Python bindings for QGIS.

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How to create a polygon grid with un-even spacing between research plots?

I have an orthomosaic of a crop field with small research plots (3.8 X 1.44 m and 0.22m b/w plots and 0.50m b/w range spacing). I would like to create a polygon layer using this information. After ...
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2answers
19 views

How to join the attributes table from one input layer to another layer with unique id using python

I have one input layer with the attibute values and i wanted to join the attribute table of the input layer to the another layer with unique values using python. ...
2
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1answer
11 views

Checking for Changes in a WFS

I'm responsible for updating many spatial datasets within my organisation. Some data suppliers notify me of a change, some suppliers don't. Sometimes it's not easily apparent if the data has changed ...
3
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1answer
40 views

Refreshing “layer render order” widget

i made changes in the render order of my map canvas using a : qgis.utils.iface.mapCanvas().setLayerSet(a) "a" being a list of QgsMapCanvasLayer My code is working as expected (i see result on map ...
2
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1answer
149 views

How to print 2 maps in the same PDF page using PyQGIS?

I am trying to generate a one-page PDF document containing the following items: 1) On the left half, a full state map (say, New York State). 2) On the top right quadrant, a map that zooms in to one ...
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1answer
45 views

QStringList() error in plugin of QGIS 2.10

I have made a Dialog in PyQt for use it like a plugin under QGIS 2.10 The Dialog works fine like a standalone application, but if I try to call it like a QGIS plugin, I get this error: ...
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1answer
18 views

Failed to create memory layers in QGIS application on Linux

I have written a python class which reads properties of map layers from an XML file and creates appropriate memory layers. I have developed and tested this code with QGIS 2.8.2 on a Windows 7 machine ...
2
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1answer
25 views

How to dynamically change images in map reports?

I need to make a report about several cadastral parcels which data are contained inside three different tables of a database. Report must contain: Cadastral data taken from the three tables A ...
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2answers
30 views

Where is the QGIS API action for “deselect”?

Where is the QGIS action for the “deselect” toolbutton in the 'Attributes" toolbar? I do not see this action in the QgisInterface class or do not recognize it by name. Is it missing from iface? I'd ...
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0answers
18 views

How to write a test suite for QGIS standalone application

I have a rather simple QGIS standalone Python app (2.8.2, Windows 7/64), with some published methods to create different types of geometric primitives (rectangles, circles). class MyApp(QMainWindow, ...
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1answer
31 views

How to calculate zonal statistics from multi-band raster for each polygon using python?

I want to calculate the zonal statastics from multi band raster for a polygon layer. When I am using this snippet of code: vectorlayer=qgis.utils.iface.mapCanvas().layer(0) rasterfile = ...
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2answers
313 views

How to determine the coordinates of the corners of the raster layer

How can we determine the coordinates of the corners of the raster layer? The image opens function QgsRasterLayer.
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1answer
61 views

How to avoid a QGIS crash when it is appended a symbol layer in a symbol?

When I run the next code at the Python Console of QGIS with a line vector layer: symbol1 = QgsLineSymbolV2.createSimple({'penstyle':'solid', 'color':'black', ...
2
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1answer
52 views

Processing algorithm fails from Python script

I'm trying to write a Python script performing a geoalgorithm. What is surprising me is the following: I first test the algorithm by QGIS (2.8) interface. In my case, the GRASS interpolator ...
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0answers
17 views

PyQGIS Use of predefined color ramps

I´m trying to apply one of predefined color ramps to a categorized field in a vector layer. To do this, I'm using the code below suggested by Irssvt in another post. However, I cant´t see the result ...
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1answer
24 views

Styles not applied when using QgsMapRenderer

Using pyqgis, i am trying to export some maps as images using QgsMapRenderer. Here is the layer/style setup, both load correctly: lyr = QgsVectorLayer(uri.uri(), 'Report', 'postgres') styleload = ...
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2answers
142 views

How to read Oracle data with PyQGIS? (“identifier is not long” error)

Do you have any idea how load Oracle spatial data to QGIS with using the PyQGIS? Is it possible? I try: uri = QgsDataSourceURI() uri.setConnection("*host*", "1521", "*database*", "*username*", ...
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0answers
56 views

How to wait for mapCanvas render before taking a screenshot?

i am trying to iterate over a large list of features and making a screenshot of the selected feature. My problem is that it seems to be a delay between the refreshing of the canvas and the taking of ...
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23 views

How to react to network events

I am in the process of writing a Plugin which should react to some data (XML-Format) sent via a socket connection. Since I have never worked with IPC in terms of python before and my knowledge of IPC ...
1
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1answer
39 views

How to get the coordinates inside the polygon using python

I have a polygon and using this code snippet we can get the coordinates boundary of the polygon. canvas = qgis.utils.iface.mapCanvas() aLayer = canvas.currentLayer() coord = ...
2
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1answer
24 views

Show VectorLayer in window

I'm new in PyQgis. I can create vector layer and lines/polygons on it : layer = QgsVectorLayer("LineString", "points", "memory") pr = layer.dataProvider() pt = QgsFeature() point1 = QgsPoint(0,0) ...
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2answers
244 views

Is there a function to select a region of a map for further processing with Python?

I would like to select a map's region in QGIS for further processing with python console. Ideally I would like to select the region with a mouse drag (like Gimp crop function) and then e.g. analyze ...
3
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1answer
39 views

Moving cursor using PyQGIS?

I would like to move the cursor to a given x,y coordinates of the MapCanvas. Is there an easy way to do this using PyQGIS?
3
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1answer
1k views

legend groups and layer position/order qgis 1.8

I'm tring to programmatically create layer sequence also using groups. Simple python code: layer = QgsVectorLayer("004cp000.shp", "004cp000", "ogr") QgsMapLayerRegistry.instance().addMapLayer(layer) ...
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1answer
224 views

Adding new menu item to QGIS Desktop app

I need to add new menu item to the top level menu of QGIS Desktop (2.7.0); I.e. it shall be on same level as "Project", "Edit", "View", "Layer" etc. As far as I know there is pretty nice way how hide ...
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1answer
151 views

How to enable the snapping options for vector layer using the python programming?

I want to enable the snapping options for the the existing layers using python programming. How can I do this?
2
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1answer
37 views

The QGIS atlas defined with pyqgis and a QPT template exports the same maps

I need to generate an atlas for each feature from a layer for reporting. There will be created a few maps. The centre of each map must be focused on each feature. In this task I use a predefined QPT ...
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1answer
64 views

Accessing layer's visibility presets?

is there a way to programmatically access the layer's visibility presets defined in the layer tree view widget ? (methods, properties ... ?) Thanks ! To avoid misunderstandings the part i want to ...
2
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1answer
36 views

QGIS crashing/failing when dissolving multiple shapefiles in a Python loop

I am using QGIS 2.10 (but I've also tried 2.8) to loop through all the shapefiles in a folder (those ending in .shp) and perform a dissolve function on each of them. However, when I run the following ...
6
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1answer
2k views

How can I add button to the QGIS toolbar or create my own toolbar?

I want to create a button and add it to the QGIS toolbar or alternatively create my own toolbar and add the button here. A plugin should be started when the user clicks the button.
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0answers
39 views

How to define a custom function that returns value of a field in an unsaved form

Filter expression builder in QGIS 2.8 allows us to define custom functions using python. I'm intrested would it be possible to define a function which returns a value of a field in an unsaved form ...
1
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1answer
26 views

Python ogr filter attribute SQL

I have a shapefile with 4 attribute fields (MC_ID, MC_info, C_ID, C_info). I want to change some MC_ID values selecting the features by C_info. For example: I want to set MC_ID = 2 for C_info = g19, ...
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1answer
28 views

Valid shapely dumps WKT becomes None when used as input to QgsGeometry

I'm trying to produce a multipolygon feature in QGIS. I am producing filled contours with Matplotlib, taking the multipolygons representing each contour level, using shapely to produce WKT, and then ...
2
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1answer
344 views

Display plugin icon [closed]

I'm unable to setup the display of the toolbar icon for a plugin in QGIS 2.0. I have compiled the "resources.qrc" with the correct path and filename, and checked possible spelling errors in the code. ...
2
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1answer
200 views

Accessing CRS info with pyqgis in a standalone application

I'm currently having trouble accessing and defining CRS information in a standalone application. I've read the API documentation and have tried it in the python console in QGIS 2.2.0. The python ...
2
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0answers
38 views

How to change the symbology of selected features in QGIS

In QGIS selected features are normally highlighted in a different color to draw user’s attention on the selection. The default color can be changed programmatically. As a nice to have my standalone ...
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2answers
158 views

How to replace VectorWriter with QgsVectorFileWriter?

Within QGIS 2.8.1 I found within the Processing Toolbox a script called "Points on crossing lines" which should exactly as it is named. Unfortunately it needs processing.core.VectorWriter which I ...
4
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2answers
201 views

What's the most efficient way to load feature attributes into a numpy array?

I am currently working on an add-on that relies on the user choosing fields of tables (that can be from shapefiles, csv or dbf) that are open in QGIS and then making computations with such data. ...
2
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1answer
47 views

Why does the QgsFeatureIterator crash in my stand alone script?

I'm trying to write a standalone script in qgis 2.10 in ubuntu I have written a script which crashes when I run from bash but works fine from inside the qgis desktop environment. The script is: ...
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2answers
29 views

Importing fmeobjects into PyQGIS

I use FME a lot for manipulation of spatial data, and would like to leverage it's Python library, fmeobjects in PyQgis. If I run the following in my standard Python IDE it works fine: import sys ...
2
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1answer
63 views

QGIS Plugins & Tools that replicate Select ArcPy Tools

I developed a complex python application for road generation from GPS Devices that uses a few Arcpy Tools. I want to try and replicate this Applications functionality using a freeware like PyQGIS ...
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2answers
55 views

QgisInterface.addVectorLayer Error

I am Esri-trained, trying to move into QGIS using Python. Simply trying to add a vector layer in Qgis returns the below error: TypeError: QgisInterface.addVectorLayer(QString, QString, QString): ...
1
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1answer
56 views

Finding and deleting duplicate records in attribute table in QGIS

I have around 1 Lakh+ (100,000+) point features in my shapefile, which has some duplicate records in it. I had found the duplicate records present in the attribute table and print those in python ...
2
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1answer
56 views

different way to build qgis python standalone application

There seems to be 2 different ways to start a Python QGIS standalone script. The official tutorial is using : from qgis.core import * # supply path to where is your qgis installed ...
3
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2answers
368 views

Can I Dynamically Update Symbol Ranges?

Background: I'm currently trying to dynamically change the ranges for a layer with new style graduated symbology. Problem: I thought it may be as simple as updating the ranges for the existing ...
2
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1answer
199 views

Import error when utilizing QGIS's Python Init function

Based on the answer to Referencing Qt UIs external to plugin with python. I'm trying to utilize the "Layer Properties / Fields / Python Init function" to execute a file (test_file.py) that is located ...
0
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1answer
44 views

How can we export shapfile to svg format using Pyqgis

I am doing a project where i have to export file from shapefile to svg format using Pyqgis. i have read some articles regarding simplesvg plugin but i don't know how can we achieve the same task using ...
4
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1answer
73 views

QGIS Export Shapefile

i am trying to export selected feature using pyqgis. till now i have tried these codes. after using this i can select feature but dont know how to export selected feature to new shapefile. canvas= ...
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1answer
34 views

How to restrict panning in QGIS to a given extent

I'm going to build a QGIS standalone application. According to the requirements full extent equals to the extent of a predefined rectangle (say bounding box of a parcel). The application should start ...
9
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1answer
1k views

Is it possible to show our custom message in QGIS Status bar using python?

Is there any way to show our custom message in Qgis Status bar using python? Just like in arcgis "IApplication.statusbar.message(0) = "Please wait..." like that is there any option to show ...