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

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9
votes
2answers
10k views

How to create a new layer from overlap between two layers?

I'm new to desktop GIS, and will try to ask while lacking the proper terms from the GIS lingo: If QGIS was like Photoshop I would like to make a selection from one layer, and then match that ...
5
votes
4answers
323 views

How to Unsplit/Dissolve multiple touching lines in Stream Network?

I am trying to dissolve multiple lines for stream networks into individual features. The dataset contains many stream networks so a complete dissolve of the whole dataset wont do as I would like to ...
4
votes
1answer
1k views

How to style a layer from console?

I am new to the QGIS python console. I am trying to load a raster layer from the console, set the crs and a specific style from a qml file. layerPath = os.path.join(raster_dir,raster_name) fileInfo = ...
31
votes
3answers
10k views

Visualising WKT geometry string in QGIS

A very simple question: Is there a simple tool in QGIS to graphically visualise geometry formatted as text? Example geometry: "POLYGON((571178 6337246,571178 6402217,598061 6402217,598061 ...
7
votes
2answers
4k views

How to calculate Network Service Areas in QGIS?

Is there any way in QGIS to apply service area buffers e.g if I have a point on a map I wish to show the service coverage of 1 mile, 2 mile, 3 mile, breaks using the road network?
21
votes
5answers
5k views

Is there any model builder in QGIS or other open source GIS?

Like the ModelBuilder of ArcGIS for Desktop to run simultaneous geoprocessing tools, is there any model builder available in QGIS or any other open source GIS software?
17
votes
9answers
27k views

How to install QGIS on Ubuntu 12.04?

Has anyone had any luck with getting QGIS working on Ubuntu 12.04? I have tried the stable and unstable versions and with not luck. I also get the following: "Some packages could not be installed. ...
14
votes
3answers
1k views

Is there an automatic function in QGIS to package all files in a project for transferability?

In my project, I use a lot of geodata from different directories. Now I want to give the QGIS project to a colleague (eg on a CD). Is it possible to copy the shapes from different directories ...
10
votes
2answers
2k views

How to compute parameters for QGIS Affine transformation?

I have a vector floorplan (DXF) that I've added to a blank project in QGIS using the Dxf2Shp plugin. I've been reading tutorials and StackExchange threads, but I can't seem to find out how to ...
8
votes
1answer
408 views

How to automatically populate fields instantly?

I am looking to create an attribute table where the first field is a drop-down menu (I have achieved this by using the 'value map' edit widget), but I'm struggling to find a method for the next part; ...
7
votes
2answers
7k views

Is there QGIS plugin to allow 3d visualisation of geological borehole data similar to functionality of Target for ArcGIS?

I'm very new to QGIS, I have started using it as my new company is not willing to pay for ArcGIS and Target at this stage so I'm hoping QGIS can substitute not just in the interim but for good. What ...
20
votes
2answers
24k views

How to access file geodatabase in Qgis? [duplicate]

How does one access data from an Esri file geodatabase in Quantum GIS? I've seen snippets of conversation that indicate it's possible with qgis 1.7+ and gdal 1.9+ but no clear recipe. I recognize ...
8
votes
1answer
4k views

How to reproject a raster file in QGIS with datum transformation?

I want to reproject a tiff raster file from projection A (ETRS89/UTM Zone 32) to projection B (DHDN/Gauss-Kruger zone 2). The two projections have a different datum so I have to use a datum ...
15
votes
9answers
11k views

How do I create a shapefile showing footprints of Rasters?

I have around 1,000 satellite images in tiff format, and I want to create a shapefile which will serve as an index to the rasters. This is something similar to a raster catalog, but I do not want to ...
9
votes
1answer
3k views

Using PostgreSQL with QGIS and ArcGIS?

Is it possible to use PostgreSQL with QGIS and ArcGIS? i.e. one database for different clients. Is it anything that I have worry or any problems to use the DBMS from two different software? I know ...
7
votes
1answer
3k views

Getting tabular statistics from table using QGIS?

Are there QGIS tools that will allow users to get tabular statistics from their table? I kind of expected I would be able to just open the table, select the field I was interested in, right-click on ...
4
votes
4answers
6k views

Is there a Rotate Tool in QGIS?

I can see the move tool. But coming across versions, i did not see any Rotate tool in Quantum GIS. As a hardcore feature editor myself, i have found it rather difficult. Am i missing something ...
13
votes
4answers
11k views

How to determine the centroid of polygons?

I have a polygon vector and I want to quickly attain the centroid of this polygon for insertion in a text document. I am working with QGIS. I searched through other questions and although some are ...
7
votes
3answers
5k views

Why don't my Shapefiles and OSM data overlap in Quantum GIS?

So I'm pretty new to GIS, and I'm working on a mapping project using data for Vancouver, Canada. I want to combine Open Street Map data along with data provided by the City of Vancouver. But the City ...
6
votes
2answers
787 views

Ortho Projection produces artifacts

I`m trying to create a sphere-like view using qgis and the "world from space"-projection http://spatialreference.org/ref/sr-org/6980/ (essentialy an ortho-projection). ArcGIS wraps the shapes ...
5
votes
3answers
2k views

Finding centrelines from polygons?

I was wondering if there is a way to create centre lines from polygons in QGIS? I have a polygon layer, but ideally need the centrelines as a separate file. Thanks, Alan
4
votes
1answer
278 views

Where to report QGIS and QGIS-Plugin bugs?

I often find bugs in Qgis and its Plugins. I would like to ask about this on the internet but I do not seem to find the proper place to address this issue. Are there any instructions?
7
votes
3answers
704 views

How to create an OD road distance matrix in QGIS?

I'm looking for the steps required to produce an origin-destination (OD) cost matrix. What I'm looking for is a matrix of road distances. The distance matrix tool only produces euclidian distances. ...
7
votes
1answer
12k views

Adding Layerfiles (.lyr) to QGIS?

At college we use ArcGIS Desktop 10, but that does not function on my Mac so I have QGIS there instead. I want to do my exercises with QGIS, but we use .lyr files with ArcGIS Desktop, and they are ...
6
votes
3answers
19k views

How to get the coordinates in Lat/long from a point layer?

Sorry for asking this basic question, but I couldn't get the solution from the previous answers. I need to extract the Lat/long coordinates of the centroids of districts. My QGIS project SCR and the ...
5
votes
1answer
803 views
4
votes
1answer
236 views

How to horizontally align irregularly shaped point symbol to vector layer in QGIS?

Fairly new to QGIS and searching a method to graphically align my point symbols in the direction of the vector. The symbol represents a water valve in an irregular shape in close proximity to a vector ...
4
votes
2answers
3k views

Workflow for creating line features between two coordinate pairs in QGIS

I have a table of stream reaches with xy coordinates for their respective tops and bottoms. I'd like to convert the table to a feature, using the xy coordinates as the endpoints of the line. Any ...
5
votes
1answer
1k views

How do I clip OSM basemap with a polygon?

I've created a map in qgis 2.0. The map uses the OpenLayers plug-in to add the OSM layer as a basemap. I would like to restrict the basemap to be visible only inside a given polygon defined in a ...
5
votes
2answers
4k views

How to display both scalebar in kilometers and grid in lat/long degrees in Quantum GIS 1.8 Composer?

Also, how to display both scalebar in kilometers and both lat/long degrees and northings/eastings in QGIS 1.8 Composer? Layer is projected to UTM. Thank you.
5
votes
1answer
887 views

Identify Polygons on raster image

I have OS street view mapping as raster images. Is it possible (without the obvious of tracing each dwelling) to identify all polygons on each tile. To clarify, My ultimate aim is to produce a ...
4
votes
2answers
6k views

Which hardware configuration is necessary for QGIS?

What kind of hardware is necessary to run QGIS on Win XP? Closely related: Specifications for GIS desktop hardware
3
votes
1answer
319 views

QGIS display does not reflect projection

I have slight experience with ArcGIS, but am new to QGIS. I'm trying to set the projection of my map, and I understand that this is done by altering the CRS (coordinate reference system) of each ...
1
vote
1answer
676 views

How to go with…somewhat complex geological maps in QGIS?

Just a follow-up to this question QGIS: Line to polygon conversion. Not sure do i have to continue there itself... We are currently digitizing a geological map...which has 36 features in total. Some ...
1
vote
3answers
4k views

How to create points based on the distance and bearing from a survey point?

I am plotting witness tree data to calculate pre-settlement tree density. I have a shapefile with points along section lines (square miles) at each half mile. I am making another table that contains ...
11
votes
1answer
3k views

How to add labels outside of features?

I'm trying to achieve this kind of labeling using QGIS. Apparently, it doesn't seem to be easily supported. Would you have an idea for a workaround ? I managed to have circled text using ...
21
votes
3answers
5k views

How can I calculate the average width of a polygon?

I'm interested in examining the average width of a polygon that represents the road surface. I also have the road centerline as a vector (which is sometimes not exactly in the center). In this example ...
10
votes
3answers
636 views

How can I parallelise embarrassingly parallel GIS operations in QGIS python?

A common requirement in GIS is to apply a processing tool to a number of files or apply a process for a number of features in one file to another file. Much of these operations are embarrassingly ...
24
votes
5answers
2k views

How to generalize a polygon file and maintain topology in QGIS?

I have a polygon Shapefile, which I need to generalize. How can I generalize the poligons and ensure that there are no topological errors like "slivers". I already tried: Vector -> Geometry Tools ...
12
votes
4answers
3k views

How to place elevation numbers on contours with uphill orientation and position?

I want to orient my elevation labels uphill. Is that possible? I'm currently using the labeling tool from QGIS (not that one in layer settings). I want the labels curved and uphill oriented (and I ...
6
votes
2answers
3k views

What are valid values for “data defined” labeling settings?

I'm using QGIS 1.8. I'd like to customize label features on an existing shapefile using the new label engine and it's "data defined settings" option. I'd like to know what the attribute table field ...
10
votes
3answers
6k views

How to create polygons with straight lines and right angles in QGIS?

I am running QGIS 1.7.0 on Mac OS X 10.6.8. When creating a polygon, how do I do it so that the lines are straight (90, 0 degrees, etc.) and when I create corners they can be right angles? For ...
20
votes
8answers
25k views

Can QGIS open KMZ files?

I know I can add KML files once I have unzipped the KMZ files, but is there a way to open KMZ files directly? When I try to open a kmz file on QGIS 1.8.0 on Windows XP, through the all files filter, ...
11
votes
4answers
16k views

Is there a SVG symbol library for qgis?

Im currently using default simple symbol capabilities or dingbat fonts for point objects. Is there maybe a SVG symbol library for qgis that is a bit more extensive than that which is included? I've ...
8
votes
1answer
4k views

How to fill gaps in SLC-Off Landsat 7 ETM+ Images with QGIS?

Explanation of the problem: On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had ...
7
votes
1answer
9k views

How to select features within a polygon from another layer?

I'm using QGIS 1.8 with a PostGIS database and I have three postgis-layer in qgis a lines layer, a points layer and a polygon layer. What I'm trying to do is to select a polygon in the polygon layer ...
5
votes
2answers
4k views

How to install QGIS on Centos 6?

I'm new on this; I really tried a lot before ask.. but nothing works. I did all that the qgis page says. Install ELGIS. after that i investigate and tried diferents comands.. but nothing works..the ...
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?
12
votes
5answers
5k views

Is it possible to connect to ArcSDE using QuantumGIS?

Is anyone aware of any plugins, or any other way to connect and view data from an ArcSDE database in Quantum GIS desktop?
10
votes
2answers
4k views

Running QGis from flash drive

How can I setup a portable QGis to run from a flash drive / USB-Stick? In the userguide for QGis 1.7 Wroclaw there is only mentioned the option of "--configpath". But to me it is not clear how to deal ...