Tagged Questions

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

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1
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0answers
147 views

Personal Geodatabase not recognized as valid datasource in the last QGIS Windows Weekly build (64 bits)

I was using Personal Geodatabases in QGIS without any problem but it's stopped to work since I installed the last 64 bits weekly build for Windows (1.9.0-35-Setup-x86_64). I'm now receiving an ...
4
votes
2answers
570 views

Reduce the resolution of a shapefile in R (or QGIS if necessary)

I'm using shapefiles of history U.S. state boundaries from NHGIS to make maps in R. These shapefiles are much higher resolution than I need when making maps at the scale of the country: over 2 million ...
0
votes
1answer
115 views

Calculate attribute height of point data

I have an x (easting), y (northing) and z (height) values associated with my point shapefile. I would like to calculate the z values from the DTM I have - how do I do this in QGIS? I am fairly new ...
3
votes
1answer
869 views

How to load a NetCDF-file into QGIS using Python?

I have a CF-conform NetCDF-file which can be loaded into Quantum GIS (Version 1.8) by using the "Add Raster Layer"-button and subsequently choosing the file and the raster layers of interest. This ...
2
votes
1answer
89 views

How to drill down through multiple polygons/points in QGIS?

I have a layer that has multiple polygons sitting on top of each other, is there a way to easily scroll through those polygons that overlap each other? Thanks
3
votes
2answers
420 views

Which Windows OS is supported?

Please can you tell me which Windows OS Quantum Desktop supports. i.e. Windows 7, XP, Vista etc.
2
votes
1answer
218 views

QGIS Arch Linux compilation error

Just pulled QGIS from git and am trying to compile it, here's the relevant error: [ 89%] Building CXX object python/CMakeFiles/python_module_qgis_core.dir/core/sipcorepart3.cpp.o In file included ...
2
votes
2answers
136 views

How to extract coordinates from a coastline layer?

I have downloaded QGIS and the Natural Earth base maps. I'd like to somehow get a list of coordinates of a selected coastline. I've got the 10m_coastline layer selected to what I want but can't see a ...
0
votes
1answer
91 views

Add image from my computer for background in Print Composer?

Add image either by dropdown or icon does not produce any kind of dialog box where I could upload an image. Item properties is checked and showing in the right hand panel, but it's blank (no options ...
1
vote
1answer
164 views

opening older 9.x Esri .gdb in QGIS?

I want to open an Esri .gdb with QGIS. I have adjusted GDAL and it works fine with an example .gdb provided on another thread on the topic. I still cannot open the .gdb of interest to me and suspect ...
0
votes
1answer
55 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
votes
2answers
395 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 ...
1
vote
1answer
355 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 ...
1
vote
1answer
707 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?
0
votes
1answer
98 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
votes
2answers
311 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. ...
1
vote
0answers
76 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
votes
2answers
775 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 ...
3
votes
3answers
611 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
votes
1answer
91 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
votes
0answers
92 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
votes
1answer
96 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 ...
-1
votes
2answers
96 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
45 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
vote
1answer
92 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
votes
1answer
422 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 ...
0
votes
1answer
80 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. ...
2
votes
0answers
19 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
votes
2answers
68 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
203 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
544 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?
0
votes
1answer
44 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
232 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
votes
1answer
430 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 ...
1
vote
1answer
823 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. ...
1
vote
0answers
90 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 ...
1
vote
1answer
165 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
votes
1answer
102 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
vote
1answer
206 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
86 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
votes
1answer
315 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 ...
4
votes
1answer
692 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
votes
0answers
69 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
votes
1answer
72 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
votes
1answer
157 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 ...
0
votes
1answer
186 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 ...
4
votes
2answers
241 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 ...
1
vote
1answer
137 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
vote
3answers
522 views

Projection parameters for Gauss Kruger 7 zone Serbia

I can not set parameters for Gauss Kruger 7 zone Serbia
1
vote
1answer
181 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 ...