The process of producing a polygon feature layer from a raster or from lines.

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17 views

Does CartoDB automatically fill in Polygon data for city/state? How?

I'd like to upload a spreadsheet that has custom city/state information and have CartoDB automatically fill in the polygon data - is this possible? If so, how?
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1answer
47 views

Converting rasters to polygons through cell centers

With arcgis, it is possible to convert a raster image to a polygon representing the boundary of the raster using the Raster To Polygon tool. The output polygon will follow the cell edges of the ...
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1answer
88 views

qgis polygonize error 4 “file does not exist in the file system”

When I try to convert a raster DEM (in asc or geotif format) to polygons I get the error below. ERROR 4: `Y:/GIS/oversvmmelser/tmp/out.tif' does not exist in the file system, and is not recognised ...
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1answer
38 views

QGIS show gdal_polygonized file in EPSG:54004 instead of EPSG:3857

I am polygonizing a TIFF with the gdal_polygonize.py and the resulting Shape is shown in QGIS in the wrong projection - EPSG:54004 instead of EPSG:3857. I have a TIFF in EPSG:3857 and polygonize it ...
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0answers
43 views

Error in polygonising raster data with QGIS on Mac

I'm using QGis Chugiak on a Mac and I'm trying to converting a raster layer in a vector data by: Raster/Conversion/Polygonize. So, I select the layer needed from the drop-down menu, I give a name to ...
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1answer
28 views

Defining areas for inclusion in polygon conversion using ArcGIS for Desktop?

Using ArcGIS 10.2 for Desktop, I am trying to create a polygon shape(s) from a raster image. Is there a way to indicate areas I do not want included in the shape. Similar to a buffer I suppose, but ...
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1answer
34 views

How to crop a vector shapefile according to raster?

I am trying to clip a vector shapefile- points according to a DEM in QGIS. I used GDAL function and polygonized the DEM. Then I ran the Vector-Geoprocessing tools-clip in order to crop the vector data ...
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36 views

Polygonize Missing Polygons

Polygonize is not capturing all of the pixels in an image that has been converted to 0s & 1s. The pics below show -original geotif -geotif recalculated to 0s & 1s -polygonize output As the ...
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51 views

Polygonize only pixel values of 1 from a raster

I have a raster mask that I have created in QGIS (2.2.0) that consist of 0, 1 and nodata values. I would like to end up with a polygon dataset that consist of only the value of one pixels from this ...
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1answer
49 views

How to split Polygons by line grid?

I want to split a polygon by a intersecting line into different parts, exactly like in this post(Qgis - Is there a way to split a polygon layer with a line layer?). I have a vector grid to cut the ...
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1answer
75 views

How to convert boundaries in image to polygons in QGIS

I have an image from a cities districts and their boundaries and I need them as polygons in QGIS. I tried "Raster -> Conversion -> Polygonize (Raster to vector)" as described here, but that ...
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1answer
95 views

How to colour contour lines in .shp file when the lines are not meeting in QGIS?

I am doing bathymetry analysis, where I would like to color the contours one by one in the case land is rising (or sea level going down). There is a comprehensive explanation about coloring contours ...
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59 views

Polygonize a raster using GDAL JAVA bindings - passing raster pixel value to the resulting feature

I have a raster GeoTIFF file with values from 0 to let's say 5. When I run gdal.polygonize (I'm working with JAVA and GDAL bindings to JAVA) on it, I get features with corresponding polygons. The ...
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2answers
317 views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
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2answers
92 views

I have a table with a series of lat/long points - how do I convert them into polygons?

I have an Excel sheet with about 150 points (lat and long in decimal degrees) which belong to about 15 different polygons. The columns I have are FID, NAME (the same between polygons), POINTS (points ...
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0answers
38 views

How to specify a polygon face toward to different lines

I have a parcel layer, a street of city layer, I want to find the parcels at the corner of two different street (mean a house with two face toward to 2 streets) I appreciate your suggestion for ...
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0answers
95 views

Convert a classification image to aggregated polygon in shapefile using gdal/python

My goal is convert a 2D numpy array to shapefile. The matrix results from a classification, so the numbers have a meaning. I solved my problem, but the solution is somehow involuted and complicated. ...
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2answers
126 views

Unsuccessfully trying to iteratively run gdal_polygonize in a batch file [closed]

Thanks in advance for your help with this. I've been reading, experimenting, and banging my head against the wall for a couple days on this, and could really use some assistance. This is my first ...
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1answer
51 views

Associate points with polygon QGIS 2.2

I want to associate a point layer with a polygon layer so that I can do zonal statistics. In the image below, the polygon layer represents roughly the metro area of a certain city. The point ...
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0answers
47 views

How to get the boundaries of a polygon by property

I have the cartography of my city (Santiago) and i need to obtain the nodes that conform the hull (not necessarily convex) of different districts, the boundaries. Each node has the same "DIS"( ...
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1answer
106 views

gdal's polygonize function (via qgis) is not turning monochrome rasters into readable shapefiles regardless of inversion of color scale

I've tried polygonizing this monochrome bitmap as this: and this: and either way it ends up looking like this when (zoomed in) after gdal's polygonize operation: Is there any way I can tell ...
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1answer
149 views

Polygonize(raster to vector) [closed]

I have been install QGIS 2.0.1.when I use Polygonize (Raster to vector)for convert jpg to shp I get error message such as: C:\windows\123.exe is not recognized as an internal or external ...
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2answers
113 views

Low resolution raster conversions to vector yielding millions of single pixel polygons. Trying to merge all directly adjacent polygons

I'm trying to scan plain pdf maps containing color-coded geographic regions and convert them into undifferentiated (I don't actually need them to contain any attribute data) overlays. My workflow is ...
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1answer
60 views

Is there any way to add an area column to new shapefile created from raster with gdal's polygonize in the same step?

I've been going through a fairly lengthy process of polygonizing very intricate raster images, then creating a new layer with the extra area attribute, so that I can then remove the millions of tiny ...
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2answers
221 views

How do I create a polygon layer from multiple touching line segments in QGIS?

I'm trying to create a base map for a Maine Coastal area, and wanted to create a polygon layer of the land cover from the coastline in QGIS. Whether I created the coastline vector layer from the USGS ...
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1answer
459 views

GDAL polygonize lines

I have a raster file containing roads (left image). I polygonize the raster file with GDAL (see the script below). In the end I like to have vector lines. However GDAL only gives me something like ...
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1answer
230 views

GDAL polygonize only certain raster values

I want to polygonize a raster file with GDAL. I only want to rasterize cells with a value of 0. Is it possible to specify that within the polygonize function or do I have to modify my raster before ...
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0answers
123 views

Why is GDALPolygonize so much slower than ArcGIS Raster to Polygon?

I am attempting to polygonize a raster using GDALPolygonize() in a Python script. The script began polygonizing yesterday at 5pm and is still polygonizing now at 9:30 am. I have no clue how far ...
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1answer
326 views

Polygonize.py: AttributeError: 'NoneType' object has no attribute 'CreateDataSource'

Given a topographic raster tif of an european country where elevations are simplyfied to either 0, either 200. How to create a polygon ? Comment: With the following polygonize.py command: ...
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1answer
221 views

Qgis - raster values become integer when Polygonizing

When using the GDAL plugin, "Polygonize (raster to vector)" any values in the resulting vector layer is truncated to integer. I have a raster showing windspeeds in squares of 500*500 meters, in the ...
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140 views

QGIS GDAL polygonize - how to set scale

I've got some old contour plots, paper copy only, that I'd like to be able to put into QGIS. I get as far as a successful polygonize into shp and it looks fine, but the scale is wrong. How might I ...
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4answers
419 views

Generate polygons from a set of intersecting lines

This is a simple and quite common question which has already been asked for different purposes (see this link and this too, for example), here, however, we are looking for not a software package but ...
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0answers
489 views

Line to Polygon via Polygonizer in QGIS

My question is in the same vein as this one. I'm attempting to convert precipitation lines (Precipitación Media Anual) to a polygon for Mexico in QGIS using the Polygonizer plugin. After running the ...
3
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4answers
362 views

How can I create polygons of the area surrounded by roads / lines?

I'm currently trying to create polygons that represent the areas surrounded by roads. The roads are stored in PostGIS as points / lines so I have flexibility over what I can do with them. I'm ...
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219 views

Does Polygonize in QGIS 1.8.0 work correctly?

Does anyone else have issues with the Polygonize function in QGIS 1.8.0. When i use it is to extract details from larger raster images, through raster calculator, then polygonizing the resultant ...
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1answer
296 views

Polygonize function doesn't overlay the shape file over the raster file

To convert the raster into a shapefile I use raster->conversion->polygonize but QGIS doesn't open the new layer overlayed the first (the raster) but reflected above it. I read this question ...
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116 views

Why doesn't Polygonizer copy the line ids to my polygonized shapefile?

I am trying to convert a line shapefile into a polygon shapefile using Polygonizer plugin, and when my new polygons are created all the cells in my id field are "Null", although I have clicked "copy ...
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1answer
113 views

From Raster to Masked and Filtered Polygon Vector

I have a set of rasters (geologic risk) from which I want to extract zones with a specific color, clipping them with a polygon (administrative borders), outputting a shapefile. I'm using QGis (and ...
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0answers
18 views

Raster to Vector seems not to work [duplicate]

Possible Duplicate: Qgis polygonize problem - DLL load fail When I'm trying to invoke the Polygonize Module in the Raster Tab I get the following error message (I did give bothe the source ...
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1answer
710 views

DLL load error with Gdal polygonize in QGIS 1.8 (windows 7) [duplicate]

Possible Duplicate: Qgis polygonize problem - DLL load fail [I had already posted this question, but was closed and redirected to a supposedly duplicate question. I'm re-posting since I ...
4
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1answer
190 views

How can I fix DLL loadfailed with Polygonize in QGIS 1.8? [duplicate]

Possible Duplicate: Qgis polygonize problem - DLL load fail I'm getting the following error message when I try to use the polygonize tool in QGIS 1.8 (windows 7): Traceback (most recent ...
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1answer
417 views

polygonize and raster tools [closed]

ok simplest question i have asked i think. but im a running QGIS 1.7.4 and there are no other tools in the dropdown menu other than raster calculator. I have seen in a lot of online demos tools below ...
2
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0answers
175 views

Polygonize problem [duplicate]

Possible Duplicate: Polygonize function doesn’t overlay the shape file over the raster file When using "Polygonize" in Quantum GIS, I'm getting a polygon shapefile output that is a mirror ...
5
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1answer
721 views

Qgis polygonize problem - DLL load fail

I have a raster file and I want to perform the method "polygonize". Then the problem occurs, that is shown on the screenshot. It doesn t have anything to do with the rasterfile format, I veryfied. ...
2
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1answer
2k views

How to convert lines to polygons using NetTopologySuite?

I am trying to convert lines to polygons using NetTopologySuite(a C# port of Java Topology Suite JTS). I ran the sample console code succesfully and it generated two polylines. I then tried to run ...
5
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3answers
600 views

Convert polyline with Left ID and Right ID to polygons with ID

I have a polyline shape file which contain Left Id and Right ID information and struggling in converting this polyline layer to polygon with ID via arcpy. I am using ArcGIS(editor) license so feature ...