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

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2
votes
1answer
198 views

How can i include program form (created in Designer ) to my QGIS plugin?

How can I include a form created in Designer in my QGIS plugin? And how to get controls values (textbox,label,etc)?
2
votes
1answer
1k views

How can I add button to the QGIS toolbox or create my own toolbox?

I want to create a button and add it to the QGIS toolbox or alternatively create my own toolbox and add the button here. A plugin should be started when the user clicks the button.
1
vote
0answers
1k views

download and installation of sample data [closed]

I have downloaded the sampe dataset under "my documents". When I extract the contents of the zip file, the only folders that are actually installed, are "gml", "gps" and "shapefiles". Thus, ...
0
votes
1answer
1k views

How to install sda4pp plugin with missing repository in QGIS

I see that the repository for the sda4pp plugin went down in 2011. Does anyone know if there is another way to download the plug-in with the repository missing? If this plug-in is no longer ...
2
votes
1answer
200 views

Can't load PYQGIS

I get this error; any comments Couldn't load PyQGIS. Python support will be disabled. Traceback (most recent call last): File "", line 1, in ImportError: ...
4
votes
1answer
157 views

Where are the Spatialite settings stored?

after moving a spatialite-database to another directory, qspatialite says "Can't connect to Database" / Error unable to open database file. Even no project is open or I try to create a new project. In ...
5
votes
5answers
8k views

How to break a single polygon into multiple polys?

I created voronoi polygons after which I dissolved them on the basis of one attribute. Now there are cases where in for one single attribute "abc" I have3 polygons at different places with same object ...
10
votes
5answers
2k views

How to identify duplicate attributes in a field?

I have a point shapefile with thousand of points. It has an ID code field that supposed to be unique. Every now and then the data entry clerk wrongly type the id creating duplicates.Right now I'm ...
1
vote
2answers
584 views

How to fix Error 14 — Unable to open ~/.qgis//qgis.db?

I get this error: Error 14 -- Unable to open ~/.qgis//qgis.db -- QGIS version 1.8.0-Lisboa -- Ubuntu 12.04 It was discovered when I tried to define a custom CRS and save it under: settings/custom CRS ...
9
votes
2answers
287 views

How do you protect your PostGIS credentials when using QGIS 1.7?

I'm fairly certain this should be a community wiki, but I don't know how to make it one. So if an admin sees this please change if appropriate. So.....How do you protect your PostGIS database data ...
3
votes
1answer
502 views

Correct ASTER with SRTM or Topographic Map

I have a problem with my DEM again. I decided to use ASTER GDEM2 (for different reasons). ASTER GDEM2 have its problems, I know, and I dont want to discuss that again. I have to use it, because SRTM ...
6
votes
4answers
1k views

How to sum up pixel values in QGIS?

I need to know the value of the sum of all pixels in a raster. However, in the Statistics section of the Metadata tab in Properties, under Sum of All Cells it always indicates 0.00. I have tried with ...
1
vote
1answer
172 views

Looking for CRS for NAD 83 UTM Zone 30N

I'm curious as to why the UTM zones are incomplete for NAD 83 in QGIS? I have a WGS84 shapefile that I would like to project to NAD83 UTM Zone 30N but can't find it in the QGIS CRS list. I see how ...
3
votes
2answers
1k views

How can I specify the CRS of a raster layer in pyqgis?

I manipulating netcdf raster data from the QGIS python console. The metadata of my netcdf file does not provide the Reference system. However I know it is 'EPSG:4326' I am writing a python script to ...
5
votes
1answer
1k views

How to fill my column with consecutive numbers

I m very new to Qgis, so forgive this simple question. Searching in older topics didn t help either.So: I make a new column in my attribute table and it has a default value(for example 0). I want to ...
1
vote
1answer
1k views

How can I create a custom form to display the attributes of the selected object?

I have already appealed to the selected objects, and found a way how to put them in a MsgBox. But I need to output was in the form
4
votes
2answers
472 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
438 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
203 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
120 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
146 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
176 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
62 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
5k 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
1k 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
854 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
3k 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
262 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 ...
3
votes
1answer
190 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. ...
9
votes
3answers
1k 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 ...
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
665 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
437 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
755 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
300 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
553 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 ...
10
votes
5answers
3k 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
274 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...
7
votes
2answers
1k 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
6k 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
408 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
116 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
407 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
164 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
590 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
492 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
404 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
465 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