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

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3
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1answer
579 views

How can I iterate over several layers and run a process using PyQGIS?

I am trying to find road intersections within each of my memory Polyline layers (which are named road_layer_i for i in (0-99)) so this is what I tried: import processing self=qgis.utils layers = ...
1
vote
1answer
127 views

QGIS Composer Big Red X

I am working with QGIS version 2.01. I created a print composer to export the map with legend, scale bar and title to an image or pdf. When I opened my QGIS project again and went to my print ...
4
votes
1answer
309 views

MapInfo “Boundary Select”, “Sum Attributes”, and “Update Column by Spatial Query” in QGIS? [closed]

I´m a MapInfo user, I´ve gone over to QGIS and it´s got a lot going for it, except for some "missing" simple features from MapInfo I just can´t do without.... MapInfo Boundary Select - spatial query ...
1
vote
1answer
138 views

Updating QGIS version through OSGEO4W - Unable to get setup.ini

I want to update the QGIS versions that I am using through OSGEO4W. I am currently running QGIS 2.0.1-Dufour (and also have an QGIS 191a229 version) on Windows 7. However, when I go through the ...
2
votes
0answers
347 views

WindowsError: [Error 32] The process cannot access the file because it is being used by another process

I am reading images (through Python) and do something. These images are placed in a temporary file, through: tf = tempfile.mkdtemp(filename) I use gdal to read the images (short part of code): ... ...
3
votes
1answer
81 views

I hid the QGIS Menu bar, how can I bring it back? [duplicate]

I was trying to save customization templates in QGIS 2.4 and have managed to hide the MENU bar. Now I cannot access Settings->Customization to switch it on again. I even un-installed and deleted ...
1
vote
1answer
98 views

Create polygons from point dataset, where each polygon contains 3 points from the dataset

I'm using qgis Brighton I have a dataset of 1500 points. I want to create polygons, where each polygon contains n=3 points from the dataset. The aim of this is to have clusters of 3 points, which ...
1
vote
1answer
139 views

How to sum 10 raster bands instead of 9 from code?

I want to sum 10 raster bands but the problem is that the following code will only work for summing 9 bands, which means the output image consists of 9 bands. from qgis.core import * from qgis.gui ...
1
vote
2answers
119 views

The use of QGIS with a Magic Mouse

I have been using QGIS with an Apple Magic Mouse. Despite disabling all the point and click features and gestures in the systems preferences, the maps constantly zoom in and out extremely and ...
2
votes
1answer
116 views

How to re-project shapefile to be compatible with Openlayers satellite imagery

The goal: Visualize a map using google's satellite (and projection) using my collected points. Right now I have a shapefile of my collected points from surveying. I created it by adding my csv file. ...
1
vote
1answer
57 views

How to add neighborhood names from shp to csv data points QGIS

I'd like to add the neighborhoods listed in a shp file to the data points in a csv Link to shp Link to csv Here are the data points overlaid on the shapefile map of the neighborhoods. I'd like ...
0
votes
1answer
83 views

Converting osm_id to OSGB coordinates

I've downloaded from http://extract.bbbike.org/ a map of the waterways and waterbodies within Greater London, Uk. I've loaded the shapefile into QGIS and opened its attribute table. I see that the ...
2
votes
1answer
127 views

SLD based on two attribute values

The map below is produced in ArcGIS software using the multiple attribute visualization tool (a map based on two attributes the color represents different zones based on the zone attribute value and ...
0
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0answers
30 views

Drawing polygon with predetermined area

Is there an option in quantum gis to draw a polygon with the specyfied area and is it possible to display dynamically the area when reshaping the shape of the polygon ?
1
vote
1answer
41 views

QGIS 2.6.1: “no enhancement” option not working on DEMs

When I import DEM raster layers and try to change the contrast to "no enhancement" I get a blank white image in the map window. Changing "black to white" to "white to black", the map remains a blank ...
0
votes
1answer
94 views

How to avoid 'join features by location' for polygon to polygon creating extra areas

I am trying to work out which large polygons contain smaller ones within them in QGIS. I have a set of smaller features already defined (dark green below). However, for those smaller areas which sit ...
3
votes
2answers
599 views

Join table field with shapefile programatically (via PyQgis)?

The following is currently unsuccessful at fulfilling a table field join to a point shapefile in Qgis. All instances of the join object will print the proper values, and no error is flagged when ...
2
votes
1answer
849 views

How to deal with clipper error “cannot compute bounding box of cutline”?

I have merged about 20 OS tiles in to a single raster and I am trying to clip the merged tiles using a single polygon which itself was created from a small number of ward boundaries, merged using the ...
2
votes
2answers
473 views

How to load a data table as a 'vector layer' using PyQGIS?

This might be a simple problem, but how does one load a simple two column CSV with no associated geometric data? I have given a couple go's via QgsVectorlayer[delimited text, spatialite] types - but ...
2
votes
1answer
186 views

Combine Shapefile with address information

I downloaded a UTM32 shapefile (.cpg, .dbf, .prj, .shp, .shx file, where other available georeferences are GK3 and TM32) that shows the exclusive division of Germany in its municipalities. Above, I ...
2
votes
0answers
130 views

How to change the group icon in legend via Python in QGIS 2.6?

How to change the group icon in legend via Python in QGIS 2.6? At version 1.x I did it this way: self.legendTree = self.iface.mainWindow().findChild(QDockWidget,"Legend").findChild(QTreeWidget) ...
1
vote
2answers
189 views

How to make a contour map from a list of points and values? [duplicate]

I need to create a nice map with contours that represent various thematic data on a scale of a country, for instance, average temperatures in Germany. I have a list of coordinates with the values, ...
1
vote
1answer
57 views

QGIS Web Client Raster not visible

I have loaded rasters from PostGIS and Oracle Spatial 11g with below script.Both layers are visible in QGIS Dekstop.My OWS settings are correct but the Oracle raster layers are not visible in ...
0
votes
1answer
154 views

Creating many-to-many table from intersection between two polygon layers in QGIS?

I have created a buffer around several points. I want to intersect this layer with a Census Tract layer. My end goal is to create a table that would list all the census tracts that intersect with the ...
2
votes
1answer
256 views

Keeping symbology style in a polygon shapefile when converting to KML

I have a polygon shape with 23 classes and have created patterned symbology styles which I will like to have retained when I open in Google earth pro. Is there any how I can achieve this in either ...
1
vote
1answer
84 views

How to fill column with several conditions using QGIS field calculator?

I know the synthax in order to fill one field with only one condition (field calculator): case When "attribut" = 'value' then value End But how to do populate automatically one field with ...
1
vote
1answer
36 views

What's the easiest way to generate many attribute-based depictions of the same layer?

I'm trying to show (in QGIS) how the distribution of 7 or 8 different attributes of a given shapefile vary across polygons within the layer. For a given attribute, this is simple (well, the basics ...
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
12 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
226 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 ...
2
votes
2answers
918 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 ...
4
votes
3answers
343 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
94 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
92 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 ...
2
votes
0answers
67 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
141 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 ...
1
vote
2answers
245 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
104 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 ...
2
votes
1answer
69 views

Obtaining block structure from parcel data using QGIS or ArcGIS for Desktop?

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 tool could I use to accomplish ...
1
vote
1answer
89 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 ...
1
vote
1answer
73 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
109 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
247 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
93 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
612 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
247 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
68 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
124 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 ...
2
votes
1answer
183 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
1answer
48 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?