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

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2
votes
1answer
468 views

How to manage null values in QGIS

I made a merge of several AsterGdem blocks near Egypt and Israel. I have portions of the Dead and Mediterranean Seas. Since near Galilea elevations are below sea level this makes the following problem ...
10
votes
1answer
1k views

Is it possible to take automatically a “screenshot” of my selected feature in QGIS using Python?

I am implementing a tool which allows the user to create a profile of a feature (in my case urban parcels). Is it possible to automatically take a screenshot of this feature (displayed in a QGIS ...
2
votes
3answers
2k views

Convert coordinates to geometry (polygon) using QGIS

I have an Excel sheet with grid data including geographical coordinates. I know that the coordinates represent areas, i.e., a multi(polygon). However, the data lacks geometry information. I'm looking ...
1
vote
1answer
355 views

python qgis.core import error caused by spatialite libraries

I have an error when trying to import qgis.core to python: >>> import qgis.core Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: ...
4
votes
4answers
479 views

Why does the layer list context menu not open anymore?

I cannot access layers properties (i.e. change color, filter by query, anything). The mouse right click doesn't do anything. Is there a way restoring qgis to default? Ubuntu 12.04, QGIS 1.8
1
vote
1answer
521 views

Is it possible to convert a Geoserver SLD to Quantum QML format?

I have a web application which runs on Geoserver. I am migrating my application to desktop and am struck at applying the same color schemes and symbology. I am not able to find a way to convert SLDs ...
5
votes
2answers
2k views

Does OSGeo4W install a 32 bit or 64 bit version of QGIS?

I just want to know if you are installing Qgis via OSGeo installer on a windows 64 bits OS (XP, vista or 7) Does it install a 32 bits or 64 bits version of QGIS? Usually the stand alone installer ...
2
votes
4answers
2k views

Qgis: How to display special characters German “ÄÜÖß” in a Map?

I have a shape file with names for Regions. These don't seem to contain special characters but ugly hyroglyphes. What can I do do display them correctly. If I import the shape as UTF-8 it doesn't ...
0
votes
2answers
268 views

Why doesn't QGIS accept my manually altered geospatial column?

I have a table with a geospatial column with srid 28992 but noticed that if i try to show it in QGIS (v1.9) on any openlayer map (through the OpenLayers plugin) it is off by a few hundred meters. ...
0
votes
1answer
170 views

QGis : superimpose 2 rasters georeferenced (adjustment)

I am pretty new in QGis and I encounter the following problem. I have 2 rasters, let's say, "cadaster" and "tranchot". The raster "tranchot" was georeferenced from the raster "cadaster" with QGis. ...
6
votes
1answer
402 views

How to generate non-merging buffers in QGIS?

I'm using QGIS to construct some fixed width buffers from a coastline shapefile. Is there a way to easily handle overlaps/ median lines? (I'm not sure if there's a particular term or phrase I should ...
1
vote
1answer
5k views

Opening TIFF DEMs in QGIS

I have files, in Tiff format, downloaded from ASTER-GDEM. Can I open this file with QGIS? If yes, how? Thanks in advance
3
votes
1answer
2k views

pyqgis: How to get features of selected geometries

I wonder if anybody could provide an example how to get the attributes of selected Features? I tried the folowing Code in the python Console - but I'm stuck at the point where I'd like to get the ...
2
votes
2answers
178 views

How to set the color of a feature depending on attributes with PyQGIS?

I'm trying to set the color of a vectorlayer feature depending on the feature attributes with PyQGIS. How do you acces the attributes of a vectorlayer feature?
0
votes
1answer
263 views

Edit multiple tables with the same structure at the same time?

does anyone know how to edit multiple tables at the same time? I have multiple .tab files and I want to change the order of the fields. Is there any way to do this for all of them at once. They all ...
3
votes
3answers
1k views

How to digitize polygons from georeferenced raster file

I used QGIS to georeference a raster file of a custom US map. The map has features which are not strictly defined by state borders. I would like to digitize the map by creating contiguous borders for ...
1
vote
1answer
3k views

Exporting Symbology from ArcGIS for Desktop to Microstation or QGIS?

I am using ArcGIS 10.1 for Desktop and trying to figure out how to export my symbols of elements in ArcGIS to CAD or QGIS readable format. The problem is, that I can export symbology to a Style, or ...
1
vote
2answers
2k views

Clean way to install gdaltools plugin for QGIS on OSX

I have qgis 1.8.0 on osx mountain lion and am installing the gdaltools 1.2.29. I have run into a problem that a number of people are seeing. The plugin cannot find my gdal python (see below). ...
1
vote
1answer
195 views

what raster format for r.los in qgis

What raster format should I use to create viewsheds in QGIS using the grass r.los plugin? I am using the Ordnance Survey Opendata DTM (tried both ascii and shapefile formats) and srtm geotiffs but ...
0
votes
1answer
348 views

How to save bookmarks with names?

When I create a bookmark the name and project that I enter are not saved when I click Close. The manual says there should be an OK button but there isn't. Using QGIS 1.8 thanks!
1
vote
2answers
707 views

Primary key field hidden on attribute table added to QGIS

I'm having the following issue with QGIS. Adding a sqlite text table (Layer > Add Vector Table) QGIS hides the primary key field (having name id). I understand also QGIS uses this field as unique id, ...
0
votes
1answer
648 views

How to insert images in print composer?

I do not seem to be able to paste an image from mac i photo to QGIS print composer. When i click on add image I get a blank box with no photo. Also when I click to add a label I do not seem to be ...
1
vote
1answer
128 views

QGIS systematically guesses wrong CRS

QGIS (1.7) systematically applies the wrong CRS when adding layers (or shapefiles from a given lot). They should be NAD83__MTM9 (EPSG:32189), as can be inferred from the prj-file, but the ...
1
vote
0answers
462 views

Does QGIS read NAS data?

I wonder if it is possible to load German NAS-Data into QGis or to convert them to Shapefiles. I'm using QGIS 1.8 on Ubuntu 12.04. Thanks I'm sorry, I thought I did - NAS is the new ...
4
votes
2answers
314 views

Is there a Legend Limiter in QGIS?

Is there in QGIS a function or a plugin that works similar to Legend Limiter in ArcGIS? The attribute I want to show in my legend has many possible values, I want my legend to only show those values ...
0
votes
0answers
171 views

QGIS 1.8 problem with rendering polygons in WGS84 on Ubuntu 12.04

I'm using QGIS 1.8 on Ubuntu 12.04. If I add a polygon layer in SHP format and WGS84 projection and start to zoom in, from a scale of 1:200.000 aprox. polygons on the edges are not drawn anymore and ...
2
votes
1answer
307 views

Is there an itemSelectionChanged Signal in Attribute Table?

The QgsVectorLayer class emits a selectionChanged() signal . If a QGIS user for example selects a record in the Attribute Table of a Vector Layer - a selectionChanged() signal is emitted an can be ...
5
votes
5answers
1k views

How to generalize and vectorize a LandUseClassification raster file?

I want to vectorize that rasterfile with its 6 landuse classes. The classification is very noisy and have to be generalized before. The result should be a polygone vector file. I use SAGA, (GRASS) ...
14
votes
5answers
2k views

Find pseudo nodes in free GIS software

Software gvSIG OA Digital Edition 2010 have tools topology for finding pseudo nodes in linear geometry. I set cluster tolerance 0.00002 and maximum number of errors -10000 for 20000 link count linear ...
2
votes
0answers
348 views

Setup of development environment of QGIS on windows with qt creator

Can anyone help me in setting up environment for working on QGIS on windows using qt-creator? I am using qt creator version 1.3.1,qt version 4.6 and QGIS version 1.8. Thanks.
4
votes
3answers
4k views

How to convert the file with projections in meters to Lat-Long in QGIS ar Erdas Imagine?

I have file in Lambert Conformal conic format for the data of Australia, Its coordinates are in meters. I want to convert it to Latitude-Longitude format. Which Projection, Spheroid and Datum I should ...
1
vote
2answers
1k views

shape file coordinate system

I added a shape file of Iran to Qgis. 'Tehran' has 35.6833° N, 51.4167° E coordiantes, however Qgis shows Tehran with 4772860,31296767. How i can view coordinates of a city or location in latitude ...
5
votes
2answers
3k views

How to change position of columns in attribute table?

If I have an attribute table with columns A B C D, is it possible to move the columns to different positions, say, B C A D? When making a new column with the field calculator it would be useful to put ...
2
votes
1answer
482 views

Could not commit changes to layer X

I am editing a layer's (Z) attribute table. I made some columns, used the field calculator to fill them up, made some more, went back and deleted some and then tried to save the edits and got the ...
4
votes
8answers
4k views

How to get OS Mastermap data into QGIS?

I have been tasked with getting OS Mastermap topography data into QGIS system to compliment our other map layers. The data comes in .gz format. Which I am told needs to be decompressed before I can do ...
1
vote
1answer
618 views

Openlayers Overview and OpenLayers versions

I have installed OpenLayers and the Openlayers Overview plug-ins but I am not sure if they are working. I can create new 'open' layers from the Openlayers plug-in drop down, but when I try to add a ...
2
votes
1answer
297 views

Vectors created in OTB Monteverdi are displaced

I'm using the Orfeo Toolbox Monteverdi in combination with QGIS in order to produce classified vectors of vegetation cover which I then use in maps in QGIS. (I can't use the QGIS OTB plugin because as ...
2
votes
2answers
994 views

FIeld calculator gives integer not a real as requested

Two fields "population" and "F06_popula" (both integers) were used in calculating a new field pct-diff. I asked that the new field be a decimal with a width of 10 and precision of 3. The result has ...
5
votes
3answers
2k views

Add 3rd party repositories button not in version 1.8.0 Lisboa

The available manuals and other help sources all refer to the 'Add 3rd Party Repositories button' in Plugins>Fetch Python Plugins and then the Repositories Tab. My problem is that the installation of ...
11
votes
1answer
3k views

How to add labels outside of features?

I'm trying to achieve this kind of labeling using QGIS. Apparently, it doesn't seem to be easily supported. Would you have an idea for a workaround ? I managed to have circled text using ...
6
votes
2answers
2k views

What are valid values for “data defined” labeling settings?

I'm using QGIS 1.8. I'd like to customize label features on an existing shapefile using the new label engine and it's "data defined settings" option. I'd like to know what the attribute table field ...
1
vote
0answers
139 views

Is there an equivalent of arcgis' eliminate feature for QGIS?

I already know of grass' v.clean, but I'm looking for something that doesn't involve third party software. Python scripts or addons are good candidates. What is arcgis eliminate : ...
2
votes
0answers
334 views

How to create polygon “stamps” and extend lines by fixed distance? in QGIS

This is related to Does QGIS have these CAD editing functions? Cadtools have solved a lot of the issues I had but I need the ability to see how long a line is while I am drawing an orthoganal ...
6
votes
1answer
537 views

How to offset points along a line in QGIS?

I used the "Profile from Line" plugin to create evenly spaced points along a line in QGIS, but I'd like to offset them to either side of the line. I suppose I could draw two lines parallel to the ...
4
votes
1answer
1k views

How to find all intersections and count lines arriving at each intersection?

I'm having a hard time getting off the ground with this, and am trying to move away from ArcGIS / arcpy. I have a shapefile with a network of polylines. I want to find/count all 2-way intersections, ...
3
votes
1answer
827 views

How to implement signals on add or modify feature?

I've created a test plug-in in QGIS successfully, but have had a hard time implementing a signal on a vector layer event (add or modify feature). I've add this to my initGUI method: ...
6
votes
1answer
361 views

Simulate (Mock) GPS Tracks

I have the following scenario: 1) I need to create GPX files for use in testing of a mobile device. 2) The tracks to be described within will span large distances over long time periods (i.e. it's ...
0
votes
0answers
25 views

add 3rd party repositories [duplicate]

Possible Duplicate: How to install OpenLayers plugin in QGIS1.8 "add 3rd party repositories" is missing from v 1.8 QGIS plugin installer. I would like to access the Openlayers plugin which ...
1
vote
2answers
398 views

QGIS GPS position after entering attributes

I would like to be able to fill a form and, before, during or after, be able to cath a GPS point. I already know the GPS extension but I have to catch the point and enter attributes after... Idea how ...
2
votes
2answers
1k views

How do I use ranges for raster colour map in QGIS

I have a raster layer in GeoTIFF format, with continuous data values between -1 and +1. For the colour map, I would like... >0 to be green = 0 to be grey <0 to -0.25 to be pink <-0.25 to ...