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

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3
votes
1answer
160 views

How to connect two line ends in QGIS without resorting to other software?

I have two adjacent (ends meet to make one line) polylines in QGIS. I need to properly connect the two ends of the two sections. I've tried the obvious (and less obvious too) but QGIS won't forget ...
3
votes
1answer
95 views

Referencing Qt UIs external to plugin with python

I'm developing a plugin that sets up a working environment for a user: loading layers (from db), applying styles and several custom designed (Qt) UI files etc. Primary user interaction is in the ...
3
votes
2answers
192 views

Combining MS Office with GIS

I would like to incorporate MS Office into my GIS program. I have been using QGIS and was wondering if this would be possible? I am trying to create a one stop shop for my staff to be able to ...
3
votes
3answers
611 views

Black/white hatching pattern fills in QGis

I am looking to replicate black & white maps in QGis, using hatching patterns and greyscales to indicate different categories of a continuous variable (example below). It is ...
3
votes
1answer
347 views

How to create a x-y scatterplot from attributes in QGIS 2.0?

There are a few old packages that allow the creation of x-y scatter plots from attributes in vector data (Scattergram for 1.7) http://plugins.qgis.org/plugins/scattergrammidentify/ (SPQR for very ...
3
votes
0answers
126 views

How to fetch openlayers layers from pyqgis? [duplicate]

My objective is to fetch maps provided by openLayers, as in openLayers_plugin, from a stand alone python script. I would like to get it superposed to my shp file. As can be read on ...
3
votes
1answer
906 views

How to display an elevation profile and store the DEM elevation back to the KML line?

When I draw a track in Google Earth, for example along a road, I can right-click it to "Show elevation profile", and it displays a 2D plot of distance vs elevation. However, if I save the KML, the ...
3
votes
2answers
1k views

Set feature attribute by name via QGIS python api

I try to set feature attributes by attribute name with this code pr = layer.dataProvider() pr.addAttributes([QgsField("test", QVariant.Int)]) layer.updateFields() for feature in layer.getFeatures(): ...
3
votes
1answer
392 views

How to set drawing style for QgsRasterLayer in QGIS 2?

I am using PyQGIS. In QGIS1, I can use: rlayer.setDrawingStyle ( QgsRasterLayer.PalettedColor ) but In QGIS2, I got some errors. I follow pyqgis developer cookbook, put some demo scripts in ...
3
votes
3answers
488 views

How to calculate peaks in a DEM

How could I extract all peaks from a DEM (large mountainous area)? Peak means something like: a pixel which is sourrounded by other pixels with smaler elevation numbers in a area arround the ...
3
votes
1answer
86 views

How to create a printable data sheet when using edit widget “value realtion” in QGIS 2.0?

I created a spatiaLite Database with a point layer (every point is a tree). Additional I created several tables to fill the columns of the spatial layer with attributes using the editing widget “value ...
3
votes
1answer
422 views

How to create DEM from contours without ArcGIS Spatial Analyst licence?

I'm trying to create a 3d DEM/DTM from a flat contour shapefile which has height data attached to each contour, but I'm not sure how to do this? I've found this post, on creating a dem from contours ...
3
votes
1answer
146 views

Create a band mask based on pixel locations, not in pixel values

I have this image loaded in QGIS, with two possible values for the pixels: 1 = orange, 2 = blue For simplification, assume it represents a province of a country. I want to extract just the part of ...
3
votes
2answers
1k views

How do I create a shapefile of polygons from points in a spreadsheet?

I have a spreadsheet that has 100 different polygons listed with UTM coordinates for the 4 corners of each polygon. I want to turn the spreadsheet into a shapefile with 100 unique objects, 1 for each ...
3
votes
1answer
434 views

KML in QGis with additional Data [closed]

i´ve developed a android app that extracts the exif-information of a photo and creates a KML-file (Placemark) - some additional information like camera-type, focal length,... are stored in the tag ...
3
votes
2answers
471 views

How do I export XY data from QGIS to shapefile?

How do I export XY data from a comma-delimited file to a shapefile using QGIS?
3
votes
2answers
274 views

QGIS 2 problems with Plugins

Rough English (Translated by a user): When trying to access plugins I am told Unable to open the Python console. When I start qgis, the message also shows up but I don't know what it means. ...
3
votes
1answer
277 views

QGIS Arch Linux compilation error

Just pulled QGIS from git and am trying to compile it, here's the relevant error: [ 89%] Building CXX object python/CMakeFiles/python_module_qgis_core.dir/core/sipcorepart3.cpp.o In file included ...
3
votes
3answers
2k views

How to group and count attribute data?

I have a problem with group same data to count it. for example, i want to group same code to one and count them. i can do it when i use MapInfo (Pic 1) but i can't in QGIS. (Pic 2: i can classify ...
3
votes
1answer
214 views

Field Value Mapping QGIS

I am wondering if there is a way to do field value maps that are filtered based on another attribute field? I know how to associate value maps, but not that are connected to another field. I have ...
3
votes
2answers
578 views

How to do a Point to Polygon analysis with multiple variables?

I have a database of almost 10k crimes, which are divided in to 10 categories and plotted on a map I also have a database of 12k addresses, which are also plotted on the map. I aim to perform a ...
3
votes
1answer
417 views

Invert Color Ramp in QGIS

This is a real basic question, but I can't seem to find it. How do I invert the color ramp in QGIS? I am using RdYlGn, but I would rather use GnYlRd. Seems really easy, but I can't seem to find ...
3
votes
2answers
2k views

Are there only two methods of interpolation in QGIS?

I did recently a map of maximum temperature for specific area in Quantum GIS 1.8.0 and its interpolation. However, I was wondering if there are only two method of interpolation, apart from ...
3
votes
5answers
643 views

How can I count overlapping polygons, resulting in a new set of polygons?

I have 100 polygons in a GeoJSON file that partially overlap each other. I would like to produce 100 new polygons as follows: The area covered by any of the original 100. This is their union. The ...
3
votes
1answer
235 views

Divide shapefile

I'm new working with QGIS 1.8.0 and wanted to know if its possible to subdivide a map (shapefile, which is round-like) into small squares but following the outer round contour of the map? I tried with ...
3
votes
1answer
641 views

How to add complex Emergency Symbology (TrueType fonts) to QGIS?

In other packages I would simply ensure the TrueType font (+.ttf) was loaded on the operating system and it would be available for use. QGIS seems to rely on making your own. The symbols I wish to ...
3
votes
5answers
2k views

How to convert KML with tracks to Shapefiles?

I downloaded a KML track from Google Latitude. The service allows to download the tracked route from the user's profile providing a link such as: ...
3
votes
1answer
194 views

Filter contour lines in QGIS

I have a shapefile of contour lines, with an ALTITUDE attribute with the height ASL in metres. The source data is in 0.5m intervals, but I'd like to filter it down so I get contour lines at (for eg.) ...
3
votes
1answer
293 views

Masking/removing polygons from shapefile

I have a shapefile containing the road traffic noise of a city. The shapefile has 5 columns, where 'noise_in' (noise interval) ranging from 1-5 is included. I want to remove/mask the road noise from ...
3
votes
2answers
2k views

How do you change the editing capabilities on a MapInfo .Tab file?

When I load a .Tab file into QGIS I am unable to make changes to it. The information on the MetaData Tab reads the following: "Editing Capabilities of this layer: Add Attributes, Fast Access to ...
3
votes
2answers
148 views

I am unable to draw a shape layer

When I add a new shape layer or want to edit an existing one, nothing is happening. I even don't see the dots where I'm clicking. Maybe the problem is I deleted some layers (by opening the .qgs as a ...
3
votes
2answers
277 views

Layer not aligning after georeferencing using BC Albers

I'm currently having trouble with the georeferencer... after what appears to be successful georeferencing, the map image layer does not align to the vector data. I'm trying to use BC Albers ...
3
votes
1answer
2k views

How to convert jpg file to shapefile? [duplicate]

I am developing a GIS application like this: By now my steps are: I have got a jpg file, 5040 x 8179 dimension. In this map, the roads, rivers, towns etc. are marked. I am using .Net to develop ...
3
votes
1answer
2k views

How to install SciPy for QGIS Standalone [closed]

A number of QGIS plugins require the Python package SciPy to be installed. This package is available using the OSGeo4W package based installer or precompiled for Windows, but is not provided as part ...
3
votes
1answer
2k views

How do I get and install the latest version of QGIS in Ubuntu?

I'd like to get the latest 64-bit dev build of QGIS on my Ubuntu setup. How exactly do I go about it? I assume it's some kind of arcane terminal command...
3
votes
4answers
1k views

What are the advantages either way between GML and Shapefiles?

After a good start many months ago of getting into GIS through QGIS, I had to drop what I was doing and did not touch it for quite some time. I am now able to get back into it and have a need to load ...
3
votes
1answer
629 views

How to get correct scale values?

The scale of my map is wrong, no matter what coordinate system I use in my project. The map and all objects show the correct coordinates but the scale of the map shows nonsense and the measurement ...
3
votes
1answer
172 views

Why can't I edit polygons once they have been saved to MySQL?

I have a simple table with an id field and a polygon field in mySql. Using QGIS I can add new polygons and give them an id. Before saving them I can also edit them. But once a polygon has been saved ...
3
votes
0answers
126 views

Why doesn't Polygonizer copy the line ids to my polygonized shapefile?

I am trying to convert a line shapefile into a polygon shapefile using Polygonizer plugin, and when my new polygons are created all the cells in my id field are "Null", although I have clicked "copy ...
3
votes
1answer
2k views

Import GPX file to QGIS and correct apparent CRS problems

I am using Easy Trails software on an iPhone to output a gpx file of a walk. When I import the file (import vector layer) to QGIS, into a project with OSGB information and the correct CRS for OSGB ...
3
votes
1answer
144 views

Points warped when exporting to shape

I have recently purchased a Trimble GeoXH (used) and have done a few surveys. I have done differential correction in Trimble Pathfinder Office and all points seem fine. When exporting to shape and ...
3
votes
1answer
614 views

Why are the features in my memory layer not displayed?

I am trying to create a memory layer, I followed the directions from the page below but no points appeared on my map. First I tried typing each line into the python console and I also create a plugin ...
3
votes
0answers
101 views

How to digitize 90 degree angles? [duplicate]

Possible Duplicate: How to create polygons with straight lines and right angles in QGIS? In QGIS 1.8 is there a way to digitize buildings etc. with perfect 90-degree angles, Or, edit a ...
3
votes
1answer
2k views

How to export shp to kml?

I already browsed your FAQs, and could not come up with a good answer, I am trying to export shp files to kml to be placed on Google Earth. On a previous version of QGIS it was as simple as right ...
3
votes
0answers
260 views

How to debug Quantum GIS PlugIn Visual Studio DLL?

I develop a Quantum GIS plugin layer using Microsoft Visual studio and placed it in my plugins folder of my customized quantum gis application. I now intend to debug the DLL using Microsoft Studio. ...
3
votes
3answers
8k views

Editing a KML file or converting KML to Editable format with attributes

I'm using QGIS. I'm trying to either edit a .kml file someone else created in Google Earth or convert it to another editable format (like a .shp file). I've read the following threads without really ...
3
votes
1answer
2k views

Is it possible to increase/reduce features proportionally?

Is it possible with QGIS to increase or reduce features (polygons or lines already drawn) proportionally? Preventing me to redraw several times new polygons :) See picture above: Making it possible ...
3
votes
1answer
632 views

QGIS custom CRS for map of manufacturing shop floor

I'm working on a web app that shows a map of a manufacturing plant's shop floor. I've built it in Inkscape and QGIS, but when I try to load it into Tilemill, I get a CRS error. Specifically, it ...
3
votes
2answers
754 views

How to densify a polyline according to a specific length? [duplicate]

Possible Duplicate: Add vertices to lines I am using QGis 1.8.0 I would like to densify a polilyne according to a particular length of segment (ex. 200 m). I know it is possible with other ...
3
votes
1answer
1k views

How can I get my Qgis area calculations in metres rather than degrees? My shapefiles are projected using WGS 1984 UTM fuseau 35 Sud

I am using Qgis 1.7.4 to calculate the area of polygons. My shapefiles have been projected using the coordinate system WGS 1984 UTM fuseau 35 Sud, but my area calculations are still displayed in ...