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

learn more… | top users | synonyms (1)

0
votes
0answers
14 views

Why nodes may link to remote ones?

I've noticed that sometimes when creating or editing lines or polygons some nodes may connect spontaneously with nodes in remote areas of the map, creating geometry problems. Why does it happen? Is ...
0
votes
0answers
9 views

QGIS: geometry calc fails

I'm trying to perform a simple calculation using QGIS but there must be some sort of environment variable setting that my process exceeds. Any ideas? Vector -> Geometry Tools -> Polygon Centroid
2
votes
1answer
48 views

Layer properties dialog in my QGIS plugin

I am developing a plugin which should display some information like geometry of the layer, feature count etc. Now those are currently displayed in QMessageBox.information. I want it to be displayed ...
0
votes
2answers
57 views

Connect to postgres localhost in QGIS

I am firly new to actively work with databases. I wanted to try out some stuff on my home computer where I have installed pgadmin and postgres previously. I can connect to my localhost in pgadmin but ...
3
votes
3answers
111 views

Separate a string value in two integers in QGIS

My problem is the following. I have a huge dataset of forest stands. All the information are separated but in many cases the stands have different age and this is marked in one attribute for example ...
0
votes
1answer
21 views

MySQL primary key column not visible in QGIS 2.6

I've tried adding a vector from Mysql table (Mysql 5.1, MyISAM) to QGIS 2.6. All columns are visible except Primary key column(s). Could anyone confirm this behaviour? Could we consider it a bug?
1
vote
0answers
31 views

Extracting the contents of a Google-KML file

I finally found all the datasets I could possibly need from http://globe.six.nsw.gov.au/ ...but a few hours later I'm not sure if it's possible to access this data into QGIS. I've tried MapWindow ...
0
votes
0answers
15 views

open pictures on server using a shapefile in QGIS with the filepath as an attribute

For my work I need to open geo-tagged pictures of the forest, with known location stored in a point shapefile by clicking in QGIS on the file path in the attribute table of the shapefile. This all ...
2
votes
0answers
31 views

How to union linestring data distributed on multiple layers?

I have four shapefiles. Each contains a linestring as shown in the image. Each shapefile is represented as its own layer in QGIS. I would like to union these linestrings into one polygon which ...
1
vote
1answer
33 views

Select polygons that contains points in a separate shp file

I am a very new QGIS user and have years of experience using the basic functions of ARCGIS. I am having trouble using the select by location feature in QGIS. I have a point layer with locations of a ...
0
votes
2answers
38 views

Mean values of points within a polygon layer

I have 2 shape files (1x points and 1x polygons). The points have different values (soil sampling results). What I want to do is to calculate the mean values of the points inside the different ...
0
votes
2answers
46 views

Why are my transparent png tiles showing up weirdly in QGIS?

I have Ubuntu 14.04 running QGIS 2.6. I'm loading a raster layer, but the transparent PNG shows up poorly. The black lines along roads aren't showing up and the anti-aliasing looks off. I'm thinking ...
1
vote
0answers
34 views

What is the best tool to get block structure from parcel data?

I am trying to analyze the urban form of a city. I don't have the polygon file for streets, so I must derive block structure from parcel data (see image below). What is the best tool to accomplish ...
0
votes
0answers
11 views

Why is a layer not rendering?

I have a problem with a Spatialite layer which is not rendering. I've deleted a node and now it only renders at scales higher than 1:20000. Checking the geometry it throws these errors: 57,ring 1 ...
1
vote
1answer
17 views

Saga:processing resample extent in python editor QGIS

I would like to resample many geotiff layers to another geotiff layer's extent and pixel size. For this I would like to use the QGIS python console (editor). When I run my script it raises the ...
0
votes
0answers
39 views

How to resolve warning messages from standalone script?

The standalone script, loaded from OSGeo4W Shell and copied below, follows a set of steps: Create grid with cells length/width at 200m Clip a polygon layer onto the grid Use Distance to nearest hub ...
1
vote
1answer
40 views

Is it possible to add multiple labels for each element of a layer?

I want to add different labels for the elements of a layer. Example: One label with the number inside the marker. Another label above the marker with the name of the element, different typography ...
3
votes
2answers
67 views

QGIS (2.4) keeps caching old Python code

I'm fiddling around with a piece of python code to use with form validation. It works fine, but the real problem is that QGIS refuses to acknowledge the changes I make in the script. Here's what I ...
1
vote
1answer
61 views

How to deactivate my custom tool by pressing the Escape key using PyQGIS?

I'm developing a QGIS plugin and I have created a custom tool. Once the process is over, if the user presses the ESCAPE key, I want my custom tool not to trigger mouse events on the map anymore. How ...
2
votes
2answers
67 views

How to disolve lines from same layer?

How can I dissolve lines from the same layer so there are no borders in the junction? For example, a crossroad shouldn't have any border (not as seen in the picture). Can you help?
1
vote
1answer
53 views

Overlapping polygons in the same layer

I am working in QGIS on a vector layer where areas are classified using an attribute "typo". The problem I'm encountering is that many polygons are duplicated or overlapping, with the result that some ...
1
vote
1answer
31 views

Continuous raster legend in QGIS map composer

Is it possible to make continuous raster legend in QGIS? Something like in ArcGIS???
1
vote
1answer
26 views

Unable to find a specific GRASS add-on in QGIS

I would like to use the r.xtent add-on made for GRASS GIS (http://svn.osgeo.org/grass/grass-addons/grass6/raster/r.xtent/description.html) in QGIS using the GRASS plugin, but I can't seem to find it. ...
1
vote
1answer
26 views

How to calculate the sum of virtual fields

I have a set of data on track creation in a large forest, my job is to explore the cost implications of various layouts. I have a virtual field for track length and one which multiplies length by cost ...
0
votes
0answers
22 views

Plot delivery routes over the OSM network (snapping to OSM vector layer)

I have a question with regards to snapping lines to the OSM road network. My goal is to show several delivery routes over the OSM road network. I have done the following: - Plot all addresses on the ...
2
votes
1answer
68 views

How to iterate over features and abort iteration with keypress in PyQGIS?

I would like to run a loop with PyQGIS, it should wait for the user to press a key either SpaceBar or Escape to continue. canvas = qgis.utils.iface.mapCanvas() aLayer = canvas.currentLayer() feat = ...
0
votes
0answers
12 views

How to snap already digitized polygons in different layers using QGIS?

As a newbie, I have digitized a lot of polygons without snapping them. Is there any way that I can add snapping to them aftervards? They are in different layers?
0
votes
0answers
23 views

qgis action html

I'm a newbie in QGIS and python. I made a QGIS Action with parameters [% attributename %] that works fine. import urllib2 req = ...
1
vote
0answers
37 views

Distance Matrix QGIS

I'm trying to get a distance matrix though QGIS, I have two different point layers to run the distance matrix and have input and target layers correct, output matrix type is Linear(n*k x 3) Use only ...
1
vote
1answer
39 views

Adding PostGIS raster to QGIS via database manager

When I attempt to add a PostGIS raster to QGIS I get a GDAL error saying I need to set PGHOST. I have set PGHOST with export PGHOST=localhost but still get the error. How can I resolve this ...
1
vote
1answer
30 views

Globcover 2009v2.3 Legend Qgis

How can I add a legend to a raster to the Globcover land cover dataset in QGIS without plugins? The data can be found here http://due.esrin.esa.int/globcover/ Unfortunately, as far as I know, QGIS ...
1
vote
1answer
31 views

Multiply whole column with the field calculator in QGIS

I have a layer with the field size. I did some mistake with the value and now I need the values multiplied by 16. But instead of going through 500 lines and recalculating them I would like QGIS to do ...
1
vote
1answer
38 views

How does fTools' Distance Matrix compute the distance and in what units?

I am new to GIS in general, and QGIS in particular. I am trying to find information about fTools' Distance Matrix function in QGIS, but am having trouble finding documentation…I managed to make a ...
0
votes
2answers
25 views

Exporting QGIS polygon shapefiles to Trimble Juno or similar

I am considering buying a Trimble Juno or similar hand-held field computer to assist with vegetation survey. My main need is to be able to see on it shapefile polygons drawn on my home PC in QGIS. I ...
1
vote
2answers
35 views

Splitting polgons in QGIS produces topology errors

I am trying to split existing polygons but when I do, gaps and overlaps are created between the polygon I am cutting and adjacent polygons. I have snapping switched on and have enabled topological ...
0
votes
0answers
18 views

QGIS opening file - Very slow on POSTGIS databse with many layers

When opening a qgis file with many layers (20 or so) it takes +5 minutes to load. All the layers come from a single PostGis database. When looking into the server logs, i see that there are many ...
1
vote
1answer
68 views

How to link my QGIS plugin main class to mouse events from a custom Tool?

I Have two files one is mouseevent.py and the other one main.py. class MouseClick(QgsMapTool): canvasDoubleClicked = QtCore.pyqtSignal(object, object) def __init__(self, ...
2
votes
1answer
68 views

Generate new geometric network from intersection between curent network and polygons

Ok I've been battling this one for a little while. I have generated a stream network using the "Strea Reach and Watershed" tool from the TauDEM toolbox. Within the stream reach dataset there are ...
0
votes
1answer
55 views

export to GeoJSON coordinates in the reverse order

This question has been asked before, but I don't understand how to use the answer given by cengel. I want to make a GeoJSON file with lat long coords, not the default of long lat coords. I have a ...
0
votes
0answers
10 views

Integrating numeric scales into a text or HTML box in QGIS print composer.

I am trying to embed the scale of a map in the print composer expression builder or HTML frame. Effectively the value of the scale in the map item properties would come through into the text and be ...
1
vote
2answers
134 views

Installing QGIS 2.6.1 on Ubuntu 14.04

First I am relatively new to linux particularly Ubuntu 14.04 so if you intend to help me, just indicate the exact commands (step-by-step) that i need to type to get QGIS 2.6.1 Installed I have tried ...
1
vote
1answer
23 views

What's the letter and word spacing unit in QGIS labeling?

I just want to know if letter and word spacing, in qgis labeling, are expressed in points, and if the value its absolute or relative to the font. I have searched a lot, but I can't find any ...
2
votes
2answers
67 views

great circles in QGIS and export in 3857 webmap

My plan is to visualize great circles in a leaflet webmap. So coming from this great postgis article and R version I thought it would work like this in QGIS: create line from two points, store ...
1
vote
0answers
21 views

“mapinfo qgis style converter” : error message

I would like convert a big point layer from .Tab toward .QML thanks to the plugin called "mapinfo qgis style converter" . The symbology of my layer is quite complexe (variables of coulours, shape, ...
0
votes
1answer
33 views

How to delete a shapefile from a directory using QGIS?

I am using the following code to clip a shape file using processing tools via Python and would like to delete the clipped file from the directory. Here is my code. from PyQt4.QtCore import * from ...
1
vote
0answers
39 views

qgis-bin.exe has stopped working after changing symbol selector?

i am having troubles with QGIS 2.6.1. It crashes when i try to change the symbol selector within each vector layer. If it doesnt crash it seems that the changes i have made in symbol selector do not ...
0
votes
0answers
25 views

Contour Creation for Export to CAD including z values using QGIS

I have LiDAR tiles for my appropriate areas where I need to extract the contour and relevant height information for use in flood studies. I am able to draw out the contours from the data, however ...
1
vote
0answers
15 views

How to fix the links clipped by an unconnected area in QGIS?

I'm trying to clip my target shape file with a given example area. The given example area looks like the following pic: And there is a river separating two areas. However there are links ...
0
votes
0answers
26 views

Windows 8.1, surveysegments, system.data problem

I Have a c# project written back in 2009, trying to bring into the windows store universal app (windows 8.1 VS 2013, c#). The old project has references to Microsoft.sql.server.types ...
0
votes
0answers
15 views

Creating Pie Chart within buffer using QGIS?

I am working on a project which is about Habitat analysis for Polecat using QGIS in Schleswig-Holstein. summary of project: Polecat vehicle collision occurs frequently in Schleswig-Holstein. This ...