QGIS is a user-friendly, cross-platform GIS application licensed under the GNU General Public License.

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58 views

How to generate raster from vector in QGIS with resolution matching existing raster?

Is there any way to use open source tools (preferably QGIS) to rasterize a vector to create a raster with the same coordinates and resolution as an existing raster? I know that the map size can be ...
2
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2answers
594 views

How can I create a vector layer in PyQGIS from a table without geom column?

In QGIS I've got a Spatialite database containing tables without a geometry column. With the QGIS GUI it is perfectly possible to add such a table as a 'Spatialite vector layer'. But how to do this in ...
3
votes
1answer
540 views

QGIS Shapefiles have the same CRS but dont line up. (Census Tiger Data & State Data)

I have the Census Tiger data for Oregon from http://www.census.gov/geo/maps-data/data/tiger-data.html Then the bottom one of 2010 Census Population & Housing Unit Counts — Blocks. The shp ...
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1answer
1k views

Export all visible layers in map view window to DXF (as one)

I'm looking to find a way of exporting all that is visible in the map view window to a dxf file. That is to say, multiple features from multiple layers, all at once. Can this be done?
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1answer
175 views

Extracting “derived” data [duplicate]

Rookie Question! I have a shapefile in QGIS 1.8.0 of a country with 20000 divisions. I need the area of each division, but this is not a given attribute. When i click on a district, the "Identify ...
4
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2answers
402 views

How do I snip/split polylines at chainages?

What is the best way to snip/split lines at chainages? E.g I have a csv with the uniq ID of the polyline item and a start and end chainage. I want to extract the lines between the chainages stated. ...
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0answers
92 views

level of spatial aggregation of polygons

I am looking for a method that allows me to obtain the spatial aggregation of polygons for each cell of a grid with 10kmx10km resolution. In each cell (10kmx10km), I want to be able to consider that ...
2
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2answers
1k views

QGIS: when using composer to save as image the image has a shift of about 50m [duplicate]

im using qgis 1.8.0; i have two layers turned on, 1 the google earth hybrid layer from the open layers plugin and a shapefile of my own making. i set on the fly projection and everything looks spot ...
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3answers
2k views

How to group and count attribute data?

I have a problem with group same data to count it. for example, i want to group same code to one and count them. i can do it when i use MapInfo (Pic 1) but i can't in QGIS. (Pic 2: i can classify ...
0
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1answer
116 views

Why does my buffer take up the entire screen?

I am using QGIS. I am aware there is a similar question here but the solution (changing the layer CRS) is not working for me. I cannot change my CRS as I am using information for the entire ...
2
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0answers
115 views

Displaying DEM raster in QGIS

Using Raster>Analysis>DEM to display hillshade produces the message "gdaldem.exe had stopped working" so I asked the community. I'm new to QGIS, and I now realise after a little experimentation that I ...
2
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1answer
112 views

Is it possible to destroy a spatial index?

QGIS 1.9 Is it possible to destroy a spatial index? I am noticing that if I generate a spatial index on a set of polylines (within a plugin), split one of the lines, and then recreate the spatial ...
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2answers
121 views

Counting raster points within boundaries in another layer?

I know this question is similar to some out there, but I have tried all the 'solutions' and none of them are working for me. I am using the latest version of Qgis. I have a raster layer with ...
2
votes
1answer
48 views

Placing TIF image on the top of WMS layer

How to place TIF file on the top of WMS layer in QGIS? When I import TIF file, it has different coordinate system, and it is placed far from WMS layer, but I want to put this TIF layer on the top of ...
1
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1answer
117 views

How do I include libfcgi files when installing QGIS on SUSE Linux?

I'm using SUSE Linux Enterprise Desktop 11 SP2. When I try to install QGIS from YAST, it seems that the package "libfcgi.so.0" and "libfcgi.so.1" are missing. Is there anyone else that has experienced ...
2
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1answer
576 views

How to save data from QGIS 1.8 to PostGIS without shapefile intermediate?

Is it possible to save data directly into an existing PostGIS database from QGIS without having to first save it as a shapefile? I know about the SPIT plugin but that requires a shapefile. I want to ...
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1answer
88 views

How to convert polygons to centriods without losing attribute names?

I have a GeoJSON file of polygons and I need to convert it to centroids. Finding the centroid is very easy in QGIS. Problem My attribute names are very long and have a colon between them, e.g. ...
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0answers
20 views

Problem with postgres/quantum converting long/lat to suitable projection/SRID [duplicate]

I'm sure it's a simple question but this is all very new to me and after a lot of internet searching my points are still in the sea! I have a set of UK postcode data that I have converted into ...
2
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2answers
100 views

How to move line segment?

I use Quantum GIS 1.8. I have a polyline layer. I can drag&drop polyline nodes by using "Node Tool". Is it possible to drag&drop line segments of a polyline in order to preserve line ...
2
votes
1answer
267 views

Stratified Random Sampling by ID in QGIS?

I've been playing around with the Random Points tool in QGIS to realize stratified random sampling, but I'm running into a problem where I want my strata to be based on a polygon ID, not each ...
3
votes
1answer
1k views

How to explode multipart polygons within shapefile in QGIS 1.8

I've got a shapefile with polygons, some of which are multipart polygons. I need to create individual polygons out of the multipart polygons. Is there a tool or plugin that can do this in QGIS 1.8?
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1answer
56 views

Select Features by Polygon - Not Displaying the Shape Drawn

I am a relative newbie to QGIS 1.8, have looked through the previous answers, but have found nothing that resolves my issue. I have a number of datazones as polygons on a layer. One of the datazones ...
2
votes
1answer
329 views

KML to shape QGIS conversion [duplicate]

I am trying to import a KML file to QGIS. The KML source file is about 15mb is comprised of polygons with attribute data. The KML imports fine and polygons display but the attribute data is unreadable ...
2
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1answer
561 views

Using Custom Source for QGIS OpenLayers Plugin

I'm using a Custom Map Source for MOBAC that is based on a beanshell script (see below) which renders perfectly in MOBAC. Now, I'd be keen to do the same in QGIS and wonder if it is possible to ...
2
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1answer
864 views

How to import sextante(processing) for QGIS 1.9 (2.0)

In the current QGIS development snapshot the SEXTANTE toolbox has been merged into QGIS and is now known as "processing". This is a good step, but the previous import command doesn't work anymore. ...
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0answers
104 views

SVG trouble in QGIS

I am having some issues using some SVGs that I have created in Inkscape. I am trying to use them in QGIS but they're not displayed properly. This: is how the SVG looks like in Inkscape and how it ...
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1answer
260 views

Can't add qgis repository for openSUSE

Linux noob here. I keep getting "Unable to create repository" when trying to add the repo url on the qgis download page to YaST: ...
0
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1answer
117 views

QGIS for Mac: How to restore menu bar and tool bar in print composer

I managed to hide both the tool bar and the menu bar in my print composer (Mac version 1.8.0). To get the tool bar back I saw you need to click on the menu bar. What then when you also miss the menu ...
1
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1answer
273 views

Mosaic Imagery to Tile Grid

I am hoping to come up with a script that would allow me to mosaic imagery into a polygon tile grid. My hopes is to do this with gdal or QGIS. I am wondering if anyone knows of an existing script, ...
2
votes
1answer
102 views

How do you get a schema report from SHP, PostGIS, or other file type?

All, We're loading City and County data into our database, but looking to remove several fields we don't use. Those fields we do use I'd like our users to simply highlight on a printout I give them ...
2
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1answer
365 views

Sextante in Qgis 1.9 alpha on Ubuntu can't find saga gis 2.1

I am using Qgis 1.9 on Ubuntu 13.04, Sextante is a core part of qgis now. I am trying to access the SAGA 2.1 libraries through qgis and I keep getting a popup window that says SAGA is not installed. I ...
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1answer
266 views

Geocoding using Excel spreadsheet

Can I add a spreadsheet with addresses to QGIS and then geocode it?
5
votes
1answer
1k views

Obtain voronoi polygons which extend till the boundary of another polygon

I have certain hubs (coloured yellow) in a district (coloured light blue). I need to find polygons indicating the closest hub to every point in the district. The voronoi polygons that I obtained ...
0
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0answers
98 views

How to perform a clean re-installation due to dll errors

Following a virus, Qgis won't run and errors saying missing dll. I manually replaced the first missing dll but it now complains about a second one. I suspect that if I simply replace this one it ...
0
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1answer
78 views

How to create more than one mean coordinate in QGIS?

I have a point shapefile with several thousands of points in it. I've split the points up into spatial groups using a vectorgrid and pointcount. I wish to create a mean coordinate for each group of ...
0
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1answer
239 views

Select features from attribute table and then create a new field with the selected attribute data

I have a shape file which contains land use typology for my administrative area. I’m investigating deficiency in certain land uses and there are 2 ‘standards’ that we have to use. These standards use ...
1
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1answer
259 views

Error 'Invalid geography. Antipodal edge…' with Postgis

I have a table in postgis like this CREATE TABLE locations (id int, name VARCHAR(255), pos geography(POINT, 4326)); with a couple of points. E.G. INSERT INTO locations (name, pos) VALUES ...
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2answers
344 views

Wetlands Symbol for QGIS point pattern fill

Is there a marker available anywhere for point pattern fill that resembles the standard wetlands symbol used in USGS topographic and other maps? Any good standard symbol that will be intuitively ...
2
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1answer
181 views

Split polygon into lines

I have a polygon layer which looks like this . I used the QGIS multiparts to singleparts tool and also polygon to lines. In both cases i got this type of result . I want to extract polygon into ...
1
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3answers
842 views

Projection parameters for Gauss Kruger 7 zone Serbia

I can not set parameters for Gauss Kruger 7 zone Serbia
1
vote
1answer
270 views

How do I get an accurate time attribute when importing a GPX layer as a vector

When I import a GPX file in QGIS (as a vector as track points) and I check the time attribute it appears to be 4 hours later than it should be. Interestingly when I take this same GPX file and use ...
2
votes
1answer
457 views

Tracing Boundary Around a Polygon Shapefile in QGIS

I'm looking to create a boundary around this shapefile of street blocks to have show the city limits in QGIS. I tried this solution, (Settings > Snapping Options and enabling the "Avoid Int." ...
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0answers
161 views

Why does the buffer tool keep producing ellipsoid when I want a circle?

I want to create a 50 mile radius around a point. I've got the point as a layer. I've run the buffer tool found in Vector -> Geoprocessing Tools and set the distance to 0.5. Every time I run the ...
2
votes
1answer
92 views

How to get access to layers without geometry?

I have a QGIS project with some layers without geometry. I develop a QGIS plugin. I want to get all my layers by: iface.mapCanvas().layers() but I get only layers with geometry. How I can get ...
3
votes
1answer
249 views

Flatten GIS data to a schematic

I want to take a network of roads and lanes and reduce them to a schematic that shows their relationships but not their geographic shape. A similar concept has been used for the London Underground ...
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0answers
141 views

I have a problem to display the legend in QGIS Web Client

I have installed QGis Map Server and QGis Web Client on Centos 6.4 64-bit operating system, everything works fine except the legend box which is filled with garbage data instead of text (it seems that ...
3
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2answers
673 views

Map walking distance/time from transit stops

I'm working in QGIS and would like to show how far from a bus stop a pedestrian could walk along the street network in any direction for a specified set of walking times (5,10,20 mins etc). I have my ...
7
votes
2answers
2k views

QGIS display world country shape files centered on pacific ocean using Robinson, Miller Cylindrical or other projection

I wish to display a map in QGIS (world country shapefiles) showing all countries but centered on the Pacific area. I am not familiar with Proj4, so is there any way this can be done in QGIS please?
2
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1answer
260 views

Map formats supported by QGIS

May i know whether QGIS supports the following map formats? (1) S-57 Electronic Navigation Charts (Naval Maps) (2) Army/IAF Maps in DGN (3) DTEDO0, DTEDO1 and DTEDO2 (4) GeoTIFF (5) DTED
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1answer
98 views

Census Shapefiles Fit to Land

I'm looking for an oceans or coastlines shapefile that's a more detailed than what Natural Earth has to offer (1:10m). I'm working with 2000 Census county shapefiles, but it doesn't cut out lakes or ...