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

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2
votes
1answer
216 views

Import error when utilizing QGIS's Python Init function

Based on the answer to Referencing Qt UIs external to plugin with python. I'm trying to utilize the "Layer Properties / Fields / Python Init function" to execute a file (test_file.py) that is located ...
1
vote
0answers
64 views

QGIS API changes from 2.0 to 2.2

I have the same program running on two different machine, one with Qgis 2.0 and the other Qgis 2.2. The machine running 2.2 doesn't seem to render the map canvas. I thought it was how I has creating ...
0
votes
1answer
96 views

How to delete an edge in QGIS

I have used the Lines to polygons tool to turn a city boundary linestring feature into a polygon. However, the tool has connected some nodes more than one time, resulting in multiple edges . I would ...
2
votes
1answer
241 views

How to style the end of a line?

In the picture you can see, the red lines i added manually. These are the ends of the lines. To distinguish that there is the beginning of a new river segment, i would like to have something like ...
7
votes
2answers
747 views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
2
votes
0answers
97 views

QGIS is not working with Postgres Plus Advanced Server

We have a problem to integrate GIS software with our GIS database which is populated on Postgres Plus Advanced Server 9.2 from EnterpriseDB. We are using QGIS to maintain and analyze our GIS ...
0
votes
0answers
73 views

How to provide one label for multiple polygons?

QGIS 2.2 provides a great deal of control through the labeling override expressions, but I don't understand what variables I can use to generate a single label for multiple polygons with the same ...
1
vote
1answer
34 views

Is there a way to use a variable in a rule-based style?

I have several symbol layers: current: "from" <= 1832 AND "to" > 1832 former: "from" <= 1832 AND "to" <= 1832 future: "from" > 1832 What I'd like to do is be able to change 1832 to ...
4
votes
2answers
2k views

Postgis 2.1 error after update

After a usual update progress - "apt-get upgrade" - I can not connect with qGIS to my PostGIS DB anymore. Error in the qGIS logfile: Your database has no working PostGIS support. Erroneous query: ...
0
votes
0answers
111 views

Issues creating slope raster layer from a point layer

I'm trying to create a slope raster layer using QGIS 2.0 on Windows XP. I started with a points layer with the Z elevation attribute. I then used the interpolation plugin to create a DEM. But, ...
0
votes
1answer
137 views

Labels disappear zooming IN in Qgis 2.2 Composer?

I have a simple map with a polygon Layer of 2 Polygons. Labeling is turned on, so is the option of "Show all labels for this layer, even if they collide". In the print composer the labels keep ...
1
vote
1answer
144 views

QGIS Print Composer with ESPG:32615 [closed]

I have imported a PostGIS layer as the only object into my project and set the project and layer CRS to EPSG:32615 (UTM Zone 15N). My layer appears just fine in the work area. When I try to create a ...
0
votes
1answer
63 views

Piechart of a text column from attribute table in qgis

I have this problem: I would like to create a pie chart from a column of a attribute table, and I would like to see this pie chart above the map. The column contains names not numbers (I think fields ...
3
votes
1answer
109 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 ...
0
votes
1answer
107 views

How to georeference a map - which is in projected coordinate system - using geographic lat long? [duplicate]

We have some hard copy maps which were projected in Gauss Kruger coordinate system (in the legend it has been mentioned). But, the coordinates were given in Geographic lat long (Beijing 1954). In ...
1
vote
2answers
634 views

Replacing raster values in one raster with another raster in QGIS … how to?

I have a raster (DEM) and want to replace a few cell's values with the values from another raster in QGIS. I would have done this with the "over" tool in the raster calculator in ArcGIS. Specifics: ...
0
votes
2answers
178 views

Geo- referencing Projected coordinated raster with GCS - ArcGIS

I have raster displaying Lat/ Long grid, but map information shows that, it s been mapped in Gauss Krugger projetion/ Beijing 1954. So, technically we need to geo reference the map in Gauss Krugger/ ...
0
votes
1answer
106 views

QGis and Geomedia via Oracle

When I use both QGis and Geomedia to digitize in the same layer I get some issues in my Oracle table. It looks like Geomedia save my point, lines and polygons as ARRAY, while QGis save it like POINT ...
2
votes
1answer
58 views

Selection of points not showing on top (QGIS 2.2)

is there a way to bring the display of the selected objects on top? I have a large numer of points with a lot of them on top of eachother. When I make a selection through an expression and zoom to the ...
2
votes
0answers
110 views

Where can I find a comprehensive overview of QGIS geoalgorithms?

i am looking for an overview of processing toolbox / qgis geoalgorithms tools unfortunately the link http://www.qgis.org/de/docs/user_manual/processing/toolbox.html seems to be dead. SEXTANTE ... ...
0
votes
1answer
66 views

Errors uploading plugin to QGIS python plugin repository

I'm trying to upload my first plugin to: http://plugins.qgis.org/plugins/add/ I keep getting the following error: There were errors reading plugin package (please check also your plugin's ...
0
votes
0answers
346 views

Split Lines with Points Layer Tool

I asked a question a while ago to figure out how to split a line layer with a points layer using QGIS, but cannot, however, get the accepted answer to work due to limitations of my knowledge and the ...
0
votes
2answers
90 views

Can't get dataProvider object outside of QGIS python Interpreter

Within PyCharm import qgis.core as qgis vector_lyr = qgis.QgsVectorLayer("Point", "distance nodes", "memory") pr = vector_lyr.dataProvider() print pr prints None Within Python Interpreter in QGIS ...
1
vote
2answers
195 views

How to compute percent of a field

I have a layer with a column conaining population values. I want to write an expression to compute in a new field the percentage of population each polygon has in relation to the total population. I ...
0
votes
1answer
226 views

Coordinate grid not showing in Composer

I went through every answer that I found here, but am either missing something in them or the question has not been asked. I have a very simple map consisting of four layers, namely contour lines, ...
4
votes
2answers
239 views

Storing SRID:4326 data as Geometry or Geography?

I used OGR2OGR to import SRID 4326 point data into MSSQL Server. Didn't realize that it defaults to creating a geometry column instead of detecting the data as 4326 and creating a geography column. ...
1
vote
2answers
112 views

How to get a set of all buildings of an OpenStreetMap section in form of single points / Multiple polygons as one point

The objective is to get a set of all buildings of an Open Street Map section in form of single points in a shapfile. I downloaded the section from osm. Imported the section into QGIS (and later ...
1
vote
0answers
105 views

Open PostGIS layer with QGIS 2.2

I just upgraded QGIS from 1.8 to 2.2 and I am getting some troubles to open a PostGIS Layer. The connection with the server works fine, I can see all my tables, select the one I want to open and even ...
1
vote
2answers
293 views

How to align/georeference distorted vector layers in QGIS?

I've got a shapefile which has been digitized from a strongly distorted historical map, and would like to align it as nicely as possible to another precise shapefile layer. The transformation must ...
0
votes
1answer
114 views

How to create a grid after merging shapefiles?

Follow up question to QGIS Model Builder Script - Possible to merge layers in a folder? I think I'm missing something very obvious here but can't seem to find it. After merging shapfiles in a folder, ...
1
vote
1answer
56 views

Why is “Add feature” of the GPS Information tool inactive for some of my PostGIS layers?

Sorry If I rise it again on this forum but I couldn't find any info on limitations/requirements of "GPS Information" tool for QGIS (2.2.0) against data layers. For some layers I'm able to collect ...
0
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0answers
61 views

Is it possible to use custom (non-circle) buffer shapes?

I have a shapefile containing points. I'd like to replace each point by the same shape, centered around the point, like the "Buffer" tool with shapes other than circles. How can I do that?
2
votes
1answer
68 views

Where do I find additional instructions for QGIS print composer?

QGIS Print Composer has numerous complex interacting features. Scale vs paper size vs map extent vs QGIS main window map extent - locked layers - resolution - map rendering level (i.e. the scale used ...
2
votes
1answer
365 views

Can I draw free hand figures in QGIS?

I would like to add free hand drawings to my map. I tried the "Rectangles Ovals Digitizing" plugin but am looking for a free hand (not rectangle or circle) tool. Also is there a plugin similar to the ...
1
vote
0answers
111 views

Merging shapefiles to one, rearrange columns?

I am trying to merge two shapefiles which both contain polygons representing properties in QGIS 2.2. One problem is that the names of some of the columns in the attribute table differ between the two ...
1
vote
0answers
52 views

Running algorithm from Processing takes much much longer time than doing it from Qgis GUI

I have a road layer with 32000 features, and I want to find all the intersections. when I use processing->SAGA -> convert polygon/line vertices to points, it is all done in less than 5 seconds. ...
0
votes
1answer
95 views

Geocode several addresses in QGIS

I am using QGIS and I have an Excel file that has fields with direction and it fails to geocode these addresses. Examples: address apartment township 1 calle 2 avenida ...
2
votes
0answers
362 views

No tables listed in connection to MSSQL 2012 in QGIS

I've (finally) made a connection to my MSSQL 2012 database, but no tables are listed. Here's the tree view of the connection, and the connection properties: Some notes and questions: I've read ...
3
votes
2answers
216 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 ...
2
votes
1answer
290 views

How to get the map canvas CRS in EPSG code?

This is probably a simple request but I cannot find a way around it: how can I read from python the map canvas CRS? I know how to set it up: canvas = self.iface.mapCanvas() ...
0
votes
1answer
56 views

How do add attributes from shapefile to list of lat/long-coordinates using QGIS?

In QGIS I have a csv-file which contains lat/long-coordinates and population data for each coordinate. I also have a shapefile containing certain regional districts, in my case US counties. Now I ...
0
votes
1answer
77 views

Conditional formatting of grid cells based on specifict attribute

I'm using QGIS. I have a 29x30km grid. Every cell of the grid has its ID and every cell of the grid has an attribute "Population" ranged from 0 to 30000. What I would like to do, is to get some kind ...
2
votes
2answers
265 views

Auto fill second column with predefined names depending on first column (QGIS)

I want to create a point layer. In the attribute table I want to have two columns. In the first column I want to type an abbreviation like A. Then I want the second column to be auto filled with ...
1
vote
1answer
106 views

How to open most recent directory using PyQGIS?

For example, when I add a vector layer, next time that I want to add another layer it opens up where I chose my last layer from. How would one implement this in Python and/or PyQgis? I'm writing a ...
0
votes
1answer
160 views

Changing $id in a shapefile in QGIS

I need to change the id (feature.id() in the python API or $id in the field calculator) of for features in shapefile layers in qgis, and I need to do it in Python. Is there a way? I tried something ...
0
votes
1answer
108 views

Georeferencing PNG against Google maps with openlayers plugin

I am trying to georeference blueprints to the footprint of a building. I'm using the Google Satellite image from the plugin to do this. The blueprints are rotated about 30 degrees. When I run the ...
1
vote
2answers
635 views

ToolBar icon images missing

very early build ~ zip file I am getting blank outputs for button images in a custom toolbar. Although the button information populates the dockable toolbar, they lack respective icons [see Fig.1] ...
1
vote
1answer
245 views

QGIS Model Builder Script - Possible to merge layers in a folder?

I would like the user to select a folder via the interface in which all the vector shapefiles inside that folder would be merged. I have been using the Model Builder and looking at example scripts ...
0
votes
1answer
150 views

What is the best way to manage geodata with open source software?

We are a small group of GIS users with different expertises embedded in an administrative infrastructure attempting to switch to a small and low cost open source infrastructure (open source GDI). ...
1
vote
1answer
355 views

QGIS 2.2 Print Composer does not display map with some datasets

I can't seem to get the Print Composer of QGIS 2.2 to work. When I click on "Add new map", the map square is created, but I can't seem to see my data in it, whatever the scale I use or even clicking ...