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

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671 views

QGIS 2.4: plugin changes map tool canvas click behavior from 2.0

I had created a plugin for QGIS 2.0 to add new features more easily. It involves changing extents and updating snapping options along with triggering the default actionAddFeature(). However, I've ...
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1answer
458 views

How to determine bounding box of current qgis 'map canvas extent' from the python console

I've asked a similar question here: How to quickly calculate bounding box coordinates of a selected polygon with qgis ...regarding a quick way to determine the bounding box of a given layer. Is ...
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1answer
181 views

How to automatically fill a lat/long in attribute table

I´m not experienced in using QGis. I need to plot the distribution os a plant species on a map. I have created a shapefile for the species plots (name of file is PLANT). The coordinate system of this ...
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2answers
120 views

How to activate snapping for layer you are drawing polygons in?

I want to draw multiple polygons in a layer that have boundaries without a gap, so I activated snapping for that layer. But it doesn't work. For other layers it works fine.
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2answers
81 views

How to bring all “tourism:attraction” from points table and polygon table together?

Im using OSM data as osm2pgsql-import (from extract.bbbike.org). And I want to draw all attractions ("tourism" = 'attraction'). The most of the attractions I found in the planet_osm_point table. But ...
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1answer
588 views

QGIS contours smoothing and cleaning

Trying to utilize the contour extraction QGIS tool but having trouble creating smoothed contours. The smooth, generalize, and dissolve tools have not worked for me. Also the plugin for contours ...
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3answers
1k views

Calculating slope in percentage

I'm working with qgis, v. 2.0.1. I have several soil types. They are (amongst others) described with slope indications. I already calculated the slope from the dtm in degrees, but as de description of ...
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2answers
218 views

TatukGIS SQLite Spatial vs. Spatialite

I must apologize in advance, I'm just getting into GIS and trying to figure things out. I have an SQLite spatial database that I'm pretty sure was created in TatukGIS. I've tried to open it in QGIS ...
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3answers
69 views

Colorizing raster in QGIS 2.2 without using OSGeo4W command line?

Total beginner in QGIS. Following this guide right now: https://www.e-education.psu.edu/geog585/node/695 At step 4 I created the simple txt file which I now need to use to colorize the raster ...
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2answers
3k views

Drawing tools to add circles, arrows, lines for QGIS?

I'm pretty new in QGIS and i'm searching a drawing tool like it is possible to find in microsoft word or excel. I search something very user friendly (for dummies!) to add circles, arrows, lines... ...
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3answers
342 views

How to add columns with x/y data to Spatialite Layer? [closed]

I´m new here and I am also quite new at working with QGIS. My Spatialite Database looks like this (arch_locations.sqlite) Fields: pkuid short_ID name geometry I´d also like to have two additional ...
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1answer
293 views

How to populate a combobox with layers in TOC?

I am developing a plugin, and I want user to select one of the loaded layers from a combobox. I've already coded this much: self.dlg.show() layerlist = [] self.dlg.ui.layerCombo.clear() # ...
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1answer
453 views

QGIS Map tools and Map canvas--QString errors

I'm trying to learn more about using QGIS Map Canvas widgets and creating custom map tools, so the information from the PyQGIS cookbook is very helpful. After trying to experiment with mywnd.py from ...
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1answer
2k views

How to process MODIS ndvi data using QGIS/GRASS/R?

I have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula (3 tiles), from February of 2000 to August of 2012 (really big data). I want to know how to deal with this kind of files. My ...
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1answer
120 views

How to add pages in print composer

Is it possible to add more than one page to one QGIS print composer Project? For example one sheet for the map and another sheet for the legend ans some other informations. Thanks in advance, Patrick
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2answers
267 views

How can I centralize QGIS connections for multiple QGIS installations

I have multiple computers with QGIS installed on them. I regularly use the same WMS / WFS services. Now I have to connect to these services for each QGIS installation separately. It would be great ...
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3answers
268 views

How do I use SQL in the field calculator to populate a new column?

Courtesy of Geofabrik I have a "places" point shapefile which includes in the attribute table a column named "type". As can be seen in the attached image the column contains fields such as "city", ...
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2answers
877 views

Trying to use a QGIS plugin - getting classFactory error

I've had to create a GIS for the company I work for, choosing QGIS over ArcGIS due to price (company doesn't want to buy another copy of ArcMap). In any case, it's not a HUGE GIS but it would be good ...
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1answer
966 views

Pseudo-Mercator projection with Decimal Degrees?

Hope this isn't a duplicate, did some searching but none seemed quite the same. Projection I want: WGS84/Pseudo-mercator. Selected. Looks Great. Canvas units I want: Decimal Degress. Selected. ...
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1answer
29 views

labeling in qgis 2.0: if one letter in string is “X”

I have a shapefile and I want to label all shapes with a "B" or "A" in its name (string). All others should be ignored. Like: If [field] contains "B" draw label Im using qgis 2.0.
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1answer
483 views

How to remove all selection from all registered layers using QGIS plugin?

I want to remove all selection from registered layer in QGIS using Python. I tried to clear the map canvas using: self.iface.mapCanvas().clear() self.iface.mapCanvas().refresh() but the ...
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2answers
303 views

QGIS export ESRI Shapefile to SpatiaLite format issue

I am trying to export a shapefile of 3221 mixed POLYGON and MULTIPOLYGON geometry elements and every time, I get this same error: Does anyone have any idea what's going on? And no, this is not an ...
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1answer
44 views

Rough edges on tiles in QGIS

I'm loading four .ASC files into QGIS, each containing topographical data about a tile of 10 x 10 km. On the map, this data is displayed as black/white and different shades of gray. My problem is that ...
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2answers
642 views

Alternative repository for QGIS 2.0 plugins

Is there any alternative to the official repository for plugins of Qgis 2.0. I prefer to be a tested and trusted. EDIT: I found a source which refers to OpenGeo Explorer For more info: ...
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1answer
91 views

Problem using pgRouting 2.0

I follow this great post:pgRouting 2.0 for Windows quick guide, and I have loaded the test data from GeoJSON, like this: But I don't know how to load this layer into my database, and my DB manager ...
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1answer
218 views

Join Tables related by a composite primary key in qgis

I have two tables, one has the geometry and other has attributes. The table with geometry has unique number primary key, and 4 columns admin1,admin2,admin3,featureid. Table two is a csv file has the ...
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3answers
435 views

How to access user credentials in database connection?

I am trying to automate a couple of things when a QGIS plugin is activated: If Layer A is not in the TOC, add it. This requests username and password to access a PostGIS table using the inbuilt ...
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1answer
326 views

How to automate creation of PNG maps using Python?

I have a project with 50 vector layers and I have done custom styling for them. Now I want to make around 30 png files with different xmin, ymin, xmax, ymax. The output size (png) should be width ...
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2answers
154 views

How do I Fix Projection Issues in QGIS

I have some exiting shape files that supposedly have a CRS of OSGEO:41001. If I import new data, and set the CRS to OSGEO:41001 they do not align. If I change the CRS of the new layers to ...
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1answer
92 views

What is the use of Automatic overview support in Qgis 2.0?

Automatic overview support in map frame is one one of the new feature added in QGIS 2.0. In QGIS 2.0 Documentation explanation about this is given as Automatic overview support in map frame: "Need ...
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1answer
2k views

Convert String to Integer in QGIS tables

I want it to know how to convert string field values to integer values in QGis Dufour... there are numbers and strings in the same field, when I use toreal(string) it stops and it won´t create the ...
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1answer
388 views

Is there a way to download more than 13MB of OSM data to QGIS?

I'm using QGIS to make maps with OSM streetmaps data. Problem is that with QGIS -> Vector -> OSM -> download data, after about 13MB I get "Download error Operation cancelled". Sometimes I get ...
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2answers
2k views

Calculating many shortest paths with pgRouting

I 145013 Danish addresses, and 10 big cities in Denmark as points in QGIS. Furthermore, I have four vector layers that connect all the points. They are small roads, main roads, freeways and ferry ...
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2answers
2k views

Convert .asc format into shapefile

I've got some data from "http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp" and it is in *.asc form. To process them I need to convert them to shapefile (need to merge them all into one shapefile and ...
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1answer
620 views

How to sum up multiple columns values into one single column

I have one table containing many columns. Using field calculator, I want to create a new column containing (for each line) the sum of all columns values. Pretty dumb, but just cannot find the correct ...
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1answer
47 views

Is it possible to extract many municipalities out of a state map at once?

Is it possible to extract many municipalities out of a state map at once? I mean not to have to do the QUERY for each and one of them? Thanks in advance.
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3answers
912 views

How to select features of visible layers in QGIS

In QGIS 1.8 I used plugin "Select features of visible layers by rectangle" to know the layer that owns a visible feature. In QGIS 2.0.1 this plugin is no more available. I wonder if it is possible to ...
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1answer
159 views

Is it possible to use AcuGIS with QGIS?

Has anyone use AcuGIS, a web hosting service for PostGIS and GeoServe? I am curious to see how it works with QGIS. I am looking at some cloud hosting services for PostGIS and I would like to be able ...
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3answers
1k views

Why do area calculations return negative values?

I have created a shapefile with some polygons and am now trying to calculate the area of these polygons. The original CRS was WGS84, I have reprojected it to WGS 84 / World Mercator so unit is metres. ...
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4answers
194 views

What units are my coordinates in?

I opened a georeferenced NAIP photo to a new project in QGIS. The coordinates were expressed as: 2199240.6, 616858.7. The same point in Google Earth was expressed in degrees, minutes, seconds, as ...
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1answer
48 views

Why are color settings not saved when exporting to a new file?

I extracted with QGIS a municipality from a state map, then divided it with a grid. I don't want the borders of the grid features to be seen so I changed the color of the map and the color of the ...
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1answer
267 views

How to create “two-dimensional” color ramps in QGIS?

Is there a way in QGIS to create a "two-dimensional" color ramp for the graduated symbology; i.e. a color ramp that determines a color based on two different attributes? My situation is that I want to ...
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1answer
407 views

Pie-Chart Coordinates in QGIS

I have a map of a region and I am plotting pie-charts (as diagrams) over every country in that region in QGIS (1.9.0). I also need to connect those pie-charts with lines (which I am creating in the ...
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2answers
501 views

How to search and move to feature in QGIS?

After solving how to search text string I need to move to the selected feature. Is it possible to do that?
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2answers
656 views

Qgis - need to draw exact lines (mtrs) with fixed angle

I use GIS 1.8. I have the need to be able to draw exact lines and shapes on a bing map. (This is to project a yet to be build greenhous project on a map to show what i would look like). I have ...
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1answer
2k views

How to search text string and select item in QGIS?

I have a table attribute with complete roads name. I have to search items by digiting a part of the road name and I need to colour all the items selected. eg: ROAD NAME: / road 01 / road 02 / road 11 ...
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1answer
129 views

How to write a expression in field calculator for finding $X and $Y?

I'm trying to calculate the lat/long of points using the Q GIS field calculator.Nathan W suggested to First, save the layer as WGS84 and import it again. Then in the field calculator you can use $x or ...
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2answers
1k views

How to fix OpenLayers plugin for QGIS Master?

I can't get the OpenLayers plugin to work in QGIS Master (1.9), I loaded the repository successfully, but the plugin doesn't come up as an option anywhere. I'm new to this, but have tried to make ...
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3answers
460 views

How to calculate line centroids for 460,000 features?

I have a large shapefile of lines, and want to run a mmqgis function (Plugins --> mmqgis --> Modify --> Convert Geometry Type.) The problem is the file is very large and crashes the program. What ...
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2answers
143 views

How to clear attribute columns from a Shapefile?

I want to clear all columns from a SHP. Only need geometry of features. I use QGIS and Sextante with grass and saga. Is there any tool for this job...