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

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4
votes
2answers
706 views

How to represent an imaginary flat world in QGIS without using a round-world CRS

Like one or two other users, I'm interested in using QGIS to map an imaginary flat world. A previous answer suggested simply refraining from defining a CRS for such a world, but I cannot seem to make ...
1
vote
2answers
519 views

How to batch process (100s) of interpolations in QGIS or other open source software programs?

Is there an efficient way to run 100s of interpolations in QGIS or other open source software programs? I have groundwater contamination data collected from monitoring wells at about 800 different ...
3
votes
1answer
247 views

How to calculate maximum distance to an interpolated value along a contour in QGIS?

I'm planning to enter concentrations of groundwater contaminants collected from well locations into QGIS and then use interpolation functions to create contours of the groundwater plume. Can QGIS ...
6
votes
1answer
136 views

Finding Ring Smaller than a certain tolerance

In Simplifying a shapefile for world timezones http://efele.net/maps/tz/world/ all generalize/simplify algorithms fail on 5 countries/states, shown in this shape file ...
3
votes
1answer
155 views

How to display a particular area?

Hy, I'm developing a plugin in python for Qgis. I would like the user to select a particular area in a list (let say a country list) and zoom in the map on the corresponding area. Actually I'm ...
0
votes
1answer
250 views

Qgis : QGraphicsTextItem's position not updated?

I'm using QgisInterface->mapCanvas()->scene()->addItem(QGraphicsTextItem) to add a QGraphicsTextItem to the map canvas. The problem is that when I use the pan tool to move the display the added ...
0
votes
0answers
63 views

How can I create form with controls using QGIS(python)? [duplicate]

Possible Duplicate: How do I build a custom form for entering attributes in QGIS Help me, please create a form with controls using QGIS plugin. Thanks!
5
votes
2answers
6k views

snapping polygons and lines

I recently downloaded QGIS on a Mac OSX 10.7.4 (lion) and purchased a master map shape file, of a particular area. I am trying to divide it into polygons following features on the master map vector ...
6
votes
1answer
2k views

Why does QGIS Simplify Geometries delete entire polygons?

I am reducing the size of a world timezone shapefile, http://efele.net/maps/tz/world/tz_world_mp.zip But at a 0.01 tolerance, entire countries disappear Anybody know a way round this? QGIS shows ...
5
votes
1answer
1k views

Auto node drawing tool in QGIS

I'm new to QGIS and am more familiar with MapInfo. I've been playing around with QGIS to do some habitat mapping based on aerial photography and was wondering if there is a feature in QGIS which ...
4
votes
2answers
5k views

How can I extract data from OSM which includes the street names?

I am exporting OSM data (in .osm) files to use in qGIS. I am interested in having the street names displayed. I know they are in the OSM data set because they are displayed when I browse the data ...
3
votes
3answers
312 views

How to visualize the vertices of a graph in QGIS?

I tried to visualize the graph generated by osm2po and rendered that graph in qgis. Now what I am trying to do is plot the vertices in the graph. So that I can visually see where the nodes/vertices ...
4
votes
1answer
209 views

Can Openlayers plugin be faster?

Can the Openlayer QGIS plugin be modified to have better map loading performance? I use only google satellite/maps. Thanks.
2
votes
1answer
1k views

Problems with Google layers plugins

I currently use Quantum GIS 1.7.4 at work and I have trouble to open Google layers extension. In fact, when I start QGIS 1.7.4 the following message appears and I cannot use Google layers extension. ...
10
votes
3answers
2k views

How to prevent text labels from overlapping other markers?

Is their a way within QGIS to prevent text labels from overlapping icons used to label a point layer? In the example map shown below, there are two layers: Roads layer which is labeled using the ...
4
votes
1answer
448 views

Sub-dividing a polygon into smaller polygons

In OpenStreetMap data, some large areas are tagged with a residential=yes tag. Actually within this large polygon there are multiple smaller (rectangular) houses (which are actually not drawn as yet). ...
2
votes
2answers
2k views

How to access attribute data type in QGIS?

I've been developing a plugin on QGIS platform using PyQGIS. So far plugin does the following: You can select any feature of the already loaded vector layer in QGIS. After selection, plugin displays ...
2
votes
1answer
996 views

Filtering a raster by pixel value ? (Qgis)

I have downloaded Globcover data in GeoTIFF format. I want to create a new grid which only has values where the Globcover data (the only band in the TIF file) has one certain value (==190). Can I do ...
5
votes
1answer
558 views

How to handle spatial join 10 chars field name limit?

When I try to perform a spatial join between a point and polygon file, I get a notice saying spatial join will not be performed because following field names exceed 10 Characters. Kindly help to ...
2
votes
1answer
958 views

How to draw lines, dashed lines, routes and add images to the QGIS mapcanvas?

I need to draw a rectangle in a map canvas and inside it draw routed dashed lines and add small images to it. These actions are to be performed using the QGIS API. Is there any place with examples ...
1
vote
1answer
398 views

Adding table from Postgis

While trying to import a table containing raster data in QGIS , Raster column is not being imported ... I am getting following messages: Database connection was successful , but the accessible ...
1
vote
1answer
737 views

QGIS WMS ver 1.3.0 Exception with GeoServer

I'm trying to load WMS layers from a local GeoServer into QGIS so that I can edit them. I can access and edit the same layers if I access them directly from a PostGIS database. However, trying to load ...
11
votes
5answers
5k views

How can I map a matrix of origins and destinations in QGIS?

I have a central point on a map, and I have other points in a separate layer (the location of a venue, and the origin cities of the venue visitors). Is there a plugin which would generate output ...
2
votes
1answer
341 views

How to connect QGIS to a WMS-C with python?

I would like to connect my QGis to a WMS-C server when my python plugin load. How can I do that ? BTW, the method: addRasterLayer do not seams to handle WMS-C layer...
9
votes
2answers
2k views

Trouble with graduated symbols after joining shapefile with csv file

I have successfully joined data from a csv file to a shapefile in QGIS but for some reason I am having trouble symbolizing my data. I want to use a graduated symbology however this option is not ...
7
votes
2answers
8k views

ECW for QGIS 1.8 in Ubuntu 12.04

I have followed various online help guides on how to make ecw for QGIS 1.8 work in Ubuntu 12.04. I had it all working in Ubuntu 10.04 but since migration to 12.04 no such luck. Is there a guide that ...
3
votes
1answer
459 views

Use QGIS to visualize OpenStreetMap data

I have a osm map for a certain region. Also using osm2po I extracted the graph which includes edges and nodes into the database. Now I want to visualize the map and then visualize the shortest path. ...
2
votes
1answer
131 views

Reproject an aerial layer in QGIS and then open with ArcEngine?

I have an Aerial layer (.SID file) which I would like to re-project in QGIS, then I would like to open it in ArcEngine. I've figured out how to do this with vector layers in GGIS, its just a right ...
2
votes
1answer
533 views

How Can I get the Open Modeller plug-in for Quantum GIS 1.7.4?

I would appreciate if you can tell me to install the plug-in of Open Modeller in Quantum GIS 1.7.4. It is not in the list of plug-in in the spanish version of the QGIS. Thank you,
2
votes
1answer
3k views

How to find polygons centroids? [duplicate]

Possible Duplicate: Get list of coordinates for points in a layer? Sorry for another basic question - my map is almost done but now my boss wants me to enter new outbreaks (that we don't ...
2
votes
1answer
205 views

After re-open of old project file, several layer selections no longer available

I'm new to QGIS. I created a QGIS project, loaded 1 to 3 shapefiles via Add Vector Layer (from 2008 TIGER/Line Shapefiles http://www2.census.gov/cgi-bin/shapefiles/state-files). The maps look fine ...
4
votes
0answers
754 views

Does QGIS have these CAD editing functions? [closed]

I tried QGIS for the fist time today and it seems quite capable for the task that I have in mind. However, I really miss some basic editing functionality from another GIS software that I have to use ...
11
votes
1answer
594 views

QGis raster terrain analysis - The curvature filter puzzles me

I am a french Master student at university Grenoble INP, and during my master project I have worked on DEM (raster) terrain analysis. Thus, I have read the source code of several QGis-1.7.4 raster ...
4
votes
1answer
515 views

How to add attribute data up?

Sorry if this question is too simple/easy for you guys, but I'm still learning QGIS and pretty much teaching myself where I can. Is there a way to add data from 2 columns into one new column inside ...
1
vote
0answers
690 views

Symbol rotation by using rotation-field [closed]

I want to rotate my symbols using the rotation-field in my atribute-table. After choosing the rotationfield, my symbols become invisible (the text is still there). What happend? Thank you! Martin
2
votes
1answer
6k views

Convert a Tif raster file to vector shp file in QGIS

So I've been trying to convert a georeferenced Tif raster file into a vector shp file using QGIS. It's seems to complete this but it ends up giving me a feature class that has over 500,000 features, ...
2
votes
0answers
142 views

Does QGIS preserve Feature Class Relationships (1to1 or 1to many or Many to many relationships)?

Does QGIS preserve Feature Class Relationships (1to1 or 1to many or Many to many relationships) and can the related attributes be clicked and viewed through the identify feature tool?
11
votes
4answers
5k views

How to create equidistant points in QGIS?

I am trying to create points (new layer) at specific distance along the road (existing layer) in QGIS. This gives solution for ArcGIS. How to achieve this in QGIS? This one explains how to create ...
1
vote
1answer
2k views

Projection in QGIS - Scale bar and measurement

When I load a *.csv file (delimited text) as a layer in QGIS, the scale bar shows degrees (for example 0 to 10 degrees). When I uncheck On the fly projection and change the units for feet or meters, ...
6
votes
1answer
476 views

How to find the shortest path within a polygon? [closed]

I am trying to find a way to calculate the shortest path from one point to another without crossing the boundaries of a polygon. I would like to do it with QGIS as I do not have access to ArcGis. It ...
4
votes
2answers
827 views

How can I add OpenLayers layer from the python console?

I am new to the python console. How can I add a layer from the OpenLayers plugin from the python console? Thank you
2
votes
2answers
616 views

How to recreate Mapinfo labels in QGIS?

I try to convert a mapinfo tab-file containing textobjects wich are positioned and rotated in mapinfo into a shapefile or something similar without loosing all information. All information is located ...
5
votes
1answer
5k views

Trouble exporting from QGIS to Illustrator

I am having trouble getting my files to transfer or export to a vector file. When I open the file in Adobe illustrator there is a lot of information missing. I have tried to "save selection as a ...
2
votes
1answer
204 views

Qgis C++ plugin translation

I'm having issues with the translation of my Qgis plugin. static const QString sName = QObject::tr( "Editeur Monoscopique 3D" ); MyClass::MyClass( QgisInterface * theQgisInterface ): ...
2
votes
1answer
672 views

How to display local file's geometries as rubber bands in QGIS

I'd like to get geometries from a local file (e.g. GML) displayed as rubber bands (QgsRubberBands) in QGIS. However, I wouldn't like to load the layer into the map because in the real scenario there ...
23
votes
1answer
18k views

How to install a QGIS plugin when offline?

Due to various IT policies at my workplace, QGIS is installed on a machine that is not connected to the internet. I wish to install a couple of QGIS plugins on this system. I have downloaded the ...
2
votes
3answers
638 views

vector tool missing when install QGIS 1.7.4 on new computer

I installed QGIS version 1.7.4 a few months ago. Under the menu Vector > Data Management Tools I have two options to make a join: 'Join Attributes' and 'Join attributes by location' (see screenshot). ...
3
votes
1answer
1k views

How can I add a grid (from projection MTM8) on my layers

I need to add a grid on a map I created with my own layers and GPS data. How can i do this? I know how to do it in Arcgis, but not in QGIS.
2
votes
1answer
382 views

How do you calculate positional accuracy in qgis?

How to you compare two layers in QGIS to get the positional accuracy?
1
vote
0answers
151 views

How to call a PNG file with MapServer and a Google base layer? [closed]

How can I call a png file from map path including a Google map as base layer? I'm working with MapServer and I have some shapes made with Quantum GIS and ArcView. I can call those shapes in a url and ...