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Questions tagged [qgis-2]

Version 2.x of QGIS (previously Quantum GIS)

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4
votes
0answers
355 views

Rule-based labeling and the Data defined placement options are not working together (QGIS 2.12, 2.14)

After setting "Rule-based labeling" to my layer (new feature since QGIS 2.12), my data defined labeling is not working any more (see labeling tools on the right side): Going back to "Show labels for ...
4
votes
1answer
4k views

How to remove selected elements from a QGIS legend?

I'm working with a QGIS project with a number of layers. When assembling a printout all visible layers are automatically added to the legend: I would like to exercise some control over the legend ...
4
votes
2answers
830 views

Performing addition in QGIS Raster Calculator?

I am using QGIS 2.6 on Windows 7. I have generated two rasters from vector layers. They cover the same extent and have the same projection (Irish Transverse Mercator) and cell size (5m x 5m). I have '...
4
votes
2answers
311 views

Easier calculation of a surface using QGIS

I'm looking for an easier way to calculate the surface on QGIS: My project CRS is in Lambert93. Currently, when I'm calculating a surface using QGIS, when the surface seems wrong, I always have to: ...
3
votes
1answer
199 views

Error while changing the symbol of a layer in QGIS in plugin

I am trying to add a feature then trying to change shape and size of feature like below:- layer = QgsVectorLayer('Point?crs=EPSG:4326', 'point' , "memory") pr = layer.dataProvider() pr.addAttributes([...
3
votes
1answer
81 views

Multiple layers auto-updated when one of them is modified

I just discovered this post and I found what I searched here. But I was wondering if there was a way to have multiple layers (let's say l1, l2, l3, l4) being updated automatically when you change ...
3
votes
0answers
973 views

How to rotate symbols in QGIS

I have a vector symbol that I am using rule based style with. In the Rule properties tab I click on the SVG marker and change the "rotation" which is a field I have made to handle to the rotation ...
3
votes
3answers
148 views

Automatically populate r.reclass rules based on table values

In QGIS I have a raster map showing land, snow and cloud zones, having resp. pixel values 1, 2, and 3. I extracted the mean altitude values (in m) of each zone on the basis of an underlying DEM and ...
3
votes
1answer
368 views

QGIS 2.18 : Choosing path of file for Python init function

I'm using a custom feature form for QGIS 2.18 (custom .ui file + custom Form.py file containing the Python init function used by the form). I would like to be able to put the .ui file and the Form.py ...
3
votes
2answers
875 views

Georeferencing PNG with transparency via gdal produce “green pixels” in QGIS?

This is just intriguing while not blocking my way, but I wonder what is going on and would like to get feedbacks from more experienced users. 1) Given a trans.png file (1.1MB) looks good and ...
3
votes
1answer
91 views

How to update the Layer Tree View after changing the color ramp in PyQGIS?

After changing a raster style/color ramp (wich is working properly to define the class colors and values) using: layer = processing.getObjectFromName('NDVIrec') provider = layer.dataProvider() ...
3
votes
4answers
2k views

Why does QGIS 2.4 crash at every shutdown?

I am using QGIS on two Win7, 64 bit machines for years. After upgrading to QGIS 2.4 it crashes on both machines at every shutdown with the message "Minidump...". The crashes occur independant of what ...
3
votes
1answer
1k views

SAGA algorithms don't work in QGIS 2.8

when I have installed recently QGIS 2.8 and, since then, SAGA algorithms don't work. Apparently, the algorithm runs well (any error is showed while it is executing the algorithm), however, there is ...
3
votes
1answer
186 views

How can I get the default zoom level to work in QGIS for geography types?

Create a table like this, and then add it as a layer to PostGIS. It has one simple geography, a line. CREATE TABLE foo AS SELECT ST_GeogFromText( 'LINESTRING(-122.27172 37.80345,-122.27172 37.81549)...
3
votes
1answer
9k views

QGIS polygonize error 4 “file does not exist in the file system”?

When I try to convert a raster DEM (in .asc or geotiff format) to polygons I get the error below: ERROR 4: `Y:/GIS/oversvmmelser/tmp/out.tif' does not exist in the file system, and is not ...
3
votes
2answers
1k views

How to set NULL as default value for a date field in QGIS 2.4?

In QGIS 2.4, i am unable to set the default value as NULL if i have not updated any value on date fields. Its automatically taking the current system date. I am expecting to set the default values(...
3
votes
1answer
807 views

How to set drawing style for QgsRasterLayer in QGIS 2?

I am using PyQGIS. In QGIS1, I can use: rlayer.setDrawingStyle ( QgsRasterLayer.PalettedColor ) but In QGIS2, I got some errors. I follow pyqgis developer cookbook, put some demo scripts in ...
3
votes
1answer
712 views

Whats wrong with the difference tool QGIS 2.14.1?

I want to get the difference between two poligons. I compare the result from Arcgis erase tool and QGIS difference. ArcGIS give me that I want, but Qgis don't. Why? QGIS not only give wrong ...
3
votes
1answer
2k views

QGIS's Select Features tools only work occasionally

I'm hoping someone can help me work out whether there's something I'm missing here or whether QGIS's Select Features tools are just really buggy. I have a variety of polygon layers from shapefiles ...
3
votes
1answer
1k views

QGIS: How to change symbology of a continuous raster to discrete with unequal intervals?

I'm new in QGIS and currently trying to convert my ArcGIS-layers into QGIS. One of these layers is a slope gradient raster. I want to change the symbology so that a specific rang of gradients will ...
3
votes
2answers
805 views

Any QGIS 2.0 updated RPM for Fedora?

I'm very excited about the new release of QGIS (2.0), and would like to install it on my Fedora 18 machine. I couldn't find any relevant RPMs, and the documentation on the QGIS main site for Fedora is ...
3
votes
1answer
938 views

How to bring feature selection into Printing Composer?

I'd like to make maps of Finland's municipalities. Our National Land Survey provides data I can make into a Shapefile, and when a municipality is selected in QGIS/Identify Features, three different ...
3
votes
0answers
162 views

Raster calculators in SAGA return incorrect results

Here's a sample of my dataset (one cell) with 28 different raster values, representing 28 individual Float32 rasters with identical parameters. 0.0000264434, 0.0049953502, 0.0007529828, 0....
3
votes
1answer
535 views

Spatialite WITH clause issue

I've encountered an issue: when I try to execute in Spatialite_GUI query that contains WITH clause I get SQL error: near "with": syntax error. Also WITH unlike SELECT and other keywords is not ...
3
votes
2answers
1k views

Where are QGIS application setting file(s) stored?

I have some application settings (Windows/QGIS v2.0) that I would like to pass to other users (such as those settings defined under Settings menu>Options>Rendering tab). In ArcGIS they are stored in ...
3
votes
1answer
830 views

Can QGIS 2.8 load WMTS layers?

I'm having a bit of an issue loading a WMTS into QGIS 2.8. The application can connect to the WMTS, correctly identify the layers that are available and load the layer into the layer pane. However, ...
2
votes
0answers
313 views

Get signal on edited feature?

Regarding my pyqgis plugin 2.2 , I've implemented signal on a vector layer event successfully. For instance, whenever i create a new feature, i can read a new basic message appeared via QGIS logging ...
2
votes
1answer
1k views

How can I lock the scale when panning?

I'm just wondering if there's any way to easily lock the map scale when panning etc. For example, suppose I set the scale to 1:100,000 - panning with the mouse will then alter that slightly, which can ...
2
votes
1answer
46 views

Number each value in each section due to other value

I'm working with map of plants in garden. This garden is divided into about 40 sections. Plants of one species have their number for example every Scots pine is 12 and every Common oak is 15 in field "...
2
votes
1answer
191 views

PyQgis api returns wrong layer CRS

I have shape vector layer in ESPG:3859 CRS. I try to get layer crs layer.crs.geographicCRSAuthId() but method always returns EPSG:4326 no matters which CRS I chose in layer properties. .qpj file ...
2
votes
1answer
3k views

How to edit a vector layer extent?

I'm working on QGIS 2.2, and I would like to make a vector layer extent bigger (thus the clip option is not suitable) to match exactly my mask layer extent. I would like the new added area to be empty....
2
votes
1answer
236 views

Merging multiple bus stops with same name using QGIS?

My question is similar to Merging points (bus stops) in QGIS manually or programmatically?, but it's not answered sufficiently I have OSM-transit data with bus stops. Some stops have two or more bays ...
2
votes
1answer
2k views

Remove unwanted black area around clipped raster in QGIS 2.18

Following on from Remove white background in Raster in QGIS When I choose the unwanted value - in my case I want to remove black area around the clipped raster - I write 0 as the unwanted value, but ...
2
votes
1answer
183 views

Decimal Degree data erases itself between edit sessions in QGIS

I have a shapefile with point data. I calculate the $x and $y of the points successfully I save the changes and close the edit session. Once I reopen the attribute table, the data after the decimal ...
2
votes
0answers
737 views

QGIS 2.4 Processing (Zonal Statistics) error [closed]

In QGis 2.2 all my models (processing model builder) are working fine. When I start the same models in 2.4 I get errors like this: Prepare algorithm 5: Zonal Statistics Running Zonal Statistics [...
2
votes
1answer
107 views

Creating different label styles for different polygon classes using QGIS?

I'm new to QGIS 2. I have a polygon shape with two classes, and I want to set different labeling style and different "Scale-based visibility" but I don't get how the expression works.
2
votes
2answers
555 views

Fast way to merge 8000 raster?

I have to merge almost 8000 rasters (TIF). I tried using Mosaic To New Raster in ArcGIS 10.3, but it's processing really slowly and crashes quite often. Is there a faster (or more stable) way to ...
2
votes
1answer
353 views

Why do I get a NameError for QDomDocument when attempting to programmatically load a template in the QGIS Python console?

I'm trying to work through this answer in the QGIS (2.14) Python console to understand, ultimately, how to iterate over layers and print them with a template. When I run the following code block. I ...
2
votes
1answer
1k views

Grid and Graticule in QGIS Print Composer in QGIS 2.8

I'd like to add a grid in the print composer. The problem is there is no visible option like it was in previous version. I mean I'm looking for an option "Show grid?" like in the picture below. I can'...
2
votes
2answers
895 views

Setting SAGA folder for QGIS with OS X for macports install?

I am trying to get the toolbox to work in QGIS 2.6, but I keep getting an error message that SAGA is not properly configured. After much digging, I finally found I can set the SAGA folder in ...
2
votes
1answer
2k views

QGIS 2.12 & Ubuntu 14.04 SAGA installation not found

Installing QGIS 2.12 on Ubuntu 14.04 from the debian trusty ppa. Upon opening QGIS I notice the following error under the Processing tab: Problem with SAGA installation: SAGA was not found or is not ...
2
votes
2answers
173 views

Calculating point layer values within polygon features in QGIS 2

There are two layers polygon BereichBerechnung with a field "Are_Number" points EW2017 with a field "EWjeAdr" In QGIS with a Virtual Layer, I want to calculate the sum of the field "EWjeAdr" for ...
2
votes
1answer
755 views

How to rollback the committed changes in the Vector Layer in qgis

I selected few features in the vector layer and updated the field. But I want to rollback the changes committed to the vector layer. How can I do that in QGIS? I have used the following coed: layer....
2
votes
1answer
619 views

How to show in a custom QGIS form the feature and/or geometry info?

I need to show point coordinates on the from dialog used to edit the attributes of a point.. I see that in the formOpen the dialog receives a layerId and a featureId, but no iface object, so how can ...
2
votes
1answer
371 views

Error when writing SHAPE to WKT with pyqgis and QGIS 2.14

It seems the answer linked here doesn't work in latest version of QGIS 2.14 layer = QgsVectorLayer("/home/reyman/Projets/cours/coursPython/pyQgis/shape/passages/passages.shp", "passages", "ogr") if ...
2
votes
0answers
92 views

Prevent QGIS from loading WMS services when opening project

I have a QGIS project with several hundred WMS and ArcGIS MapServer layers. Every time I open the project it starts loading them one by one, which my take quite a while. Is there a way to prevent ...
2
votes
1answer
852 views

Erode pixel areas in QGIS

I try to resize Pixel segments exported from eCognition. The goal is to erode the segments for one pixel of the boarder. So for example if the segment is 30px x 30px the result should be a new area ...
2
votes
1answer
243 views

GRASS in QGIS - ' Cannot read raster map region' (running r.lake.xy)

I want to use the GRASS function r.lake.xy on a DEM that I have. I load the DEM raster into QGIS, it is not georeferenced. Then I create a New Mapset. I set Projection Not defined. I either leave the ...
2
votes
0answers
406 views

Using SVG file to fill polygon using QGIS- problem

I try to fulfill polygon with SVG file (which created with inkscape) but when i load the file into QGIS by this way: i get polygon layer with no symbology: Now, i red Using SVG from Wikipedia to ...
2
votes
1answer
2k views

QGIS 'Difference' tool return empty layers

I've been using QGIS's difference tool to create some new layers. All was going well until I hit a number of layers which return a blank layer with no features when I use the difference tool. The ...