that have vertices and lines within them. Is there a simple tool to remove these vertices and clean the polygon in ArcMap 10.2? I realise ...
3
votes
1answer
4k views

How do I rotate the polygon about an anchor point using python script?

I know there would be no tool in arcpy module as such but mignt have in third party modules. I however tried taking the vertices of the polygon and moving using the below formula. but did not get the ...
3
votes
3answers
133 views

ArcGIS - possible to set the drawing order of polygon features [duplicate]

I have a table with polygons that I wish to display in a map. I would like the smaller polygons to appear on top of larger polygons. Is there a way to set the drawing order such that the larger ...
3
votes
2answers
7k views

How can I display this polygon in Google Maps, properly

NOTE: this question is sorta like a follow-on question to this original GIS Question I asked. In that question, the main suggestion was that I was trying to show two polys. Now, I'm asking about a ...
3
votes
3answers
167 views

Using SVG from Wikipedia to fill polygon?

I'm trying to use the flag of each region in Italy to fill each region's polygon. I have downloaded the shapefile of Administrative areas for Italy from diva-gis and am now attempting to fill each of ...
3
votes
2answers
448 views

Overlaying polygon filled with solid colour with diagonal lines in QGIS

I'm making a vegetation survey map using the UK phase 1 survey colour codes. The code for marshy grassland, for example, is orange overlain with purple diagonal lines. For the moment I've created ...
3
votes
2answers
2k views

How to change the vertex style for editing?

When I use drag feature, then the circles on the polygon edge has the same style. For example, this OpenLayers site. I need to change it, I mean they need to be a different color. What is their ...
3
votes
2answers
643 views

How to select polygon features that have their centers outside of another polygon feature class

Since I only have Incorporated area feature class, how can I select census blocks that are in unincorporated area? Or not within any incorporated areas? Thank you. John
3
votes
2answers
1k views

Generate non-overlapping shapes from a buffer

I have a collection of points, and I need to generate shapes around these points. Let's assume that these points are locations of offices and that the shapes are the 'area of responsibility' around ...
3
votes
2answers
994 views

Merge geojson polygons with WGS84 coordinate

I have a Geojson file with some adjacent polygons and I want to merge them into one. I know it's a recurrent question but I can't find information for polygons with latitude and longitude coordinates ...
3
votes
1answer
115 views

Is there an alternative to the Integrate tool that will not change one of the inputs

I have two polygon layers, and would like to snap the outlines of one of them (colored poly's) to the other (grey) without changing the grey in anyway (so Integrate seems out). It should only snap if ...
3
votes
1answer
1k views

How can I get my Qgis area calculations in metres rather than degrees? My shapefiles are projected using WGS 1984 UTM fuseau 35 Sud

I am using Qgis 1.7.4 to calculate the area of polygons. My shapefiles have been projected using the coordinate system WGS 1984 UTM fuseau 35 Sud, but my area calculations are still displayed in ...
3
votes
1answer
131 views

How do I save a polygon once I have created it in editor?

I am attempting to create a new polygon. I go to ArcCatolog>New>Shapefile and make sure Feature type is set to polygon. I create the polygon and if I click save edits or stop editing, it disappears. ...
3
votes
2answers
230 views

Can I convert the sharp edges of a polygon easily to round edges?

I use the python module "shapely" to make Polygons (like below). Can I convert the sharp edges of a polygon easily to round edges? Such that when I have unified some polygons I could issue a command ...
3
votes
1answer
144 views

Tornado Data Points: Linking 2 Points in QGIS on the Same Row

So I've got these tornado .csv files that have two latitude & longitude entries with the left-most in the table being the beginning point and the right-most being the ending point of the tornado, ...
3
votes
3answers
2k views

How to add a polygon from PostGIS ST_AsGeoJSON into Leaflet?

I try to use the following function to add polygons to my Leaflet map. function polygon(geojson) { alert(geojson); // alert for testing layer = L.geoJson(geojson); layer.addTo(map); } ...
3
votes
2answers
153 views

How to automatically calculate maximum cell values contained within polygons?

I've got a dataset made up of a large range of polygons (about 70 or so) which represent structures. I also have raster layers which detail a flood depth across an area. The floods depth raster has a ...
3
votes
1answer
100 views

Using arcpy to find geometry within another feature

In Arcpy, I would like to start with a point and then using its geometry method to find out if it is inside my polygon feature (Urban Areas) deeper than the buffer distance. This is a follow up to ...
3
votes
1answer
429 views

PostGIS - when I add a polygon, delete overlapping areas in other layers

I'm starting to work with PostGIS and I'd like to solve the following problem: In my database, I have multiple land use class layers, for example: "residential", "industrial", "commercial". The ...
3
votes
4answers
2k views

Clip a raster using a shapefile into multiple rasters?

I have a raster file representing a large area and a shapefile of 30 polygons representing watersheds. I would like to clip the raster with the shapefile to create 30 rasters representing each ...
3
votes
3answers
265 views

Is there Shape Metrics Toolbox or equivalent for ArcGIS 10?

I need to compute the geometric properties (e.g. contiguity index, dispersion index etc.) of a series of polygons and I would like to use the Shape Metrics Toolbox. I am using ArcGis 10 and the ...
3
votes
2answers
831 views

How to filter out multipart polygons and then buffer?

I've written a small script trying to accomplish the task described in the question title. It basically looks like: in_fc = '...' # Some shapefile goes here # Get the fields (column names) of the ...
3
votes
1answer
4k views

How can GeoJson polygons be colored programmatically using OpenLayers?

I'm experimenting with dynamically setting the color values of a geojson polygon. In my geojson file, there is an attribute for each polygon called pop_den. I am trying to update the fillcolor of the ...
3
votes
3answers
4k views

Polygon to Raster Tool Problem

I am trying to create a raster data set from county level polygon data for the US. I have successfully created one raster from a dataset, but when attempting another, it does not work. I am ...
3
votes
2answers
2k views

How to perform spatial queries on polygons in mongodb?

I will build a GIS system based on polygons, not just points. I wanted to use mongodb or postgis. how do this in mongodb? Query A - get the center of a polygon Query B - distance between two ...
3
votes
3answers
561 views

Selecting polygons with a minimum internal straight line value - ArcGIS 10

I have a map of polygons representing forest stands. I am trying to sort through them to find those polygons that have a minimum internal distance of 200 m in a straight line (my field sampling will ...
3
votes
2answers
2k views

How to subtract Geometry Point Polygons in OpenLayers?

I have two json arrays, one for background polygon and one for other polygon. And from them, I got two polygon layers. backgroundLayer = new OpenLayers.Layer.Vector("Background Layer", {styleMap: ...
3
votes
2answers
3k views

Measure the area of a polygon resulting from the intersection of two other polygons?

How can I measure the area of a polygon resulting from the intersection of two other polygons? If I use the measure tool or open the attribute table for the resulting polygon, it shows me the areas of ...
3
votes
2answers
4k 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 ...
3
votes
2answers
175 views

Creating polygons from line segments using PostgreSQL and PostGIS

Is there a PostGIS function that creates polygons from multiple line segments? I want to convert the pictured thirteen lines to four polygons. All lines belong to the table "boundary" (gid, geom). ...
3
votes
2answers
252 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 ...
3
votes
1answer
362 views

Displaying adjacent polygon lines beside each other instead of overlapping

I would like to display adjacent polygons with the line work beside each other, not one on top of the other for that shared boundary. I do not want to edit the polygon boundaries - only want to ...
3
votes
2answers
391 views

Remove Holes Existing Within a Single Polygon for a specific area in Qgis

I have a shapefile that consists of a single polygon. I have gaps within the polygon that needs to be eliminated, but only the ones that are less than 200m2. I tried different ways but none of them ...
3
votes
1answer
176 views

Highest DEM pixel in polygon

I'm working with QGIS and have a big DEM raster layer with height information and a vector layer with many polygons, representing 1 x 1 degree tiles. Now I want to find for every polygon the highest ...
3
votes
1answer
101 views

Find small polygons inside big polygons

I'm trying without success to find a solution for problem in ArcGIS and this is the reason that I'm sending this message. I have one polygon shapefile with postal codes for South Africa (no Gap, no ...
3
votes
2answers
240 views

UK area boundaries

I'm working on a web project that requires polygons and lat long coordinates for the boundares of towns, citys, countys and postcodes. Does anyone know where i can obtain this data? i know rightmove ...
3
votes
1answer
316 views

Postgis identify points on the polygon border

I have points geom in gid,pt_geom and polygon geom in gid,pl_geom. Some of the points are inside polygon and some are outside polygon, others are on the polygon boundary. Is there any way to ...
3
votes
1answer
70 views

How many polygons under a point (ArcGIS solution preferred)

Opposite of Point in Poly. How many polygons underneath a point. I have a point layer with many points. I have a polygon layer with many polygons. I need to add an attribute to the points that ...