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

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5
votes
2answers
158 views

Using field calculator to delete specific contours

I have 3 contour shapefiles with 25m, 50m and 100m equidistance. Now I want to delete in the 25m-shp-file every **50m and **00m contour and in the 50m-shp-file every **00 contour. How can I show them ...
5
votes
1answer
784 views

Distance Matrix tool in QGIS. How to get result in metric? [closed]

I'm trying to calculate the distance between points in layer with distance matrix tool. And keep getting strange results no matter what. Like this MASTER ------------SLAVE ---------------- DISTANCE ...
5
votes
2answers
3k views

Can I export a polygon shapefile to a Garmin device?

I want to export the boundaries of a parcel to my GarminMap 60CSx. I downloaded a parcel map from the county, and I want to use it to walk the perimeter. Does the .gpx format support polygons? Or is ...
5
votes
2answers
3k views

Calculate area of intersecting polygons in QGIS

I have two collections of shapefiles: 1 - postal codes, administrative and political areas 2 - various land use categories like parks & allotments, and points like trees I want to produce ...
5
votes
1answer
585 views

How to reproject a raster in QGIS?

I am a history teacher and I like to make my own maps (I can never find exactly what I want). I am using QGIS 1.8 and Natural Earth data. I want to reproject their cross-blended hypso rasters into ...
5
votes
2answers
1k views

Where can I get information on QGIS beta versions?

While searching for information on some qgis functionality on the web, i noticed several times, people using version 1.9, however this version is probably some beta (or so i thought) but i cant seem ...
5
votes
2answers
1k views

How to compare two DEMs and show their difference?

I want to compare my DEMs (ASTER GDEM2 and SRTM4.1). I know, that the GDEM has some extreme "holes" with totaly wrong elevations (I found 3 of them in my working area). Now I need to know, if there ...
5
votes
3answers
1k views

How to produce a singlepart featureclass with unique IDs for each spatially non-connected polygon?

What is the best method to convert a singlepart shapefile (i.e. one record that contains several non-connected polygons) into a mutlipart shapefile? --EDIT For clarification the original question ...
5
votes
1answer
921 views

Why do TIF loaded into PostGIS lose their colormap?

I have successfully loaded a TIF image (using raster2pgsql) into my PostGIS 2.0.1 database. I can load the raster image into QGIS and it displays in the correct space. However, it has lost all colour ...
5
votes
1answer
2k views

Is there a way to export QGIS layers to KML?

has had anyone had any luck with the new experimental plugin qgis2kml? I keep getting the error msg layer : format not yet supported I had a look but the author has not provided any documentation, ...
5
votes
1answer
2k views

Features to 3D from 2D in QGIS

Is there a way to convert 2D features to "3D" features in QGIS? I know there is a way to do this in ArcMap by using an attribute value in the attribute table, but I am looking to do this with ...
5
votes
1answer
466 views

How to handle spatial join 10 chars field name limit?

When I try to perform a spatial join between a point and polygon file, I get a notice saying spatial join will not be performed because following field names exceed 10 Characters. Kindly help to ...
5
votes
1answer
2k views

How to do Kernel density analysis in QGIS 1.7?

Do someone have some suggestion? We would like to tray Kernel Density analysis as we did with ArcGis using QGIS?
5
votes
1answer
698 views

Is it possible to setup fiddler to capture requests from QGIS

I want to know if it is possible setup fiddler to capture WMS/WFS requests from QGIS and how to do it. Fiddler is capturing the requests from MapInfo and I don't remember making any setup in fiddler ...
5
votes
4answers
4k views

Workflow for DXF interchange with QGIS

What is the best method of importing/exporting dxf files with QGIS ? I work in an engineering field and we use CAD and specialist design programs, and often go through several iterations during a ...
5
votes
1answer
1k views

How can i delete multiple nodes, for a polygon, with Quantum GIS?

I know how to select a single node and delete it. I can also click-drag to select MULTIPLE nodes. But if i click delete, only one node (from the higlighted list) is removed. Can I delete all the ...
5
votes
1answer
604 views

How to calculate Line Density in QGIS?

I have a map of fracture distributions over an area and I would like to calculate the density distribution of fractures that intersect a moving window with a specified radius. Is there a way to ...
5
votes
3answers
790 views

How to place multiple symbols on one polygon centroid?

I am using QGIS for visualizing the health conditions of elderly living in an old age home, some of the elderly have multiple medical device with them and I want to show them on the map. Suppose I ...
5
votes
6answers
642 views

Southern hemisphere projections for Landsat upsets GRASS

Hi All 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 ...
5
votes
2answers
512 views

Distribute points respect to features using Quantum Gis

I want to know if there is any tool to make points with respect to selected features in a theme? Using: vector, investigating tools, regular points you can do it but not with respect to a selected ...
4
votes
1answer
84 views

In which way is height information stored in a DEM?

I'm struggling with different DEM data, because I don't know how to convert the height information in meters. When I load ASTER and SRTM tifs in QGIS, it shows me the spectrum of the grayband (0 to ...
4
votes
2answers
424 views

QGIS relations widget in custom form

I've just begun exploring QGIS relations option, now in version QGIS 2.2, details here: http://blog.vitu.ch/10112013-1201/qgis-relations This is a great implementation of something I've been ...
4
votes
2answers
224 views

Create A Maximum-Value Composite QGIS

I am looking to create a Maximum-Value Composite raster in QGIS I have three raster images: Oct 2012 Nov 2012 Dec 2012 All are in TIFF Format, Float32, EPSG:4326 - WGS 84 I want to stack these ...
4
votes
2answers
107 views

How to tell QGIS where to start marker line interval?

I want to tell QGIS where to start with a marker, like: use 3 markers, start at positions 0, 2, 4, and apply an interval of 12 to each marker. However, after searching for hours, I haven't found a ...
4
votes
1answer
272 views

Python error with open layers plugin QGIS 2

I've been using QGIS for a while but since using QGIS 2 the OpenLayers plugin doesn't work for me on my home pc. (However, I have installed the same version at my workplace with success.) I have ...
4
votes
1answer
327 views

Historical U.S.G.S. Georeferencing

I have downloaded a historical USGS map that is suppose to be a geoPDF. My understanding is that QGIS cannot directly read geoPDF's. I have not had any luck in converting it to a geoTIF in order to ...
4
votes
0answers
326 views

PyQGIS CRS on the fly reprojetion

As a first step of a pyqgis plugin I'm trying to import several shape files at once. To get them aligned, using the GUI, I'd enable on the fly reprojections and set the project crs to WGS84. I'd then ...
4
votes
1answer
180 views

Can county level info be brought into a map?

I have a csv file of Clovis projectile points that were recorded only with the county in which they were found, no coordinates at all, no shapefiles. Is there a way to bring these into a state map ...
4
votes
2answers
974 views

Total of attribute field of point layer per polygon layer

I have a polygon shapefile of many lakes, I also have a point shapefile of locations on those lakes where fish were caught. The point shapefile contains the attributes: Fisherman_iD, Fish_Caught, ...
4
votes
2answers
414 views

Can't select layer to upload to GPS

I'm trying to upload a vector layer to my Garmin GPS unit. I've saved it as GPX (WGS 84); opened the GPS Tools dialogue in QGIS 1.8; selected the "Upload to GPS" tab; and clicked on the "Data layer" ...
4
votes
3answers
2k views

How to install QGIS 1.8 plugin Georeferencer?

My question is about qgis 1.8 georeferencer plugin. I installed the new version qgis 1.8 but I don't have the georeferencer plugins, how do I install it? I used the georeferencing plugin with QGIS 1.6 ...
4
votes
2answers
444 views

QGIS saving analysis output as Postgis table

i am using QGIS and Postgis together. I can load data in Postgis and than i import it to QGIS. But i am trying to save an analysis output (example: buffer analysis, voronoi polygon or SEXTANTE ...
4
votes
2answers
399 views

Data security for GIS Data (Esri shape files,Auto-cad files)

This is regarding security for GIS Data (in Esri & open source) (Esri shape files,Auto-cad files etc.) Does anyone know how to assign a password to or encrypt shapefiles OR CAD Data? I have ...
4
votes
1answer
653 views

Unit of $length in QGis Field Calculator

I'm calculating field of various features in my shapefile using QGis. I'm getting some sample length as 0.134914579766986. I want to know in what unit (eg: meters, km etc) is the above value ?
4
votes
1answer
920 views

Is there a silent installation command without the desktop shortcuts? [closed]

I installed QGIS with Microsoft SCCM 2012 and I want to make a silent install without desktop shortcuts. I managed to do a silent install with / S but I found no s command to delete desktop ...
4
votes
4answers
739 views

TIN interpolation crash in Qgis

I have problems using the function TIN(linear) interpolation in Qgis. The program crashes when larger areas is interpolated. Map properties: vector map, Geometry typ = Point, features in this ...
4
votes
1answer
1k views

Qgis - How to change GDAL version

im working on Ubuntu 12.04 server; i noticed this when i installed additional support for ECW format into the GDAL 1.9.1 which worked ok. Then i tried to add ECW files to Qgis but it said they still ...
4
votes
1answer
2k views

Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database

This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc. I have tried the ...
4
votes
2answers
517 views

How to represent an imaginary flat world in QGIS without using a round-world CRS

Like one or two other users, I'm interested in using QGIS to map an imaginary flat world. A previous answer suggested simply refraining from defining a CRS for such a world, but I cannot seem to make ...
4
votes
0answers
380 views

Map is missing when I “export as image” via print composer [closed]

I have point data on a vector layer that prints accurately via print composer (when I "export as image"), however my map below either does not show up or shows up at an incorrect scale. I used ...
4
votes
5answers
830 views

Elevation correction ASTER GDEM2 (+10m)

My ASTER GDEM2 has a average elevation error of -10m for my area. (I testet it using 90 defferential GPS reference points and compared it with old Topo25, SRTM, and GoogleMaps). I would like to ...
4
votes
1answer
895 views

In QGIS map composer, how do I get the Item Properties dialog back?

Yes, well if there is button there, one is bound to click it.... I closed both the Item Properties dialogs in Map Composer. And I can't get them to give me any joy no more... QGIS Trunk
4
votes
4answers
3k views

How to import qgis.core to python app?

I'm new to Python. I want to create GIS app with Python using QGIS library on Window 7 64bit. The way I do: install QGIS 1.7.0 I set PYTHONPATH=D:\Program Files (x86)\Quantum GIS ...
4
votes
2answers
465 views

How to fix a raster with wrong Eastings?

I get an error when trying to warp a tif file in QGIS: ERROR 1: Too many points (35721 out of 35721) failed to transform, unable to compute output bounds. I am using QGIS 1.7.0 Wroclaw with gdal ...
4
votes
1answer
817 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 ...
4
votes
2answers
751 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, ...
4
votes
2answers
4k views

How do you Turn on the GRASS plugin in Quantum GIS?

I downloaded and installed Quantum GIS 1.5.0 with GRASS using the OSGeo4W installer on my Windows XP machine. Unfortunately, when I go to Plugins>Manage Plugins I cannot find the GRASS plugin. When ...
3
votes
2answers
61 views

Correlation between a raster and a point dataset

I have an interpolated surface (in raster form) with temperature values and I also have the measurements of temperature in certain locations that belong to the same region (with the raster). I want to ...
3
votes
2answers
196 views

How to set NULL as default value for a date field in QGIS 2.4?

In QGIS 2.4, i am unable to set the default value as NULL if i have not updated any value on date fields. Its automatically taking the current system date. I am expecting to set the default ...
3
votes
1answer
82 views

Is it possible to rotate the *canvas* in QGIS

Can the canvas be rotated so north is pointing in some other direction than defined by the projection? This question answers with respect to the composer, but not the canvas. There is a related 5 year ...