0
votes
0answers
32 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"( ...
0
votes
1answer
46 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 ...
0
votes
1answer
70 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 ...
1
vote
2answers
99 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 ...
1
vote
1answer
138 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 ...
0
votes
0answers
119 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 ...
1
vote
0answers
431 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 ...
2
votes
4answers
252 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 ...
0
votes
0answers
200 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 ...
1
vote
1answer
245 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 ...
3
votes
0answers
108 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 ...
1
vote
1answer
599 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
votes
1answer
178 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 ...
2
votes
1answer
329 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
votes
0answers
174 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
votes
1answer
618 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. ...