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

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0
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1answer
634 views

How to print a WMS map with chosen scale and WMS zoom level?

I am trying to print a WMS map in QGIS. If, while in the print composer, I chose a "25000" scale, the composer chooses a WMS layer that actually shows a 1:50000 map. To get down deep at the 1:25000 ...
3
votes
1answer
1k views

Spatial Join in QGIS 2.2

I am trying to spatially join point layers of some 12,000 women interviewed in Egypt to Egypt's polygon layers (administrative districts boundaries) using QGIS 2.2 and need some advice. I am a QGIS ...
0
votes
1answer
134 views

PyQGIS: How to send signal to call unsetMapTool()

I've created a map tool to add some functionality to adding point features in QGIS 2.0. I'd like to unset this map tool if editing has manually been terminated by user. I've attempted as shown below, ...
0
votes
1answer
119 views

Add attributes to an output shapefile schema (via meta)

I am trying to copy the schema of an existing shapefile and add to it in an output shapefile. Somehow I am not getting anywhere with this...though the docs seem very clear (and the download page : ...
0
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0answers
111 views

How to overlay polygons that are in the same layer

I need to INTERSECT many polygons that are in the same layer. Actually each polygons from my layer represent an area of influence from one specific bird species. Since I used to use ArcMap, I found ...
0
votes
1answer
197 views

QGIS convert polyline to fixed width polygon

I have a shp file of polylines for trails, and I need to convert them all to be polygons that are 8 ft wide (4 ft from the center of each side of the polyline). I tried a following a few other posts ...
6
votes
3answers
429 views

How to get QGIS to play with pandas (Windows)?

has anybody been successful getting pandas to work with QGIS's Python installation, on Windows? I've used the OSGeo4W installer to install QGIS2.2, which comes with Python 2.7 and Numpy 1.5.1. Any ...
2
votes
1answer
423 views

Error: Algorithm not found

I wrote the following code to start using QGIS APIs. in a very short script seen below, the "Error: Algorithm not found" is thrown and "print processing.alglist()" is showing none. Any idea why this ...
3
votes
0answers
110 views

QGIS : launch Atlas composer generation from command line

I am using QGIS 2.2 and have configured a composer with atlas generation. I would like to launch this atlas generation every day. The idea is to write a batch and launch it with a cron. Is it ...
0
votes
1answer
74 views

georeferencing an image from GoogleEarth

What I actually want to do is very simple, however, there seems to be a bug: I have an image from GE which I want to georeference and set as a background layer. I thus set some placemarks on GE, ...
0
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0answers
234 views

PyQgis: How can I preserve order or index when adding features to a Vector Layer from a file?

As I read data from a text file and add points to a QgsVectorLayer (as well as related attributes), each new record gets 'stacked' on top of the previous one in the Attribute Table (and within the ...
0
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0answers
67 views

Slope regions from elevation points using QGIS 2.0

I am using QGIS to create a layer of slope region polygons (e.g. less than 30% slope, 30-50%, more than 50% categories). My data comes from point elevations and I interpolated using SAGA b-spline ...
2
votes
1answer
260 views

Getting length data from GPX files within QGIS

I just got a Garmin etrex and promptly took it for a hike. I can get the path and the trackpoints into QGIS with no issue. However, I cannot figure out how to get the distance between the ...
0
votes
3answers
645 views

Import DEM into PostGIS for QGIS

I'm a complete GIS newbie so sorry if I'm using the wrong terminology in searching for a solution to this... I'm trying to import a DEM into PostGIS and display it in QGIS. The data is from the EU-DEM ...
0
votes
1answer
261 views

DN value from raster to vector tool (QGIS 2.0)

I am using QGIS 2.0 to convert a DEM to vectors, then create polygons of zones of slopes. However, I am unsure of in what units my new "DN" column is. It has lost of precision of z-values from my ...
0
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0answers
275 views

NDVI from QGIS is giving me NaN values

When I use QGIS' "slope based VI calculation" for Landsat 8 IR and Red bands the resulting NDVI and TTVI maps are all NaN values. When I do the NDVI calculation using the raster calculator it looks ...
7
votes
4answers
3k views

Split Lines at Intersection of Other Lines

I have two line layers (roads and contours in this example) and I would like to split the roads layer every time it crosses/intersects a feature on the contour layer. I can't seem to find a tool that ...
0
votes
1answer
80 views

Integrate static database with spatial database

I have some questions about how to integrate static database with spatial databases. problematic: I have several static data bases on different platforms (Oracle, MySQL, SQL Server) I want to turn ...
1
vote
1answer
1k views

Iterating over selected features in QGIS Processing

I used to be able to iterate over selected features using the following script in v2.0. import processing features = processing.getfeatures(layer) for feature in features: #Do whatever you need ...
1
vote
1answer
53 views

Rectangle polygon is displayed as triangle

i am wondering why a rectangle polygon that i have created on an official german surveying website (downloaded as compressed shape in a zip-file) is displayed as a triangle when loaded in qgis. mighty ...
0
votes
1answer
199 views

Blank Shapefile output?

When executing the following command string in the active browser, Qgis projects the triangle polygon and associated attribute table correctly. Upon reopening the shapefile in a new browser, the ...
1
vote
1answer
275 views

OpenLayers Plugin with on-thy-fly-transformation causes wrong coordinates

I am using the OpenLayers Plugin with the maps from Google Satellite. In Qgis I have chosen on-the-fly-transformation into WGS 84. But the WGS 84 coordinates in Qgis are now 0.15 degrees further E ...
0
votes
1answer
213 views

Programmatically set layer properties Python Init function

Is it possible to set the layer properties Python Init function field programmatically? I've been looking through the qgis 2.2 api but can't seem to find anything on it. Hint, suggestions and ...
0
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0answers
80 views

GPS positional, and quality data collection using QGIS

I was wondering if it was possible to record the position along with some of the quality control data in a table when using the GPS information functions to collect some mapping data. I would like to ...
1
vote
1answer
106 views

generate massive shapefiles

I have a shapefile with 1475 records, and I want to generate a shapefile for each record. What can I do to generate them avoiding selecting and exporting each record to do that?
1
vote
1answer
157 views

How to close spaces within a polygon in QGIS 2.2?

I have a shapefile displaying the borders of several city units. One of its polygons, however, had free space consisting of four vertices in it. I created another polygon inside the free space and ...
2
votes
3answers
206 views

Mis-aligned shapefiles in QGIS?

I'm a beginner at QGIS and I'm having trouble aligning my shapefiles. I have two datasets: one originally in WGS84 (lat/long) and another in Corrego Alegre/UTM zone 24S. I need to convert the second ...
6
votes
1answer
3k views

Problems installing QGIS 2.2 on Ubuntu 14.04

After major upgrade to 14.04 I tried to purge and reinstall QGIS. Unfortunately I get and error (full listing below) and cannot finish clean installation. Information in the log points errors to ...
1
vote
0answers
111 views

Highlight paths between two points

I'm new to qgis and very sorry if this is a simple question to ask. IS there a way to highlight the available paths (roads) between two selected points in a road map(in qgis) ? I want to find the ...
0
votes
1answer
246 views

Copy .prj file into QGIS projection folder

I want a custom projection used in ArcGIS be available in QGIS. I have the .prj file copied out of a ArcGIS folder (containing different projections). Now, I want this file to be added into QGIS. Is ...
3
votes
1answer
325 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 ...
0
votes
1answer
122 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
333 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
975 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
112 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
94 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
40 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 ...
5
votes
2answers
3k 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
135 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
223 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
150 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
80 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
135 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
122 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 ...
2
votes
2answers
1k 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
222 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
133 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
69 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
151 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
91 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 ...