Python bindings for QGIS.

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PyQGIS: intersection of one node layer with two polygon layers

I´m new with the use of PyQGIS and I´m working in a problem applied to a water supply systems modelling, where I need to distribute the water demand in about 5000 nodes (network junctions). I´m ...
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1answer
18 views

How to keep live update coming from a WMS

I'm using a WMS that contain weather radars that is update every 10 min. I would like to know how to keep the map updating every 10min. I tried: from PyQt4.QtCore import * timer = QTimer() ...
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18 views

How do I change the pixel values of raster data from QGIS python plugin

I have been trying my hand at a QGIS plugin. The plug in reads raster layer data into an array, pipes the data to a C++ program, does processing over there, and pipes my results back. After a couple ...
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33 views

How to incorporate QGIS custom widgets into plugin? [duplicate]

Developing a plugin with Qt Designer for QGIS 2.14.1-Essen on Windows 7 and having trouble inserting the QgsCollapsibleGroupBox widget. I receive the following error: ImportError: No module named ...
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2answers
30 views

QGIS Segmentation fault when manipulating QgsGeometry

So I am running QGIS 2.8.1 on Ubuntu 14.04. This following problem is happening in my script, but also occurs directly in the QGIS python console: lay = iface.activeLayer() lay.featureCount() 1L ...
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1answer
133 views

Setting a default value in a QGIS field

I would like to add in a layer's field a default value. I mean, every time a new feature is created, that field would be automatically filled with the default value. In my case the default value ...
3
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1answer
27 views

Errror using the Simplipy QGIS plugin: 'QgsRasterLayer' object has no attribute 'selectedFeatureCount'

I am adding a raster in QGIS 2.14.1 and get this new error: AttributeError: 'QgsRasterLayer' object has no attribute 'selectedFeatureCount' I am not programming, just using a QGIS menu. I am using ...
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1answer
25 views

refresh programmatically created composer

I am trying to create a composer using pyqgis. Everything works as expected. The only difference compared to the manual creation of a composer is, that I am not able to update the layers (by pressing ...
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27 views

How to add dynamic text in standalone PyQGIS to reflect iteration of layer names

I am working with a standalone PyQGIS script below (that was given as an answer to How to iterate over layers and export them as PNG images with PyQGIS in a standalone script). The script exports the ...
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0answers
33 views

The features don't appear at the first time in my exported PDF

my problem consists of exporting to PDF format. The first time I run my code (Text Editor of QGIS) the PDF only has the legend. But the second time, it has the features. Changing the line of ...
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45 views

Approach to controlling which layers display in a QgsComposerLegend

I've tried 2 approaches to control what shows up in print legends. Neither of them work which is troubling because other than pruning the layerRootTree in advance of composer.addItem(legend), there ...
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2answers
39 views

How to set the paper size to A4 for a PDF export with pyQGIS?

I have been developing this code, based on the official documentation of QGIS and some codes in gis.stackexchange. But my problem is that I don't know where to establish my height and width to make a ...
2
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0answers
22 views

addItem() method doesn't work [closed]

I show you my code, but basically, I have been following the steps in the official bibliography about Map Composition The code works, but I don't get the items I have been adding to the map (scalebar, ...
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0answers
19 views

I can't define “enum QgsComposerItem::ItemPositionMode ” to UpperRight

In order to create a new map layout with labels, I have to set in my code the position of the labels with ItemPositionMode, but it the parameter is not accepted: from qgis.core import * from ...
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0answers
20 views

QGIS cannot load macro function?

This has me stumped. For some reason, I can no longer run a function from a project macro even though macros are enabled (from Settings > Options > General > Enable macros > Always). Just ...
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31 views

How to georeference *.tiff to a given feature geometry automatically?

I´ve got the task to georeference an tiff image to the referencing polygon footprint (Polygon). I have found a lot of ways to do get the footprint from a raster but I could not find a way to use ...
4
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1answer
50 views

Can't delete features from layer using QGIS' Python API

I've only recently started using QGIS and it's Python API. Currently I've loaded two OpenStreetMap datasets. I would like to remove lines with from the second set where the name is already present in ...
2
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1answer
24 views

Create different print composers from different layers added to QGIS

I'm using QGIS 2.8.3 with windows 10. I want to know if it's possible and how to create, using python code, from each layer (in the table of content) a print composer to each one of them. Any ...
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2answers
46 views

How to connect push button in dock widget form?

Following this tutorial as a guide, I created a plugin using the Plugin Builder with the dock widget form. I am now trying to connect a pushButton to a function. The following is a snippet of code: ...
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1answer
35 views

Label only selected features with PAL PyQgis using an expression

I'm trying to label only selected features with an expression using PyQgis and the PAL functions, but I don't find any example and the API don't help me a lot (or I don't found it). My Qgis version is ...
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0answers
12 views

There is a Run Time error wile using the console.in QGIS

I was writing a post where I have pointed in my code which lines of code "make" QGIS to fail. But as the time as I was writing the post, I tested the code again in the Text Editor of QGIS (2.14). ...
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1answer
65 views

Writing result of PyQGIS to shapefile

I try to perform some zonal statistics on a shape- and rasterfile and write the output to a completely new shapefile! import sys # where is the module ...
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2answers
29 views

How to read the saved extent of the QgsProject?

I am trying to access the extent of QgsProject. How can i do that with PyQGIS?
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0answers
55 views

Problem using processing.runandload() [closed]

I'm writing a QGIS plugin using PyQGIS and I have a weird problem. When executing following line of code: processing.runandload("qgis:createpointsalonglines", r"Clipped", 1, 1, 0, r"memory:nodes") ...
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49 views

Issues updating field values programmatically for particular field data type on 64bit Windows computer using QGIS 2.8.7

I have an issue with a plugin for QGIS 2.8 I'm developing when using it on a Windows 64bit machine (as opposed to 32bit). I am trying to update values in a particular field in my plugin, and the ...
1
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1answer
50 views

Why does joining all layers in a group not work?

I am attempting to re-join all layers within a group to another layer ("Main.shp") outside of this group. The idea is for users to change values in one of the group's layers. As these layers are ...
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2answers
57 views

What's the correct syntax to use Processing gdalogr:merge from python?

I am using gdalogr:mergein Python console in order to merge to rasters (.tif) But I don't really understand the first parameter, where I have to put two variables. I get the following error: ...
4
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2answers
50 views

How to get layers in x number of subgroups?

I have a project which has dozens of groups and subgroups. E.g.: Main_Group > Sub_Group_1 > Sub_Group_1A > Layer_1A > Layer_2A How can I access ...
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0answers
30 views

Eclipse PyDev has quit recognizing QGIS objects

I followed the instructions for setting up Eclipse with PyDev to start creating QGIS plug ins found here: http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/ide_debugging.html after doing ...
0
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1answer
18 views

QGIS algorithm parameter: <ParameterString> [duplicate]

I have been working with the algorithm gdalogr:warpreprojectand have failed several times in the parameter in the title. Now, the problem is solved. It was about the EXTRA parameter. I read 3 books, ...
2
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0answers
49 views

Deployment of optical fiber QGIS Python

The subject that I’m working on is the deployment of optical fiber . I have a shapefile which represents a country containing homes. And I have another shapefile representing an infrastructure plan of ...
4
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2answers
174 views

How to render layer into png in a standalone application?

I would like to use standalone appliction to apply .qml style to a layer and use QgsMapRenderer() to save it as image on a hard disk. The are a lot of questions like mine at this site and it seems ...
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1answer
45 views

Error doing processing.runalg

I have been working in this code but I am getting the following error: Traceback (most recent call last): File "", line 1, in File "c:/users/miguel~1/appdata/local/temp/tmpdsyhqn.py", line 17, in ...
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0answers
25 views

How to programatically populate a field_4 after choosing values from other fields

I'm working with QGis 2.8, editing the attribute table of a SHP file, named "myTable". I need to populate field_4 with the conditions listed below: For 1 to n (it runs across records of myTable) ...
2
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1answer
38 views

Module Map Composer not found

I am using Map Composition, but I found in QGIS 2.14 (Essen) Text Editor that when I try to import MapComposerit returns that this module is not found. This is the error : File ...
2
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2answers
53 views

I don't get any output from Reprojection

I have recently posted a Reprojection issue. I found the solution, but now I can't get the output: I load the resulting reprojection by code, but first, I look into the folder where I have indicated ...
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7 views

Override renderDiagram method from QgsHistogramDiagram

I try to reimplement the renderDiagram() method from QgsHistogramDiagram to add some labels directly to the diagram (using the position argument). So far, I tried to set up my own class to override ...
2
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1answer
47 views

Algorithm fails (not found) : gdalogr:warpreproject

I am using the code in "QGIS Python Programming Cookbook", testing the code to learn about programming in QGIS. But when I try to reproject a raster, I get the error: Error: Wrong number of ...
2
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2answers
179 views

How to iterate over layers and export them as PNG images with PyQGIS in a standalone script

I would like to export specific layers as a png from a QGIS .qgs map. From the table of contents the script would first export the "boundary, climits, and Div1_Irrig_1956_0" layers as one png. The ...
2
votes
1answer
48 views

How to automatically reload a layer every 30 seconds?

I need to 'triggerRepaint()' a rasterLayer every 30 seconds, it's possible do it in QGIS? perhaps, a background process ui in python? create a watcher in python like QFileSystemWatcher
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11 views

Can't get new layer from QgsGeometryAnalyzer [duplicate]

I have this user's problem as well. When I click "RUN" in the Text Editor in QGIS, nothing appears, and I haven't got any errors. It is a very symbply class but surprisingly, I can't get any result. ...
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0answers
32 views

ogr2ogr - Shapefile database SQL query; missing .cpg and .xml

I am using gdal and ogr2ogr to perform a SQL query on a database of shapefiles with the code below. The geoprocessing works and the appropriate shapefile is extracted from the query, but when I print ...
2
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1answer
45 views

Displaying layer after using QgsGeometryAnalyser?

I have already discovered this class, but I am confused. If I am doing a analysis on the current layer, I don't know why it is not displaying on the map. lyr =iface.mapCanvas() layer = ...
2
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2answers
47 views

I am looking for a Python method to Split the list of attributes in a layer

I have a list of attributes in QGIS: [137.0, u'0101S', u'MUNICIPIO', u'28004', 19849.4753178, 22000935.5836, u'\Alamo, El'] And I am trying to obtain each element in the list, using pyqgis. I ...
2
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1answer
29 views

using PyQGIS to subsample a region of a raster layer's pixel data

I am having trouble sampling multiple pixels from a raster layer at oe time. If I want to sample pixel data from a layer at a particular coordinate I can write. ident = ...
4
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1answer
35 views

PyQGIS toggle group visibility (and recursively subsub…group visibility)

I would like to set visibility of a layer group and all of its children (and grand-children and so on...) using PyQGIS (QGIS 2.14.1). Assume the groups name is g0 with subgroups g0[1...n] and ...
2
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1answer
41 views

Retreive pixel value from raster layer in pyQGIS

I am trying to access the pixel data in all bands from a raster layer in QGis from the Python Console. I have looked at several online resources including ...
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0answers
18 views

Atlas transparency in Pyqgis

I use atlas with PyQGIS. In my atlas i use a feature (atlas feature) with invert polygon, this feature have the transparency = 50%. When i generate atlas with composer no problem, but if I use the ...
3
votes
1answer
132 views

How to change a project variable using Python?

I'd like to change the value of a user-defined project variable (can be manually edited in Project Settings | Variables) using the Python console. I tracked down the setVariable() function in the ...
0
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1answer
52 views

Plugin with QT Creator and Python [closed]

I would like to develop a selection-plugin in qgis. It doesnt run because there is a Problem with the python script. I can select the layer. However, I dont know how can i choose between "ZD", ...