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

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3 views

Finding the boundary polygon from a set of gridded points (no hole)

Let us consider a set of a 2-D points (longitude, latitude) each of which is centre of square grid (intersect point of the diagonals of the square). I try to make you understand what I want to do in ...
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0answers
9 views

seeking help to build QGIS from source code with microsoft visual C++ on windows 7 [on hold]

how to build QGIS with Microsoft Visual C++ 2010 Express Edition on windows 7
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0answers
6 views

How to select the features by freehand in qgis using python programming

I have one polygon layer with 10 features. when i draw a line by free hand on the polygon layer it has to select the features. But when i am using qgis.utils.iface.actionSelectFreehand().trigger() ...
2
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0answers
18 views

Qgis2Threejs returns empty page

When i try to make 3D scene from DEM with Qgis2threejs it creates a empty html page. I also try to make 3D thematic map from shapefile with the same result. I have also check my browser and it ...
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0answers
13 views

QGis measure tool does not continue to measure within point symbol

We are using QGIS more and more, however, today a colleague noticed something strange when using the measure line tool. We have point features and different symbols of different sizes and colors are ...
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0answers
15 views

Efficiently generate Voronoi layers in qgis via Python

The following python commands both appear to function when called in qgis 2.6 to generate Voronoi diagrams: processing.runalg("qgis:voronoipolygons", pointLayer, 1, None) ...
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0answers
27 views

Spacing a set of points

I have a shapefile of a set of points that I want to space out. I DO NOT want to do this using line interpolation as I run the risk of placing a point where there wasn't one before. I can load this ...
1
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1answer
30 views

How to set the QGIS display to show decimal degrees?

Using QGIS 2.6.1 Brighton. I am trying to set the CRS for the project to display Decimal Degrees, where it is defaulting to Feet. I can change it in the Properties Dialog, but it does not change it, ...
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1answer
15 views

qgis : how to merge attributes of points and lines

I have a point vector-layer and a line vector layer. All points of the point layer are positioned on the lines (railway lines) of the line layer. I would like to add the attributes of the line layer ...
2
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1answer
25 views

Merge multiple bus stops with same name

my question is similar to this one, but it's not answered sufficiently: How to merge points (bus stops) in QGIS manually or programmatically? I have OSM-transit data with bus stops. Some stops have ...
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0answers
3 views

Unable to execute the algorithm using SAGA LS factor

I tryed to calculate the LS Factor at SAGA, using a slope raster and the area raster, both at the same EPSG, and the error:Unable to execute the algorithm the error means something with the coordinate ...
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0answers
5 views

Error when using r.watershed

When i am calculating LS Factor using Grass r.watershed the error "Raster map or group not found" (image below) keeps turning on. I don´t understand why this error happens if i am using a elevation ...
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0answers
9 views

Manifold GIS Scripting/Queries — query a web page and scrape page source?

I'm using Manifold v8.0 to process some data. The process involves some scripting and querying, but one step currently requires me to go to a website, enter some data into a form, read the results of ...
2
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0answers
7 views

QGis - WFS and joins

I'm trying to figure out whether it's just me, or if I'm forgetting a setting. I have a shapefile which I make available for WFS-requests. Now I added a join (to a MySQL table). I tried playing ...
1
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1answer
16 views

Adjust Fill style behavior QGIS

Does anyone know how one can change the Fill style option in QGIS? I need to use a diagonal pattern that does exist, but I need to adjust it. I have a cartography specification that defines the ...
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0answers
11 views

How to show features in Layers panel in QGis?

I'm new to Q-Gis, so forgive me if that's an obvious question. How can I see the features in Layers panel in QGis in a nestef form? Thanks! Dani
2
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2answers
30 views

QGIS keyboard shortcut to launch a 'Select by expression' query

I can't find if it is possible to launch a 'Select by expression' query (not to open the dialog) with a keyboard shortcut. I can't find this option in the Settings > Configure shortcuts list... If ...
3
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1answer
33 views

How can I find the version of a toolbox used in QGIS

I am using QGIS 2.6.1 Brighton on Xubuntu. The QGIS-install comes with several default toolboxes. Orfeo Toolbox for image analysis is one of them. How can I find out which version of the Orfeo ...
2
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1answer
40 views

Run processing toolbox outside QGIS in standalone app

I am developing a standalone app in Python, using QGIS libraries including processing algorithms. I am developing in Linux environment and I put the libraries in a folder. Also I put the processing ...
3
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1answer
15 views

How to shift a raster in QGIS?

I'm looking for a tool or a plug-in for QGIS that would allow me to shift rasters to new coordinates. An equivalent of ArcGIS' Shift tool would be the best option. I know I can edit the world file ...
2
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1answer
20 views

QGIS : Disable a line in 'Select by expression' dialog

I would like to disable some lines in the 'Select by expression' dialog (QGIS 2.6) but I can't find whether it is possible or not, and if yes, how to achieve that. I have tried several characters ...
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1answer
17 views

Creating Stream Order

I'm new user of this software, please can somebody guide me, how to calculate stream order in QGIS or GRASS GIS, step by step.... mean commands and how to calculate watershed in this.
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0answers
15 views

Connect two contour line with calculated line lenght

Is it possible to make plugin for qgis like PEGGER for arcview 3.2? Problem is, how to make path over contour lines with a grade in percent Formula is: K= e*100/G*M ; K=10*100/0.08*10000=1.25m K- ...
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0answers
39 views

Calculating vector area in QGIS

I have calculated a viewshed (ZVI) in OpenWind and opened the raster in QGIS I have then converted the raster to a vector When I open the attribute table there are 4682 rows (features) and there is ...
1
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1answer
35 views

How to create a text file containing layer names in QGIS?

My QGIS ToC contains layer groups and some layers that do not belong to any group. I would like to create a text file containing the name of those layers that do not belong to any group. Is there an ...
3
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23 views

QGIS algorithms do not work on copies of shapefiles?

I'm using QGIS 2.6.0. I'm trying to run various algorithms such as "SAGA/Shapes-points/remove duplicates" & "SAGA/Shapes-Grid/Add grid values to points" through the sextant toolbox. When I run ...
2
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1answer
22 views

Error converting a raster to polygons

When I am converting a raster using the polygonize tool, I get this error: ERROR 4: 'C:/Users/Vitor/Desktop/Cartografia EE_Portimo/COS RASTER/cos_raster_reeditada.tif' does not exist in the file ...
1
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1answer
42 views

How to automatically create 10,000 sets of random points for further analysis in QGIS?

I'm using QGIS and would like to know if I can automate generating multiple sets of random points and mean distances? I have a data set consisting over 600 coordinate points for Mistletoe across ...
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0answers
11 views

How to relate data values from two raster layers?

This is my second posting ! 1 Background I have a number of ASCII files containing a set of single values X, each set in a 1km x 1km grid – the start of each file looks like this: NCOLS 700 ...
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13 views

How can i perform area calculations in a raster file?

I would like to know if is possible and how can i calculate all areas or parts of it in one raster? Can i do it using the raster calculator? All help is appreciated, Best regards
3
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1answer
43 views

How to display OSM relations (in QGIS) from osm2pgsql populated PostGIS DB

I have a PostGIS DB populated with OSM data (osm2pgsql, standart.style). Now I would like to display a hiking trail (http://www.openstreetmap.org/relation/51855). It would also be fine, if I just ...
5
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1answer
243 views

Is it possible to have dynamic layer names in QGIS project?

I have a QGIS project with layers, based on PostGIS SQL queries that use current date. Since the data in the database changes, these queries return different data every new day. Is it possible to ...
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1answer
23 views

Tools to export shps from Oracle database

What open source tools could be used to export shapefiles from an Oracle database. I have tried using QGIS but it does crash way too much.
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0answers
15 views

How to get the same cell size after and before been rasterized [duplicate]

The following information were used for rasterization of the land cover of Nigeria but got different cell sizes. The input cell size and the measured cell size of the rasterized are not the same. ...
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1answer
30 views

Got different cell sizes from a rasterised data

I'm trying to rasterize the Land cover data of Nigeria which was obtained from FAO database. During the process of rasterizing the land cover data, I used the following information which gave ...
2
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0answers
19 views

Why does my “Zoom to selected rows” Shortcut not work in QGIS 2.6.0?

I´ve changed a shortcut, in this case "Zoom to selected rows". But now it stopped working. The new shortcut never worked and the originally as well is not working now. The icon gets activ when doing ...
4
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1answer
38 views

QGIS batch shp transform

I have a large number of shape files in OSGB (EPSG:7405), with no .prj file that I would like to convert to WGS84 (EPSG:4326). Can you let me know if this is possible in Qgis and, if so, how, and, if ...
1
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1answer
31 views

Is it possible to create tiles with transparent background using Qtiles?

I had created the tiles from shapefile using qtiles plugin in QGIS and that shapefile layer is a label layer created using MMQGIS plugin. But the thing is I want that tiles with transparent ...
1
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1answer
11 views

Open and split a 4 channel RGB picture

How can I split an 4 channel rgb pic in qgis? With the value tool I can see 4 channel. I tried to use the RGB to PCT tool but I always get an error (File "C:\PROGRA~1\QGISBR~1\bin\pct2rgb.py", line ...
1
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1answer
27 views

How to compute tabulate intersection in QGIS?

I have a base layer of census data in census tracts (polygons). I'm looking to intersect those tracts with a buffer layer but I only want to include those census tracts whose area is over 50% within ...
1
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2answers
50 views

Merging shapefile layers not working in QGIS?

How do i merge different vector layers in to one shapefile layer In QGIS version 2.6
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0answers
13 views

If statement using QgsRasterCalculator

So in the sequence of my previous question (Can't use Raster Calculator with two different rasters), I am stuck again in my project. With my source rasters, I created 3 different outputs using ...
2
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0answers
22 views

QGIS raster data from vector and raster files

Excuse me if my GIS terminology is a bit shaky, and for the length of the post, as I am a complete beginner to GIS and this is my first forum post. I am using QGIS 2.6 32bit on Windows 7. 1 My data ...
2
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0answers
26 views

QgsRubberBand with holes

I tried to create a QgsRubberBand object with holes, but failed: rb = QgsRubberBand(iface.mapCanvas(),True) geom = QgsGeometry.fromWkt("POLYGON((0 0,4 0,4 3,0 3,0 0),(1 1,3 1,3 2,1 2,1 1))") ...
3
votes
3answers
76 views

Alternative to OpenLayers plugin for QGIS?

Are there any alternatives to OpenLayers plugin to have Google / Bing maps for QGIS projects? I need an high quality cartography (both aerial and street view) but OpenLayer plugin do not allow to ...
1
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1answer
29 views

How to make rectangle selection on QgsMapCanvas?

I have this code for create and open raster map: if(QFile::exists(rasterFileName)) { QFileInfo myRasterFileInfo(rasterFileName); m_pRasterLayer = QSharedPointer<QgsRasterLayer>( ...
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0answers
8 views

Transparency on black/white raster after clipping in QGIS?

I'm new to this forum and QGIS. I'ld really appreciate it if you could help me with my problem, since I couldn't find any solution online but people experiencing the same issue. It seems as if this ...
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0answers
25 views

Soils sampling. How to make polygons from interpolated points?

My goal is to make a shape file with polygons for variable rate fertilizer application within a farm field. I have a point shape file with soil sample values (pH, P, K and so on) and a line/polygon ...
2
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1answer
59 views

Use 2 different symbologies on the same feature QGIS

I have data symbolized with different categories Each category has a field for different symbology style like the table below. Is it possible to visualize the same category of data with in ...
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2answers
57 views

How to add 2 layers in qgis and display them at the same time

I added 2 layers in qgis using python but only one layer is shown on canvas. After clicking (anywhere on the canvas) both layers are displayed. layer = ...