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
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262 views

Divide polygon layer by point layer in QGIS?

I have two layers - one polygon layer that is a buffer of a road layer, and one point layer that shows certain locations along that road. What I want to do is to divide/split the polygon layer at the ...
2
votes
0answers
494 views

Clipped raster leaks outside polygons

I am trying to clip a raster (DEM) with a polygon layer in ArcGIS10.1, using Data Management>>Raster>>Clip. Basically the clipped raster has many pixels outside the polygon boundary, mainly for thin ...
2
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0answers
178 views

Matching points in table to polygons

this is my first post to this forum. I hope to start participating actively. I have a table with several records (aprox 200.000), each with its own coordinates. And I need to identify the "Polygon" ...
2
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0answers
123 views

Cannot reselect polygon after modify

I've got various vector layers on a OL map. On one layer I have a few draw controls. If I draw a polygon I can select it (the whole pop-up thing works). This also works for all the other features. ...
2
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0answers
185 views

How to dissolve polygons that have been split back into their original polygons?

I had a feature class containging about a thousand polygons.After some processing such as intersecting, dissolving, merging, more intersecting, I ended up with a feature class of about 6000 polys. ...
2
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0answers
642 views

cant find point/polygon intersect using qgis (windows only)

below i describe the method i am using. i have 2 machines: 1 ubuntu linux, qgis 1.4 - intersection works 2 WIN xp, qgis 1.8 - intersection dows not work hopefully, someone will ...
2
votes
0answers
911 views

How to calculate the area of a polygon considering the relief?

I work in a fire department and i'm mapping all the fires that occur in my area, creating polygons that represent burnt areas. my problem is that the values are not accurate... for instance, arcgis ...
2
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0answers
226 views

Polygons of Land Use Change

I am doing a project where I am digitizing a map of Haiti from the 70s. Through R2V I digitized the lines and then I exported it into ArcGIS 10. I am just interested in the land use change, therefore, ...
2
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0answers
95 views

Determine which points fall within a 3D polygon and export this subset to a flat file

I am working in ArcMap 10 and will have a 3D representation of a zone of transmission. I would like to determine which GPS points fall within this polygon and then export this subset out to a flat ...
1
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42 views

Calculating area of intersection of polygon to another layer in ArcGIS for Desktop?

I am very new to GIS, especially ArcGIS. I am currently using ArcGIS 10.2, and I have 2 layer, namely the purple feature map(this layer is an import from arcgis online, it doesn't seems to be an ...
1
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0answers
37 views

Spplot SpatialPolygonDataFrame and SpatialGridDataFrame

I have to plot in the same graph something like this: Then, I have elements from SpatialPolygonDataFrame class and others elements from SpatialGridDataFrame class. When I try to plot them in the ...
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0answers
29 views

Selecting certain area of polygon according to size in ArcMap?

I have a set of polygons with a certain size (3500 sq meters each for examples). I only need 3000 sq meters of every polygon. Is there an automatic or semi-automatic way to create sub-polygons out of ...
1
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0answers
23 views

Polygon to Raster tool while keeping less than maximum values

I'm trying to convert a very large, detailed polygon to a raster with a coarser resolution in ArcGIS 10.1 using the polygon to raster tool. The value field is a percentage and the cellsize must be the ...
1
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0answers
35 views

create polygons using 2 coordinates

I have a script that creates a text file containing the upper left and lower right coordinates of my geotiff files in the following format. TileName UpperLeftX UpperLeftY LowerLeftx LowerLeftY I ...
1
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0answers
28 views

Point and Polygon Data refusing to display: corrupt data?

I have two sets of shapefiles, one point data and one polygon data. Both were sent as part of a bigger set of data. Neither the point or polygon data will display when loaded into QGIS. The raw data ...
1
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0answers
24 views

Split Polygon Layer by other Polygon layer in QGIS

I know there is a lot of previous posts to this subject, but I simply cannot find the solution I am after in the other posts. I have to following problem: I have two very extensive polygone layers, ...
1
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0answers
29 views

Polygon overlay, calculating changes, in QGIS?

I'm trying to create a relationship file between two vintages of census tracts. (in this case, 2010 and 2013.) Reason being to load ACS (American Community Survey) census data and use weighted means ...
1
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0answers
21 views

Showing polygon in OpenLayers Timeline?

I am trying to use the OpenLayers TimeLine library with a kml file. I used the available example for kml in github, but it shows points instead of polygon. How can I display polygon the TimeLine ...
1
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0answers
24 views

Rotate functions in “Rectangles, Ovals Digitizing” as well as “Advanced Digitizing” distort shape dimensions

I am trying to rotate squares via the rotate tool in the "Rectangles Ovals Digitizing" Plugin in QGIS. The dimensions/proportions of the sides, however, are distorted whenever I do so. Any idea of why ...
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22 views

Create a center node based on both polygon and line shapefile

Sorry for cross posting. I want to develop a node layer from two other layers. One of the layers is a polygon contains a series of zones. Another layer is a line layer of roads. The nodes I want to ...
1
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0answers
17 views

How to show neighboring polygons and polygon in which point exists

We have a table which has polygon related data stored. For finding if a point (long,lat) is within that polygon I am using following query in mysql SET @vasantKunjSectorC = 'polygon((77.161266 ...
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0answers
22 views

Wrong shape type

I am from statistics, and I need to do a fast cartogram. But I am getting this error from ScapeToad: Error processing record (a):160 PolygonHandler.read() - got shape type 1610612760 but was ...
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0answers
56 views

Polygons within Polygons Spatial Analysis

I have a polygon layer of planning applications and I am wondering if anyone can give any advice and or has seen or written a blog post that might point me in the direction of creating relationships ...
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0answers
32 views

How to recognise building type from polygons?

I have a number of building polygons which are extracted from the aerial images, along with their postal address. (The aerial images are not available in my case.) For example, the polygon of a square ...
1
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0answers
32 views

Toggling selected feature when using Node Tool of QGIS?

Does anyone know of a way, when using the Node tool in QGIS to edit a polygon, to choose or toggle which feature (within the same layer) is being selected if they share a boundary? It seems to just ...
1
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0answers
60 views

How to show two layers at the same time in Qgis

I have a question about Qgis layers. I want to see two layers at the same times. one is lines which are boundary lines and the other is polygon which are district. when i was surfing about this ...
1
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51 views

QGIS split line into segments on polygon

Is it possible in QGIS to split a line into segments given which polygon it falls within? I am using 2.8. For example, a line that passes through three polygons will become three separate lines. Each ...
1
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0answers
42 views

Enable editing only one feature in a Polygon Layer using PyQGIS

I was thinking of locking neighboring polygons (parcels) by disabling editing on them, while editing would be possible on the polygon at the center. This means other polygons can also be edited in ...
1
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0answers
27 views

“Impossible to engage a segment in the current layer”

How can I fix this ? My problem is the red "x".
1
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0answers
103 views

PostGIS: intersection of a polygon with 2 rasters

I'm trying to get the intersection of a Polygon with 2 raster layers in PostGIS. The rasters have the same size and pixel size and I'd like to retrieve for the polygon a list of something like that: ...
1
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0answers
64 views

Query to merge simplified polygons according to the map scale-factor

I'm trying to construct a view in PostgreSQL that simplify polygons according to the map scale-factor. Basically I was reading this thread ...
1
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0answers
61 views

XYZ bounding box of a spherical polygon

I'm looking for an algorithm to calculate the 3d bounding box of a spherical polygon - i.e. the min/max X, Y and Z over that part of the surface of a unit sphere. The purpose is to aid fast ...
1
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0answers
33 views

Lines > Polygon artifacts

I am trying to make polygons from a set of boundaries from an SVG file with closed polylines I downloaded off wikipedia. 1) convert SVG to DXF via Inkscape 2) import into QGIS (shows polyline data) ...
1
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0answers
40 views

Shaded KML overlays on OSM tiles in QGIS?

This seems simple - but the solution is escaping me. I have a series of dynamically generated KML files describing simple, shaded polygons, with each polygon having a slightly different (externally ...
1
vote
0answers
52 views

Polygons in Polygons

I have 2 layers, they represent 2 different data. I did a spatial join to see the polygons that fall in the other layer using the match option as identical. Before, i used the intersect as the match ...
1
vote
0answers
44 views

Splitting up a single polygon into many polygons of equal point count

I have point data split into 15 different values and want to split up the (green) polygon into a number of smaller polygons each containing the same number of points so that I can make a chloropleth ...
1
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0answers
271 views

Efficient way of determining polygon intersection with bounding box

I have a set of polygons, and I need to check whether they are intersecting with a given bounding box(rectangle). What I am doing is, I am taking every vertex of polygon and checking whether it's ...
1
vote
0answers
103 views

Convert polygon to raster and give value to null cells

Is there a way to convert polygon features to raster while also populating null cells with a specific value? As in, can I create a raster from a polygon shapefile and have the tool populate all null ...
1
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0answers
110 views

QGIS - Polygon to Lines Tool Incredibly Slow

I am trying to convert a few polygons to polylines so I can save them as a .GPX file. I'm using QGIS 2.8.1 (Wein) on the Mac. It seems to be hanging. I only have a few small polygons (see ...
1
vote
0answers
89 views

Correcting polygon geometry so edges can be reshaped to match that of subsequent layer in ArcGIS for Desktop?

I have two layers; a polygon layer representing maritime boundaries/economic areas of countries in the world and another polygon layer representing all countries but with a detailed coastline. In the ...
1
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0answers
60 views

Progress Bar gets stuck converting Lines to Polygons using QGIS?

I'm trying to convert lines to polygon using QGIS 2.8.1. I use Vector > Geometry Tools > Polygons to Lines. I always get the progress bar stuck on 90%, it can't get to 100%. Could someone ...
1
vote
0answers
58 views

Matching (joining) two slightly incompatible polygon shapefiles

I have two shapefiles that represent two slightly different zonings of the same area (municipality zoning and transport zones), about 3000 polygons each. Several smaller municipalities may form a ...
1
vote
0answers
48 views

Sample points based on underlying polygon attributes

I have a point shapefile and I would like to sample those points (just like the "Sample" tool allows points to sample underlying raster) to receive a table with underlying polygon values (interested ...
1
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0answers
69 views

Why does the transformation bring bad results?

I have this map which has a polygon drawn on it. For the background map I use a WMS via ol.source.TileWMS and the polygon uses a ol.source.Vector object. Normally my view projection is EPSG:31467 but ...
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0answers
505 views

Geofencing: Query if a POINT is within a POLYGON

I am trying to use the following query to search if a point is within a defined POLYGON (aka a geofence I want to define): ...
1
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0answers
52 views

QGIS Partitioning Regions

I have to polygon shapefile maps in QGIS that cover the same area. One with ~90 polygons (call them regions) and the other with about ~800 polygons (call them zones). I want to add a data column in ...
1
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0answers
111 views

Create diagonals in polygon with QGIS or ArcGIS

How is it possible to create the diagonals in/of polygons and to calculate the length of this diagonals afterwards. It's for a lot of polygons so maybe a fast/automatic method would be nice. I ...
1
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0answers
24 views

QGIS - Label polygon with different projections

I have a polygon layer projected in an UTM. In properties I checked 'show all labels for this layer'. Does anyone know why the label does not show until zoom 15:1 in QGIS with CRS-4326, while in ...
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0answers
645 views

Polygon of Voronoi cell using scipy.spatial?

I have points (e.g., lat, lon pairs of cell tower locations) and I need to get the polygon of the Voronoi cells they form. from scipy.spatial import Voronoi tower = [[ 24.686 , 46.7081], [ ...
1
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0answers
123 views

Inflating the boundaries created with convex hull

I have a set of lan and lat points and have plotterd a convex hull for them using QGIS. A polygon is created along the set of points and plotting them on the MAP. Now I am trying to inflate the size ...