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

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187 views

Spatial analysis using QGIS or ArcGIS for Desktop?

I am working on the spatial distribution of commercial parking public spaces. I made a database (NUMBER PARKING PLACES, NUMBER OF PARKING MONTHLY), business subjects with adresses with activity. I did ...
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1answer
183 views

G_realloc: unable to allocate 46320000 bytes of memory while managing large .xyz through v.in.ascii

I tried to convert large (~180MB) .xyz file into vector through v.in.ascii in QGIS Brighton (2.6.0) Grass plugin (it should be Grass version 6.4.3). The "primitive registration" stage lasted very long ...
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2answers
132 views

How can I generate batch of coordinates from linestring to simulate driving on map?

I have a openlayers map and I want to simulate driving a route on it. I would like to draw a line (using GPX tool) and create gps coordinates (preferred with advancing time stamp) so I can query them ...
2
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2answers
218 views

How calculate pixel by pixel the mode (statistic) of multiple rasters (geotiff)?

I have 12 land cover maps, and I would like to calculate the mode to each pixel of the 12 maps (they have the same resolution and dimension). I mean, the final map would be the mode for each pixel of ...
3
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1answer
151 views

How to order points along a line?

I have a bus line with bus stops along the route. The sample data looks like this: LINESTRING (-70.57243474999999933 -33.37452829000000065, -70.57308152999999606 -33.37470645999999874, ...
2
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1answer
108 views

How to access a specific feature?

Is it possible to go to a specified row number (or perhaps the next/previous) row using PyQGIS? This code gets the value of the first attribute in the first row of the table features = ...
2
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1answer
42 views

How do I count the number of cells which can see each cell in QGIS

For each cell in a DEM I'd like to count the number of cells which can see it (i.e. direct line of sight) - Can anyone explain how to do this in QGIS? Thanks,
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36 views

Change programmatically to RuleBasedRenderer

After loading a shape as layer in qgis i want to use a rulebased renderer instead of the categorized one. i've tried this code: QgsVectorLayer* ...
2
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2answers
276 views

Add a serial id column inside a view

Is it possible to create a new id serial column inside a view? I need it to be able to add my view in postgis I have made a full outer join on two tables I need a unique PK to load the view in ...
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1answer
66 views

Initalize plugin with current working directory?

Upon starting Qgis, a (currently under construction) plugin needs a means of checking the current project/legend/registry. This checksum would ideally occur upon startup automatically. As the plugin ...
2
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1answer
128 views

Error with adding map layer to QGIS?

I am working on a project on QGIS were a i have 50 geographical point i would like to put in map. The reference system is the UTM Zone 36S. I have successfully imported the coordinates but after i ...
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0answers
90 views

How to query a WMTS layer with a point layer in QGIS?

With the "identify" tool it is possible to query WMTS layers. Then, you can copy the acquired attributes and afterwards the clicked coordinates, then create a CSV file with attributes/coordinates. Is ...
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2answers
288 views

Batch add column to layers and add layer prefix in PyQGIS

I have a number of layers each with a prefix like A_ B_ and so forth. I'd like to: Add a column (text) called DENSITY to each shp Add the prefix letter from the layer name to each row in the ...
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0answers
48 views

Can I use custom icon in QGIS?

Some custom icons created in AutoCAD maps turns into dots on QGIS. Can I use a custom icon On the QGIS or a custom icon in AutoCAD can be displayed correctly on QGIS?
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0answers
48 views

Systematic inaccuracy in QGIS shape area

I’m trying to find out why I get different area figure in QGIS than in AutoCAD when I’m using the same shape file? What I did is I drew a shape in AutoCAD, imported it in QGIS and used the field ...
4
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1answer
537 views

Unsupervised classification in QGIS

I was trying to learn unsupervised classification in QGIS 2.6 following the tutorial video: https://www.youtube.com/watch?v=mI80eENtWSE When trying myself, clicked Run during the process it shows the ...
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0answers
206 views

Add vector tile sources to QGIS

Is it possible to add vector tile sources (using MapBox's protocol buffers format, or GeoJSON, or otherwise) to QGIS? If so, how? (My question is a bit similar to Can the new Mapbox Vector Tiles be ...
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1answer
186 views

How can I allocate a $rownum in reverse order in QGIS?

How can I allocate the $rownum value in reverse order in QGIS? I have a created a grid layer to use in an atlas and the ID allocated is from top left to bottom right - which is what I want if I want ...
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2answers
356 views

Different definition of EPSG:3857 in GeoTools and QGIS

I want to do some checking if my point lies in any of the polygons defined in shapefile. So, I thought that I will determine CRS from shapefile (created in QGIS), and use it for transformation (where ...
2
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1answer
175 views

QGIS 2.8 topological editing creating vertices

When using the node tool with topological editing enabled on a group of multiple lines, double clicking sometimes doesn't create new vertices. Instead, the line segment gets selected. When this ...
3
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2answers
131 views

Loading Grass 7.0 vectors in QGIS broken?

Running QGis 2.8.1 in Win7 (64bits), installed through OSGEO4W. When trying to load a Grass 7.0 vector file in QGis, the program will simply crash without any notice. I can load old Grass vectors ...
2
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1answer
179 views

New filter expression QGIS 2.8

I try the new filter expression with QGIS 2.8. I want to filter only the selected objects on a layer in my map. My expression is: import processing from qgis.core import * vlayer = ...
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2answers
470 views

“ImportError: no module named qgis.core” in standalone app

I am developing a standalone app (in Windows) using libraries from QGIS. When I run the script in cmd, I get the ImportError: no module named qgis.core. I read in several posts that I need to ...
2
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1answer
255 views

Go through items in a composer legend (QGIS 2.6)

I'm trying to develop a plugin in QGIS 2.6, which opens a composer, add a map and a legend, and (among other things) adjusts the legend. Is there a way to go through items in a composer legend with ...
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1answer
63 views

How to georeference two pictures that do not have crs in QGIS

I would like to take aerial pictures of my research plots an caculate NDVI and NDWI. How do I do that in QGIS?
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2answers
247 views

qgis: how to use 'max()' in an expression

I wanna make a rule-based style on the maximum value from a field. I set my expression like: max("fieldname") It returns every value instead of only the maximum one. Can anyone tell me the richt ...
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0answers
68 views

QGIS actions - get currently selected attribute column (with python?)

I'm trying to open files dynamically through actions. A simple example would be: Action name: OpenLink from PyQt4.QtCore import QUrl; from PyQt4.QtWebKit import QWebView; myWV = QWebView (None); ...
2
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1answer
388 views

How to select lines/polygons in QGIS CAD tool?

I'm intending to create parallel and orthogonal lines by using the CAD tool in QGIS. For each tool there is a button to select the feature before executing the tool. But though I fixed all the ...
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2answers
189 views

Does QGIS data work in Esri CityEngine?

Does QGIS data work in Esri CityEngine? I have a copy of CityEngine Basic and imported a shape file which have the street network and lots. Without ArcGIS I can't open data which have building ...
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1answer
77 views

Is there any topology handler in QGIS?

When importing autocad maps, sometimes topology will be chaos, this need to be amended. And when I add new topology in QGIS, how to save that to the postgreSQL? Is these functions included in QGIS or ...
2
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0answers
41 views

Is it possible to have a locked/different first page with QGIS Atlas printing?

It is possible set the first page of a QGIS Atlas different to the other pages? For example I want to create an Atlas document where the first page has a text introduction and a general map (not ...
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1answer
86 views

What are the wider capabilities of the QGIS atlas functionality? [closed]

Given that it is already understood that the QGIS composer atlas function makes it possible to print separate pages based on a 'coverage' layer, what basic range of functions/outputs can be achieved ...
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1answer
54 views

Trouble updating attributes of a layer based on another layer's attributes if features intersect in python, QGIS

I am trying to assign attributes from features in one layer that intersect features in another layer. When I run my code, I do not get an errors but it does not update the attribute field as I am ...
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42 views

How do I trick QGIS's map composer into chopping off the 000's in UTM coordinates?

In QGIS 2.8 (ubuntu), you can create a map with ticks and labels. I want the first two digits to be smaller sized, the next 3 to to be normal sized, and hide the last 3 digits. QGIS does not offer ...
1
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1answer
44 views

Making centeroids for vector grid

I need to add polygon centeroids to vector grid but I cant... i have output grid like polygon, but i cant choose layer to make centeroids I need it for R studio and pollution model of city, thx for ...
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0answers
66 views

QGIS Polygonize (GDAL) problem - Null value in attribute

Is it possible to use Polygonize in QGIS (GDAL) so that a line shapefile is converted to a polygon shapefile with an attribute(s) in the line file carried into the polygon file. I am trying to build ...
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2answers
193 views

How to get a layer that is not active with PyQGIS

I want to retrieve attributes of selected objects on a layer with PyQGIS. All example I see is for the active layer: vlayer=qgis.utils.iface.activeLayer() selected_bf = vlayer.selectedFeatures() ...
11
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1answer
776 views

HERE background maps in QGIS possible?

The OpenLayers plugin for QGIS allows one to add background maps from various sources to the data frame. These sources include OSM, Google, Bing, MapQuest, and Apple. However, Nokia's HERE Maps, is ...
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42 views

How to overwrite/change attribute values with QspatiaLite in qgis 2.6

I tried to work on the "tbl_datum_transform" table which is included srs.db data file. Just to let you know... i try to fill in the ntv2 - BETA2007 grid. How can i fill in something in the ...
2
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0answers
98 views

QGIS WMS Server

I have successfully installed QGIS Server on Ubuntu 10.04 Lucid. The QGIS project file I want to publish as WMS was created with QGIS 2.6.1 The data is stored in shapefiles, the GetCapabilties request ...
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405 views

Error loading plugin photo2shape even after installing exifread module

I am new to any GIS and have been exploring QGIS software so we can eventually apply this technology to our agency. I am trying to figure out how can I install the photo2shape plugin successfully. ...
0
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1answer
72 views

How can I get 3 different maps in one print composer?

Im using 2.6 and am struggling to get 3 different maps in one print composer. Better explained, 1 map with the county, the 2nd closer viewed with the town and the 3rd with the actual woodland. Its for ...
0
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1answer
66 views

QGIS - Labeling with expressions

some polygons in my map have a "name" (but no "capacity") and some have a "capacity" (but no "name") and some have both. I want to label the polygons with the "name" and the "capacity". Therefore I ...
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0answers
68 views

Locating Coordinate Reference System Selector on QGIS [closed]

I downloaded the latest version of GQIS last Friday(6/3/15). I can't locate the Coordinate Reference System Selector. I have tried clicking settings, custom CRS, add CRS, but can't find a way to ...
3
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2answers
249 views

Calculating unique ID value for a field in QGIS using python

I am trying to calculate a unique ID field for a vector layer in qgis, using python. I found some code to calculate attribute values, and tried to increment the value in the expression, but it doesn't ...
2
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2answers
121 views

Trouble with heatmap plugin in 2.6.1

When using the heatmap plugin, I am getting some insanely large numbers for the cell size field when setting the radius to 5000. I know that rows and columns are related to cell size x and cell size ...
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1answer
178 views

Exploding multipart features in qgis using python [duplicate]

I want to explode a multipart layer to singlepart in python. I see through the qgis gui there is a way to do it under vector--geometry--tools--Multipart to Singleparts.. which does what I need, I just ...
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0answers
22 views

Merge CSV file to Vector Layer using common attributes in QGIS python scripting [duplicate]

I have a vector layer and a delimited text (csv) file -- they both have the common attribute attribid -- how can I add the columns of the csv file to the vector layer merging on the the attribid key ...
2
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1answer
643 views

wine + LAStools in QGIS 2.8.1, Ubuntu 14.04

I can't get wine + LAStools to work in QGIS 2.8.1 (ubuntu 14.04). I only get the 22 open source functions that comes with QGIS. Outside qgis wine + LAStools works fine. My guess is that I am not ...
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0answers
288 views

Installing PostGIS Layer Viewer for pgAdmin III

I have difficulties installing pgAdmin's plugin PostGIS Layer Viewer. The official repository on GitHub gives this Web site for install procedure, then the former site gives this Web site for ...