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

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14
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5answers
2k views

Find pseudo nodes in free GIS software

Software gvSIG OA Digital Edition 2010 have tools topology for finding pseudo nodes in linear geometry. I set cluster tolerance 0.00002 and maximum number of errors -10000 for 20000 link count linear ...
23
votes
5answers
6k views

How to identify clusters in vector point data?

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. ...
10
votes
2answers
2k views

How do you display related records in QGIS?

Coming from an esri background I have always used relationship classes in a gdb to display records related to a feature. Eg. Relate 1 survey point to many documents, photos etc. Does any one know how ...
6
votes
2answers
7k views

How to connect to Postgres with QGIS?

Oddly, it should be simple, but I can't connect to a local PostGIS database. My installation is with Mac OS X (10.8), Postgres.app (in doc it's said to have PostGIS included) and Quantum GIS 1.8. ...
18
votes
5answers
5k 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 ...
12
votes
4answers
14k views

Feature comparison between QGIS and ArcGIS for Desktop [closed]

I am learning to use QGIS and ArcGIS for Desktop but I cannot find the differences between them. What are the differences between the capabilities of QGIS and ArcGIS for Desktop?
8
votes
1answer
7k views

Create a csv with geometry as WKT in QGIS (and choosing the field delimiter)

Is there a way to choose the field delimiter when exporting to CSV with geometry as wkt in QGIS? I have a shapefile with donut holes and I'd like to export it as a CSV. It's for a partner whose DB ...
8
votes
3answers
15k views

How to export Polygons to CSV with coordinates?

I am very new to QGIS, so please bear with me. I have a ".shp" file, which is contains a set of boundaries for suburbs of Australia. I opened it to QGIS and I would like to export it into a CSV file ...
5
votes
3answers
4k views

3D visualisation with open source GIS software [closed]

I'm searching for QGIS (or other open source GIS software) tools that can analyse XYZ data. Also I'm interested to hear about if anyone have migrated to non commercial software regarding geological ...
4
votes
1answer
2k views

QGIS on Mavericks

I have been trying to install QGIS on Mavericks and I have failed. Prior to installing QGIS, I installed GDAL using homebrew. I also installed Numpy, SciPy and pyqt using the detailed instructions ...
11
votes
2answers
3k views

Is there a good qml or sld file available for QGIS + Openstreetmap data?

I'm looking for a qml file (or equivalent e.g. sld) to allow me to use QGIS to take Openstreetmap data and produce paper maps. I'm re-asking this question (it was asked once or twice over a couple of ...
11
votes
1answer
3k views

How do I build a custom form for entering attributes in QGIS

I've done this many times in ArcGIS and ArcPad but I don't even know where to start building a custom form for data entry in QGIS. I would like to do this for field operations--QGIS would make a good ...
16
votes
6answers
6k views

Generate points that lie inside polygon

I have polygon feature and want to be able to generate points inside it. I need this for one classification task. Generating random points until one is inside the polygon wouldn't work because it's ...
10
votes
7answers
11k views

How to merge lines with slightly different endpoints in QGIS?

In QGIS, I have two lines. The endpoints are near each other, but not quite aligned. I'd like to turn the two lines into one, with the two endpoints merged into midpoints. The closest I've been able ...
6
votes
4answers
2k views

Is it possible to create 3D dxf with OGR?

Does anyone know if it's possible to create a 3D dxf with OGR. I would like to assign our contour lines a z value and export them to dxf for some cad work. PS I know FME can do this, however I would ...
5
votes
4answers
6k views

How to quickly calculate bounding box coordinates of a selected polygon with qgis

I just manually (and somewhat inaccurately I'm sure) retrieved the bounding box coordinates for a county polygon, which is a selection from a larger layer of county shapes. I'd like to be able to use ...
5
votes
4answers
5k views

What is the projection of WGS84 in GIS software?

WGS84 is a reference ellipsoid that determines coordinates of every point on Earth using latitude, longitude and height about the its surface. This ellipsoid is often used as a base to make maps. ...
4
votes
2answers
531 views

Scale and Z factor have no effect on hillshade analysis in QGIS

I used an SRTM DEM to create a hillshade in QGIS 2.2.0. However, the resultant hillshade seems to be vertically exaggerated. Also, changing the settings for scale and z-factor does not have any effect ...
3
votes
5answers
2k views

Creating multiple buffers using QGIS?

I'm new to QGIS and have no programming skills. Is there an easy/uncomplicated way to create multiple buffers around a line feature?
13
votes
1answer
810 views

How to setup QGIS Master and Stable in parallel on one Linux system?

I mainly use the QGis Master (nightly build) for my Debian Linux and I'm quite happy with it. But for educational and demonstration purposes, I now have to work with the Stable(1.8) version. How can ...
10
votes
1answer
541 views

Can PostGIS and QGIS provide dependable multi-user editing?

After considering a few options, I'm trying to give my 15-20 QGIS 2.2 users the ability to concurrently view/edit one or two basic point PostGIS layers, largest one has just 16,000 records. I've ...
10
votes
1answer
688 views

How to render a table with mixed geometry types in QGIS?

I created a table with geometry type "GEOMETRY" AND inserted data of point, line and polygon type. My question is how to show this spatial data Qgis not supporting for geometry type "GEOMETRY".
10
votes
1answer
4k views

How to display geoJSON from an URL in a layer?

I am looking for some type of plugin or code which would allow me to add a geojson URL, define the areas to input the lat/long variables from the visible Qgis canvas map and call/render the results ...
9
votes
2answers
14k 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 ...
7
votes
2answers
1k views

Is it possible to conduct a flood model analysis with QGIS using a DEM?

Is it possible to conduct a flood model analysis with QGIS using a DEM? Need to simulate rising water levels on a 250k map.
7
votes
4answers
5k views

How to change field length in QGIS

I have a shapefile I made in QGIS 1.7.4. One of the fields is a String of length 80. I'd like to make the field accept longer stings, but I can't figure out how to change its length. How do I do this? ...
5
votes
1answer
754 views

Is there a purge function to remove layers from a qgs file which are not present in the Layers pane?

I have some QGIS projects that I've been using for long time, adding and removing layers, updating reference to deleted or moved files etc. Opening with a text editor the qgs file I see that it ...
4
votes
4answers
5k views

Measuring the distance between lines and points in QGIS

Using QGIS - I have a vector of fault lines. I have point data in the form of a csv which I have also loaded into QGIS. I need to know how far each point is from the nearest fault line then enter ...
2
votes
3answers
2k views

How to get shapefile of river from OpenStreetMap?

I dont want to download whole map of an area. I just want rivers and other waterbodies present in an area in shapefiles so that I can use them in Qgis. I tried geofabrik but it is giving whole map and ...
2
votes
5answers
4k views

Is there any way to extract coordinates of a road segment using QGIS?

I add my own road vector data on top of Google map using open layers plugin with QGIS. The vector layer is generated using PostgreSQL DB. Is there any way to extract coordinates of a road segment ?
2
votes
2answers
2k views

QGIS Server Capabilities Response doesn't contain any Layers

This question is similar as this one QGIS Server not working (problem with fast CGI), but with more details: I installed the latest QGIS from trunk on Linux (Ubuntu 11.04) in the non-default location ...
9
votes
2answers
9k views

Is there a way to manually place labels in QGIS?

Is there a way to manually place labels in QGIS? I have a map which has almost-duplicate labels in some places (e.g. E 1st St and 1st St) and I'd like to remove some of them. Also, I'd like to move ...
8
votes
1answer
680 views

How to address the new “Task-Completed” QgsMessageBar in Python?

I am really amazed what huge steps the QGIS development has taken in the last months. The new iconset, the improved Print composer and many more changes to be seen in QGIS 2.0 are really awesome! ...
7
votes
2answers
995 views

Easiest way to create historical street maps using QGIS

I want to make some historical street maps using QGIS. I understand how to upload a historical OS map from DigiMaps to QGIS, but I want to actually 'draw' the streets myself in order to have some ...
7
votes
4answers
2k views

How to close watermarks window in QGIS Openlayers plugin?

I'm using Quantum GIS Ver. 1.7.4. I have upgraded openlayers plugin 0.7 to 0.9. However when I open google satellite, a watermarks/copyright dialog box "Data Peta@2012 ..." appear in the middle of the ...
7
votes
2answers
2k views

Join attributes of point and line layer by location (closest distance) in QGIS

My problem is the following: i have a line shp (target layer) and a point shp (join layer). the second one (point layer) holds an attribute which i want to join with a line layer based on closest ...
7
votes
3answers
6k views

QGIS- 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 ...
6
votes
3answers
2k views

How to set up a Coverage Layer for Atlas Plugin?

Has anybody utilized the Atlas plugin? I am starting to take a look and setting it up on a project. My question is how do you set up the layer that is utilized for the coverage layer. Is there a way ...
6
votes
4answers
11k views

How do I load a .dbf file into QGIS?

I want to use QGIS to extract lat/lng data from the vertices of polygons. There are about 400 polygons, each with maybe 200 vertices. I am having trouble with step one, getting the data into QGIS. ...
4
votes
2answers
2k views

Misplaced Google Maps with OpenLayers plugin in QGIS?

I was using Google Maps with OpenLayers plugin in QGIS with my vector layer with projection EPSG:4326 with google map projection EPSG:3857 and "on the fly" transformation enabled. It was matching ...
4
votes
2answers
592 views

Georeference vector linework

I'm new to GIS and a lot of searching didn't answer my specific question so far, so I hope someone can help me here. What I want to do is creating a small web application to visualize election ...
4
votes
2answers
209 views

Is it possible to edit a layer in QGIS while there is an active query?

I am new to Quantum and I am digitizing polygon layers using the editing features. I would like to apply simple queries ('date > 2012/08/01'), however while the query is active I cannot edit the ...
4
votes
2answers
3k views

How to create heatmap (concentration of points) in QGIS?

There was already a question about it in 2010, where the answer was basically "use QGIS Heatmap plugin". I've also read on QGIS webpage that it is now "implemented as a native C++ plugin" My ...
3
votes
2answers
316 views

how to load the QGIS openlayers_plugin in standalone python script (not the QGIS embedded python console)

if I try to load the openlayers plugin in a standalone application it always fails with False, although paths are set, and plugin shows available. (tested on Ubuntu 14.04, QGIS 2.4, python-2.7) ...
3
votes
1answer
732 views

Hyperlinking in QGIS - Add Data to current window

I am looking to add to my current action in QGIS so that a hyperlinked file will open in the current QGIS window, rather than in a new window. Here is what my action looks like: "C:/Program Files ...
2
votes
2answers
615 views

How to import a 3D DXF file into QGIS with z information as attribute value?

I have a dxf file of 3d contours. after import it does have only layer,x,y attribute and doesn't have Z attribute. how can I provide Z attribute to create a TIN file.
13
votes
2answers
1k 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 ...
8
votes
4answers
1k views

assign and move centroids to their polygons

I m using QGIS 1.8 Lisboa. After calculating the centroids from a polygon shapefile, if some of them lie outside the polygon outlines, I'd like to move them on the polygon they came from. The ...
8
votes
2answers
3k views

How to correctly install QGIS with plugins and GRASS-integration from source?

I'm running a Sabayon GNU/Linux (based on Gentoo) at my home desktop system and I want to install Quantum-GIS. I'm currently using the qgis-1.7.0-package from the repositories. But this is somehow ...
7
votes
1answer
793 views

How to adjust the granularity of a heat map in QGIS?

Not sure I am using the correct terminology here, so I have tried to describe my problem in detail. Please edit as needed. I have a layer of points, a layer of roads and a heat map in a raster layer. ...