Questions tagged [qgis]

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

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8
votes
3answers
4k views

QGIS and Raster Mapping in 'Seamless' layer

I would like to use Ordnance Survey base mapping in QGIS. I would like to set up something like a seamless table in MapInfo. I think that the equivalent in QGIS is a Virtual Raster Table. The files ...
2
votes
4answers
5k views

Export to new projection in QGIS 1.7

Suppose I have layers A and B. I don't know their projections but by the looks of the map I know they are not the same. In QGIS 1.6 I would use one of my favorite features: Vector> Data ...
4
votes
2answers
520 views

Total newbie. Creating map from aerial photo of golf course in QGIS

I have a aerial photo in tif with a tfw file of the golf course that I work at. I would like to create vector data of different features on the course such as greens fairways tees, etc. to calculate ...
37
votes
5answers
26k views

Joining attributes from nearest point in QGIS?

I have two layers with points, call them A and B, each with different attributes. For each point in A I want to join all the attributes from the nearest point in B. Ideally this would also include ...
36
votes
5answers
18k views

Identifying clusters in vector point data using QGIS?

I have a vector dataset of rural broadband data-points (how fast, etc.) and I'd like to explore if there are clusters of points with similar characteristics, and to plot polygons encompassing them. ...
1
vote
2answers
3k views

QGis import partial PostGIS layer using query builder

I'm sorry, but I'm terribly new to the GIS scene (and PostGIS & QGis). I have loaded a whole bunch of OpenStreetMap data into a PostGIS database and successfully drawn a map using Mapnik. Now I ...
14
votes
5answers
24k views

How to Zoom in QGIS Print Composer Without a Scroll Wheel

I am attempting to print a simple map from QGIS in portrait orientation. When I use the "Add New Map" tool it brings the map in at an extent which matches my original data frame if I were to use ...
1
vote
1answer
451 views

Python console not loading with QGIS1.7-Ubuntu 10.04.2 LTS lucid,

Any tips on how to get the Python console working on Q-GIS (Quantum GIS)? (Its not working from the software's menu.) System: Python 2.6.5 QGIS1.7 OS Linux: Ubuntu 10.04.2 LTS lucid Error message ...
57
votes
11answers
62k views

Removing small spaces (slivers) between polygons?

I have a set of polygons representing administrative districts. The districts were digitized by hand, and there are small spaces (slivers) between polygons where the polygons should be touching. How ...
3
votes
2answers
983 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. I am struggling to get ...
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 ...
31
votes
6answers
39k 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-file) containing people who work in each building. So I have ...
6
votes
1answer
2k 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
904 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
307 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
486 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
19k 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
3k 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
303 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 ...
3
votes
2answers
1k 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, ...
66
votes
5answers
110k views

Clipping raster with vector boundaries using QGIS

In 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 can I clip this ...
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
7k 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 ...
26
votes
5answers
11k 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 ...
16
votes
5answers
26k 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
465 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
2k 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: ...
53
votes
8answers
17k views

Switching line direction in QGIS

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, however I can't seem to find anything for QGIS. Does anyone know of a tool to do ...
3
votes
1answer
265 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 ...
3
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
783 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 ...
14
votes
4answers
4k views

Removing band from raster in QGIS

When I process a raster in QGIS it creates a second band. It appears that the band has no useful data. I like to use the Raster Colours Tool and it will not accept a raster with anything more than one ...
3
votes
2answers
2k 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 ...
53
votes
7answers
129k 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 ...
8
votes
1answer
653 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
858 views

QGIS, AutoCAD and Google Layers

I have 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
5k 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
13k 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
3k 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?