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

learn more… | top users | synonyms (1)

1
vote
0answers
108 views

How to run PostgreSQL stored procedures from QGIS? [closed]

I'm trying to figure out if it's possible to run a stored procedure in a Postgres database from QGIS, more specifically I would like to do this from within a python plugin. In this case I'm trying to ...
1
vote
2answers
751 views

How can I create a merged buffer in QGIS then count points that fall within it

I have a QGIS plan which shows ponds (as points in a shape file with an OS tile as a background) within a survey area. I need to calculate the total number of ponds within 1 km of each of the on-site ...
2
votes
2answers
328 views

How to use ggplot with Processing in QGIS 2.0?

I'm trying to use R scripts within QGIS thanks to Processing. There are some example scripts available and I achieved to plots different columns of the attribute table (with the plot built-in ...
0
votes
0answers
108 views

Can I simplify polygons in QGIS by Size?

Just wondering if it's possible in QGIS to simplify polygons based on size? I've done it many times using the tolerance level to reduce the overall size however in this case each polygon cannot be ...
0
votes
1answer
77 views

Raster to Surface

I have a raster and I have been asked to modify some pixel values in it. Is there an open source way to do this? I would guess that I have to create a 3d surface, then manipulate the surface, then ...
3
votes
1answer
589 views

How to build a confusion matrix for image classification using SAGA or QGIS?

I did a supervised classification of a Landsat image subset using my training data polygons. I used SAGA GIS for that and everything worked out fine. Now I am stuck since I have no clue how to ...
2
votes
3answers
213 views

Generating a polygon tile index from multiple vector datasets

OK. well this is silly, in that there is no way it should be as difficult as it has been for me to find information regarding how to generate a polygon tile index from multiple vector (contour) tiles. ...
0
votes
1answer
56 views

How can i create single feature fwith Combining Selected feature qgis?

I am trying to create a single Qgsfeature from the Combination of selected features in Pyqgis. Currently i create the feature using a loop over selected features and combine them 1 by 1. but this ...
0
votes
2answers
349 views

Is it possible to set a reference scale in QGIS?

It's a little tricky to pick label and feature styles (line thickness, colours, etc) in the map canvas because they don't reflect what I would see in my print composer which is at a different scale ...
2
votes
0answers
733 views

Kriging with SAGA and QGIS [duplicate]

I have the "processing" toolbox installed on QGIS2 and it would appear to give me access to the SAGA variogram tools and and kriging tools. What I am missing and what I can't find via Google either, ...
0
votes
0answers
368 views

RasterXSize from gdal Nonetype error

I have this code to create a raster file in python: fileInf = QFileInfo(userIntervals) baseNam = fileInf.baseName() rlay = QgsRasterLayer(userIntervals, baseNam) gdalRast = ...
0
votes
0answers
258 views

How Can i create a Vector layer from selected features qgis

In my qgis plugin i select dynamically features from a Vector layer. and currently i create a new layer from selection on combining all feature into a new feature: theField = QgsField self.theString ...
2
votes
0answers
84 views

Distribute QGis plugin which depends on certain Python packages

I developed a plugin for Qgis which depends on some Python packages. On Linux and Mac, this is not really a problem because I can easily install them with the system pip command. Windows is another ...
1
vote
2answers
218 views

Saving a gml layer does not change coordinates

I am trying to export a gml layer to geojson with lat/lng as the preferred coordinate system. So what I did was a 'save as' on the layer with selected CRS: 'IGNF: WGS84G'. Now I was hoping it ...
3
votes
3answers
227 views

Can Mapnik 2.2 and Qgis 2.0.1 be installed together?

I'm using LM15 (== Ubuntu 13.04 Raring) with the Launchpad repos for Qgis Unstable 2.0.1 and Mapnik 2.2.0. Quantum wants libgdal1h; Mapnik wants libgdal1. As soon as I install one, the other gets ...
2
votes
1answer
124 views

How to control road labels in Atlas QGIS 2.0?

I'm producing map books for our water assets. These books are taken out into the field by the workers so they can see where various 'things' are for the work they need to undertake. There are over 200 ...
1
vote
2answers
811 views

Calculate area covered by a particular raster layer within polygons in QGIS

I am trying to extract information on vegetation cover within a set radius of point locations (my sites). I have succeeded in creating a new vector layer of circles with a 5 km radius around my sites. ...
1
vote
2answers
98 views

How to convert small overlaping polygon features to inner ring in QGIS

I have a polygon vector layer with overlapping features (like below) and I would like to convert the features that are fully contained inside the bigger polygons (ie feature 2 and 4 below) into inner ...
3
votes
1answer
490 views

Upgrade QGIS from 1.8 Lisboa to 2.0?

I have QGIS 1.8 and I want to upgrade to 2.0 Dufour... Should I just download the file and launch the installation? Or first uninstall 1.8? Thank you! Lily
0
votes
1answer
146 views

How to create shapefiles with z coordinate with QGIS

I'm working with QGIS, and I want to create a shapefile with the elevation coordinate, I can't find something similar to what I was used to do in Arcgis, can you help me? Thanks for your help Luís
5
votes
1answer
654 views

Adding Multiple Maps in QGIS Composer?

I am working with QGIS Composer 2.0 and I would like to add a second map. What I would like to do is to have a main map that takes up the majority of the print area. This map, Main Map, will have ...
0
votes
0answers
166 views

how do I add attribute features to an attribute table which already exists?

Using Verson 2.0, downloaded as normal. I have an ESRI shapefile of my road map for 2006. I have a paper map of roads for 1969. I want to see what roads have been built between 1969 and 2006 (none ...
1
vote
1answer
508 views

Arc ASCII Grid output problem in QGIS 2.0

I used to convert tif files to ascii in Qgis 1.8 using gdal translate without having any problems with the output i.e. I have the normal heading and values. When I upgraded to 2.0 I started to get the ...
0
votes
2answers
450 views

Developing standalone gis applications using pyqgis

I am trying to develop a standalone application using pyqgis but I have no clue on where to start and where to write the code to make it happen so if anyone can provide me a tutorial to getting ...
0
votes
1answer
226 views

Problems with Polygon Reshape Feature

I'm new in this forum, and i need some help with my project. I've created a polygon and closed my project, after opening the project again, i can't use the Reshape Feature tool in that specific ...
1
vote
2answers
374 views

On the fly transformation From WGS84 to NAD27 with proj4 code

I want to use this proj4 code: +proj=utm +zone=19 +ellps=WGS84 +toclrk66=-3,142,183,0,0,0,0 +units=m +no_defs or this one +proj=utm +zone=19 +ellps=WGS84 +tonad27=-3,142,183,0,0,0,0 +units=m +no_defs ...
2
votes
3answers
720 views

How to remove vertices or lines within a polygon?

I have transformed a *.dxf-file into a polygon shape-file. In many of the polygons i have lines whicht do not belong there but i can not delete them as i normally delete vertices on polygons by ...
3
votes
0answers
107 views

Creating a new raster based on pixel value of original raster using raster calculator but new layer is not evident [closed]

I am trying to create a new raster based on a current raster (w001001 - NVIS) which has one paletted band, with palette values ranging from 1 to 29, with each palette/value representing a vegetation ...
1
vote
2answers
474 views

TIFF/Raster to Point shapefile question

Apologies in advance if this question is incredibly basic, but I've been googling around and I just don't know where to start. I've downloaded some nighttime luminosity data from NASA, and the data ...
1
vote
3answers
192 views

trouble installing the qgis2kml plugin (or, how to install plugins not available in the Plugin Manager from source)

I'm trying to install the qgis2kml plugin for qgis. Its not showing up in the Plugin Manager search and the only qgis "repositories" I can find are websites for downloading source code. Which is ...
3
votes
1answer
139 views

Tornado Data Points: Linking 2 Points in QGIS on the Same Row

So I've got these tornado .csv files that have two latitude & longitude entries with the left-most in the table being the beginning point and the right-most being the ending point of the tornado, ...
0
votes
1answer
94 views

How can i stop rendering Qgis

In my python plugin ,i select features from a vector layer dynamically using a loop and executing : VectorLayer.select(feature.id()) when i start the loop, the selection become very slow because ...
4
votes
1answer
254 views

Debugging errors of SAGA interpolation algorithms in QGIS 2.0 Processing

I encounter recurrent problems with the geoalgorithms that perform interpolations. No matter technique I use I end with the following errors. As state in OGR tab QGIS is unable to open a file in C ...
2
votes
2answers
63 views

Join by location on Qgis when target layer has multiple layer

I posted here a while ago about spatial joins. I have a huge dataset (20,000?) of bird and mammal ranges. I have another dataset of all the countries. In qgis, I was attempting to link the two ...
2
votes
2answers
65 views

How can I display a spatialLite view in a custom data sheet with print composer

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 ...
2
votes
1answer
246 views

How do I access QGIS program settings programmatically?

I am trying to temporarily enable the option in QGIS using PyQt4 to suppress the attribute dialog popup after a feature is added. I found an example in the cookbook but it doesn't indicate how to get ...
2
votes
2answers
1k views

How to cut a line feature in QGIS 2.0?

I want to shorten a feature (a polyline representing a road) in QGIS 2.0. I tried the 'cut features'-tool that look like a pair of scissors. First I chose the right layer, and then clicked 'Toggle'. ...
1
vote
0answers
260 views

Display plugin icon

I'm unable to setup the display of the toolbar icon for a plugin in QGIS 2.0. I have compiled the "resources.qrc" with the correct path and filename, and checked possible spelling errors in the code. ...
1
vote
1answer
455 views

Creating a custom attribute table in qgis print composer

is it possible to arrange header and content of an inserted attribute table in qgis print composer? I want to create a custom datasheet with a small map and listed feature information as follows: I ...
1
vote
1answer
588 views

How to apply svg symbols as point markers in QGIS 2.0

I must be overlooking something obvious! I've just downloaded and launched QGIS 2.0. I'm trying to edit a layer's symbol markers to use a more descriptive icon. Opening layer properties and then ...
3
votes
1answer
1k views

how to fix greyed out edit button

I created a QGIS map, which I was able to edit (right click on layer and select toggle edit, or use button in tool bar). Having returned to work on the plan, most layers now have this button greyed ...
2
votes
1answer
157 views

What prevents GRASS and SAGA integration into QGIS when users aren't administrators?

Windows version of QGIS 2.0 using the stand alone installer. I have been able to tie up the functionality using the Options and Configurations settings in the Processing menu. This works fine in a ...
0
votes
0answers
84 views

QGIS 2.0 Performance issue when selecting by location on a complex dataset

I have an issue when I use the select by location tool in QGIS 2.0 to select points within a very complex polygon. It is flood data, so has something like 350,000 nodes and is generated as a single ...
0
votes
1answer
68 views

Dissolving polygons closers than 50m into a single shape QGIS

I’m new with GIS (coming from a CAD background) and using QGIS 2.0.1. I have a very detailed map of urban fabric in a UK region, to the detail of individual buildings. I want to simplify that map by ...
1
vote
2answers
610 views

Alternative repository for QGIS 2.0 plugins

Is there any alternative to the official repository for plugins of Qgis 2.0. I prefer to be a tested and trusted. EDIT: I found a source which refers to OpenGeo Explorer For more info: ...
4
votes
1answer
317 views

lookup forms in QGIS

Bit of an open question but.... Is it possible to design a form in qt designer that will be used as a form against a qgis layer but interacts with a different table in postgres/postgis as a lookup ...
0
votes
1answer
100 views

error in overlapping layers in QGIS

I created two tables with PostGIS, within which I have inserted a shapefile of an Italian region (Apulia) in the first, and the coordinates in the second table. In both tables are set with the ...
0
votes
0answers
101 views

Point features disappear when moved using QGIS 2.0

When I move, either by the node or the move function, a feature symbol on the map canvas, it simply disappears, not just the label, the whole thing. CTRL-Z brings it back. I'm using a MAC OS-X. I've ...
2
votes
4answers
699 views

Merge large number of polygons using QGIS

I have a series of polygons that are the output of another GIS program - I need to merge the polygons into a single polygon. I have tried a couple of different methods with no luck. I have tried to ...
5
votes
2answers
748 views

How to define leaders to a label in QGIS 2

In QGIS 1.8 and 1.9 I used a plugin called Easy Labels to develop leader lines that would be saved as a memory layer. I have not been able to replicate this with QGIS 2.0, I cant even find the Easy ...