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

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Help with georeference: imported Tif is dark gray

Using georef on QGIS 2.6 I import a TIF file, and expect the import to show an image that has black lines on a white background (with some other colors here and there). the file, 96MB, imports, but ...
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6 views

QGIS procedure for Multidirectional, oblique-weighted, shaded-relief?

Is QGIS capable of the multidirectional, oblique-weighted,shaded-relief method described at http://pubs.usgs.gov/of/1992/of92-422/of92-422.pdf ? If so, what are the steps necessary in QGIS to ...
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1answer
29 views

Fill polygons via data-defined pie charts

I am trying to summarize my polygons by each's distribution of some variable. To couch the discussion, let's say we wanted to summarize the demographics of each county (of a small state) by it's ...
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0answers
14 views

Custom QGIS 2.6 map tool - mouse click and release issue

I have create a custom map tool for QGIS 2.6, implementing a canvasReleaseEvent and canvasPressEvent. I can't though get the signals to work on one single mouseclick (I have to click twice). My map ...
2
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1answer
19 views

How to display QGIS plugin panel “OSM place search”?

It is possible to hide the panel for the experimental QGIS plug-in 'OSM place search' - but the panel is not listed (to re-display) under the menu item View | Panels. How can it be re-displayed?
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21 views

How to deal with contour error “Exception encountered: invalid index”

I have include vector layer using postgis database with filter(data between two dates) it work fine but after adding when I trying to make a contour from it I get error Exception encountered: ...
3
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0answers
17 views

How to display features only if labels are displayed?

In my maps there are several point layers, and each layer has a different labelling rule and priority. Sometime the point density is too high and the labelling engine is not displaying some labels, ...
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1answer
12 views

Change detection between two classifications in QGIS?

I have two raster classifications. They have the same number of classes which use the same ID (each class has a unique ID). I would like to get information on the changes between classes i.e., class 2 ...
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1answer
18 views

How to convert total station data (coordinates) to 3D model? [on hold]

i have my coordinates in .csv format and i want to convert it to a usable 3D model. How do i go about this or what software can i use to achieve this?
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2answers
14 views

QGIS upper round in field calculator

I need to to in the field calculator the following calc: toint(Field1 / 25.0) but i need to round the result to no decimal places but upwards. Exmaples: If 17/25 result should 1. If 25/25 result ...
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0answers
11 views

How to equally space points in a line using QGIS? [duplicate]

How do you place points in a straight line the same distance from each other in QGIS? Thanks
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3answers
19 views

QGIS: Get data in raster DTM from vectorpoints

I have a vector layer of points. Can I get an output from a rasterlayer which contains DTM-values (height) determined by my points placement?
3
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2answers
26 views

Send signal when attributes modified - QGIS 2.6

For a QGIS 2.6 python plugin, I am trying to send a signal when an attribute value is changed (values for an existing feature are updated or added and the attribute form dialog is accepted). This ...
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2answers
26 views

How to create an image of mean values from multiple NDVI images?

I have downloaded MODIS NDVI images of 12 months. I would like to create just 1 image with the mean values. I tried using IDRISI's 'NDVI compositing utility', but I get an error. Is there a way to do ...
2
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0answers
23 views

Shapefile layers in QGIS don't display unless I zoom out

I have two shapefile layers in a Qgis project that have problems with zooming. One is a line I copied/pasted in a new layer from a set of height contours and the other one is a polygon layer I created ...
1
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1answer
17 views

Why use QgsFeatureRequest() when iterating?

I am unclear on why one should use QgsFeatureRequest() when iterating over a file’s features. Let’s say I would like to print out all IDs in my currently active dataset. Now, most examples will ...
3
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2answers
25 views

Qgis - Projection Problem with EPSG:2272

I work in both Qgis and ArcGIS. Most of my data has been created using ArcGIS and all of my data should be in the EPSG:2272. When I add my data to Qgis, it does not recognize my projection and gives ...
3
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1answer
38 views

How to always disable the “add saved file to map” checkbox in Save as …?

I often use the "Save as.." dialog and just want the exported geojson file there. But he always enables the checkbox "add saved file to map". I really dislike it that way and it does not make any ...
4
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2answers
40 views

Adding Eastings and Northings as attributes automatically to a point layer in QGIS

I have a point layer that I am adding to and am working in British National Grid. Two of the columns are Easting and Northing. When I add a new point I want these two columns to be filled out ...
4
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1answer
22 views

Start QGIS with virtualenv Python

is there any means of telling QGIS to use a different Python installation than the default, system-wide one? E.g. use some virtualenv Python /myvirtualenv/bin/python instead of /usr/bin/python? ...
2
votes
1answer
20 views

Visualising a raster PostgreSQL table in QGIS

I have imported a raster tif image into PostgreSQL with this command: raster2pgsql -s 32643 -I -M filepath.tif -F -t 100x100 public.databassename > filepath.sql And imported the output SQL file ...
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0answers
25 views

3D interpolating

Our final year project domain is soil contamination modeling. We collected soil samples at the depths of 0.3 cm ,0.5cm , 1cm , 1.5 cm in about 25 locations. We considered 8 contaminants- p h, sodium, ...
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0answers
18 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
27 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() ...
4
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1answer
35 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
26 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
25 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) ...
3
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3answers
81 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 ...
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2answers
39 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, ...
2
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1answer
21 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
votes
1answer
36 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
6 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
14 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
13 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
10 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
18 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
12 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
34 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
45 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
68 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
votes
1answer
19 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
votes
1answer
21 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
19 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.
1
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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
42 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
vote
1answer
37 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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0answers
27 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 ...
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1answer
23 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 ...
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1answer
44 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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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 ...