Questions tagged [qgis]

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

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3
votes
2answers
879 views

Overlaying GPX data on rasters in QGIS

I have a series of raster map images that I would like to use in QGIS and overlay some simple GPX routes over the top to produce a custom map image. This is all quite new to me so please bare with me....
2
votes
2answers
2k views

Problem reprojecting data from personal geodatabase using QGIS

I have a dataset in the form of a personal geodatabase (mdb) and am interested in using certain feature classes for further processing. My problem is - I am using USGS data orthoimagery which comes ...
25
votes
6answers
31k views

Joining multiple records to single feature using QGIS?

I'm trying to create a join/relate in QGIS where I have a shapefile of buildings and to that I would like to join a non-spatial table (.csv) containing people who work in each building. So I have ...
6
votes
1answer
1k views

How to force QGIS Centroid Fill inside the Polygon?

I would like to use a centroid fill to enable me to place a letter inside a polygon. The advantage of using a centroid fill is that it also shows up in a legend, whereas labelling the layer would mean ...
6
votes
1answer
896 views

Vector Legend item names in QGIS Map Composer

Is it possible to get the text for a legend item to go over multiple lines? I have some long item names and I have a set legend width that I have to use. Without being able to make the text go over ...
5
votes
2answers
298 views

How to deal with multitype data sources in QGIS?

Today I was trying to import a DXF to Qgis, the result is that qgis displays everything LINES and POINTS but it only displays options for the POINT objects. When I try to export to a shapefile, it ...
2
votes
3answers
482 views

Has QGIS 1.7 been released as a stable version yet? [closed]

Has QGIS 1.7 been released as a stable version yet? I see on the QGIS site the windows download on the is still referring to 1.6 and the OSGEO4W install has 1.6.0-7 as the stable release. I had seen ...
34
votes
2answers
16k views

Styling road maps with QGIS?

I am trying to design a beautiful map using QGIS. There is a similar question here Seeking QGIS tutorials and web resources? but I would like to focus on "designing a map using QGIS". I was looking ...
6
votes
1answer
2k views

Calculating Standard Deviation in QGIS?

Does anyone know of a way to find the standard deviation of an attribute lying within any given polygon? The plugin dialog "Join Attributes by Location" gives only the options Mean, Min, Max, and ...
4
votes
2answers
301 views

How can I make my data efficient and “light” to do 3D Visualizations in Google Earth?

As a test run, I'd like to visualize population on census blocks for a few states (New England for example). I assume that the kml to do this will be huge, when you factor in the census boundaries and ...
2
votes
2answers
928 views

How to get a composition name in Qgis python console?

In Qgis python console: I want to populate a list with compositions names, like in Composer Manager, but I can't figure out how to get the names (titles). So far: composerlist = self.iface....
4
votes
1answer
3k views

How to import qgis.core in a Osgeo4W installation?

when I try to import qgis core module from python: from qgis.core import * I get this error: ImportError: DLL load failed: The operating system cannot run %1. Searching the web I found that I need ...
5
votes
1answer
1k views

How to insert 3d line into postgis database?

I have 3D line which I exported from GRASS in .shp format. When I try to insert this line to Postgis database with QuantumGIS, it gives an error: ERROR: Invalid type name - valid ones are: ...
6
votes
1answer
1k views

Can I specify a point and get all features within a certain radius of this point?

I have recently shifted to QGIS from ArcGIS and am looking for some help/pointers with the following: Does QGIS have a method by which I can specify a lat-lon coordinate (or a utm x,y coordinates, ...
57
votes
4answers
74k views

Clipping raster with vector boundaries using QGIS?

I am using QGIS. I would like to clip a raster precipitation layer using an admin boundary layer that is vector data. However the geoprocessing tools seem to be usable only for vector data. How ...
13
votes
2answers
23k views

How to enable projection transformation in QGIS

My QGIS project has two layers, one layer is retrieved by Google layer plugin which fetches the static Google map image whose CRS is +proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +...
16
votes
2answers
2k views

How to overcome field truncation when converting OSM to shapefile with QGIS?

I am trying to convert an OpenStreetMap file into a shapefile, but I am having problems with the "tags" field being cut-off after 80 characters. With QGIS 1.4, I use the OpenStreetMap plugin to 'Load ...
26
votes
6answers
6k views

Creating a small web-mapping/map-tiling service

I am looking for a small-scale and easy way to present one or more polygon shapefiles online (on a municipal website without any existing map-server infrastructure, to be precise). Right now, I'm ...
7
votes
6answers
2k views

Southern hemisphere projections for Landsat upsets GRASS

Does anyone have the last word on why Landsat scenes don't project in the southern hemisphere. This causes no end of trouble in GRASS, less so in QGIS. What I mean is, take an original scene from ...
8
votes
1answer
2k views

How to create point labels from midpoints of road polylines in QGIS?

I have a road polyline layer (singlepart ie has several features per road, grouped by an id field), and i want to (after merging the parts) find the mid point of the resulting lines. This is for roads ...
25
votes
5answers
10k views

Obtaining print quality PDF or PNG output from QGIS?

I work with people who use ArcGIS Desktop and they have found the best resolution output images are made by creating PDFs. They tell me that *.png and the rest out of ArcGIS Desktop are not ...
14
votes
5answers
23k views

Reading ODBC connection using QGIS? [closed]

I have a co-worker who manages a large MS Access database that contains X & Y fields for various locations he tracks. We have previously exported the data to CSV and used the QGIS Delimited Text ...
1
vote
2answers
400 views

Is it possible to save PostGIS connection string in OGR add-in to QGIS?

In QGIS I've saved a couple of PostGIS connections for adding data. This works fine. I've been unable to save the connections in the OGR layer converter add-in though. Has anyone found a way to do ...
6
votes
3answers
1k views

Qgis is slow with complex 'postgis query' layer. How to speed up?

I have a postgis layer in Qgis that is a result of a complex query. Every screen update, Qgis runs the Query again and that's slow. Any suggestion on how to speed up? EDIT - Here is the query: ...
49
votes
6answers
14k views

How can I switch line direction in QGIS?

Something that is hopefully pretty easy. I would like to be able to swap the direction of a polyline/line in QGIS. I made a custom tool to do this in MapInfo a couple of years ago, however I can't ...
3
votes
1answer
254 views

SVN Version of GRASS and QGIS

I have GRASS6.5 SVN installed and wanted to go for SVN installation of Quantum GIS in Ubuntu 11.04. So as instructed in QGIS Wiki, I added the qgis repository to my sources.list file. Now I am able to ...
2
votes
2answers
7k views

Hyperlink relative paths to files in points layer in QGIS?

I would like to add hyperlinks to each point in a points layer in QGIS 1.7.0 running on Mac OS X 10.6.7, but I have several requirements: (1) Each hyperlink has to be a relative path to the linked ...
7
votes
3answers
670 views

Grass v.rast.stats returning null values

I have a vector layer (polygon) and a raster layer. The raster layer holds values for height above bald earth in a field called "value". I'd like the vector layer to inherit either the mean or the ...
5
votes
1answer
1k views

Can QGIS resample Rasters during display?

When I was using ArcGIS a user could resample a raster during the display (I think via layer properties under the display tab). This would smooth the appearance of the raster so it wouldn't appear ...
12
votes
4answers
2k views

In QGIS, how do I remove a band from a raster?

When I process a raster in QGIS it creates a second band. It appears that band has no useful data. I like to use the Raster Colours Tool and it will not accept a raster with anything more than on band....
3
votes
2answers
1k views

Change output file type in QGIS georeferencer?

I have successfully georeferenced a raster file via the Georeferencer plugin (Georeferencer GDAL Version 3.1.9) in QGIS 1.7.0. However, I noticed that the output georeferenced raster file is in TIFF ...
47
votes
7answers
92k views

Getting list of coordinates for points in layer using QGIS?

I've got a layer in QGIS that is comprised of points. Its attribute table doesn't have (show) the corresponding x and y coordinates for each point. Is there a way for me to extract a list of ...
4
votes
1answer
1k views

Matching ArcGIS and QGIS coordinate systems

I have the following info for a feature class in ArcGIS that is supposed to be in WGS 1984/UTM 16N projected coordinate system: Projection: Transverse_Mercator False_Easting: 500000.000000 ...
6
votes
2answers
2k views

Creating polygons from one to many relationship of points using QGIS or PostGIS?

I have a set of polygons that are in a one to many relationship with points. The polygons are administrative boundaries and the points have information on companies and percentage of ownership . I ...
7
votes
1answer
534 views

QGIS composer - How can I eliminate striping across transparent raster layers?

I have downloaded QGIS dev version 1.7.0-114 and I have come across some weird behaviour in the composer. I create a map with a hillshade and a transparent DEM ontop of it, pretty standard stuff. ...
2
votes
1answer
824 views

qgis, autocad and google layers

Ive downloaded qgis and loaded the google layers plugin. I have imported a dxf cad drawing. Question is how do i place the shapefile in the correct place on the map? Also how do i tell google ...
4
votes
3answers
4k views

JPG file all black when added as raster in QGIS

I add a new raster layer in the latest QGIS and select a JPG file, but it is all black. I tried adding the TIF version of the same image and that worked. What is it with the JPG, and how should I ...
3
votes
1answer
2k views

How to add images containing attributes in QGIS?

I am new to QGIS. I know how to add vector and raster files into QGIS. I have some satellite images taken at different times of the same location. In addition, there are some annotation data ...
39
votes
4answers
12k views

How to migrate from ArcGIS for Desktop to QGIS? [closed]

Our lab has about 10 projects in ArcGIS 9 (a couple are made in ArcGIS 10) that includes the following in each: A georeferenced (WGS1984 geographical projection) raster seafloor image, representing ...
5
votes
2answers
1k views

Plugin for average distance from node to polyline in QGIS?

Is there a plugin available that will calculate this? EDIT 1: The red polyline is the average distance of the point to the black polyline. The red polyline is what I want to display. Alternatively, ...
2
votes
3answers
2k views

Extracting data from GeoMedia *.mdf database without using GeoMedia?

Is it possible to extract data from Geomedia .mdf without Geomedia? Preferably with use of QGIS or ArcGIS for Desktop?
12
votes
2answers
5k views

What is the standard Mercator projection?

I'm using QGIS in order to re-project a shapefile I have into "Mercator" so that something like protoviz understands my co-ordinates. Protoviz tells me "Mercator" (http://vis.stanford.edu/protovis/ex/...
6
votes
1answer
1k views

QGIS WKT Raster Plugin error, what does this mean?

I have been playing with the WKT Raster plugin. I have installed the WKT Raster experimental binaries in PostGIS successfully and followed the instructions in the read me to the letter. When i am in ...
5
votes
2answers
2k views

How to return raster values based on polygon (shapefile) boundaries in QGIS?

How to return raster values based on polygon (shapefile) boundaries in QGIS? Is this an elementary question, because I am finding it hard....... Ideally I would like a neat workflow as I am likely to ...
5
votes
1answer
2k views

Transform polygon to equivalent circle, QGis

I have a polygon and I'd like to find the radius of an equivalent circle from a particular point within the polygon. The polygon would have a large (infinite) number of points evenly distributed ...
4
votes
1answer
5k views

Saving Google Earth Location: OpenLayers Plugin in Quantum GIS

I use the OpenLayers plugin to load Google Earth Layers in Quantum GIS to digitize/identify certain features. As my work is large occassionally I have to quit Quantum GIS to resume later. The problem ...
22
votes
5answers
12k views

A SQL console in QGIS

I know QGIS comes with its field calculator, which is not bad. It also comes with ftools which permits several operations on geometry and attributes. But we often need more control and I haven't seen ...
19
votes
7answers
33k views

How do I calculate the latitude and longitude of points using QGIS?

I'm trying to figure out how to calculate the lat/long of points using the QGIS field calculator. Is there an easy way to do this? I saw a previous related question, but it deals with a more advanced ...
33
votes
2answers
6k views

Can QGIS preserve layers when exporting to PDF?

In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself). When I export from QGIS to PDF, I don't ...
12
votes
3answers
16k views

How to create an “area of interest” polygon mask?

I've created a GP tool using ArcGIS that creates an "area of interest" mask from selected features. Effectively it creates a new donut polygon layer where the hole was the previously selected ...