Python bindings for QGIS.

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Creating Convex hull and finding buffer in QGIS

I have a layer and features are selected using Select Features by freehand tool and for that selected features, convex hull was done and for that convex hull i am trying to find buffer and write it in ...
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1answer
19 views

Buffer for features selected in the mapcanvas and writing to csv file

I have some features selected by using "Select Features by Freehand" tool in QGIS and try to find the buffer for those selected features alone and write the city and state names within in the buffer ...
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5 views

Use raster memory layer from QGIS processing result

I want to apply subsequent QGIS raster processing algorithms in a python script. I want to use memory layers for intermediate calculation results since I am only interested in the end result. As ...
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1answer
7 views

PyQGIS select layer by name, odd behavior in a plugin

I have a plugin with a function (triggered by a button) that selects a specific layer by name, then shows its attribute table. When I close the plugin and open it again, the attribute table pops up ...
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1answer
16 views

How to select from selection with PyQGIS?

The expression box has a handy "select from selection" button. Is there a way to emulate this with python? I have the basic expressions down, but can't find a way to do this.
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1answer
19 views

How to do a buffer operation for a polygon drawn by the user using python in QGIS

I have a polygon drawn on the map canvas.Say the polygon would be drawn by using "Measure Area" tool in qgis.Now, I want to do buffer for certain distance around that polygon.I can see the below ...
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3answers
2k views

How can I fix “ImportError: No module named qgis.core”?

First of all, I'm using Python 2.7.3, QGIS 1.8 (Lisboa) on Windows 7 pro 64 bits. Now let's go to the actual question: I have written some code (Python) that works well within the QGIS built in ...
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1answer
34 views

PyQGIS load dxf file as a vector layer

Can somebody help me with loading a dxf file as a vector layer with PyQGIS? Is QgsDataSourceURI an option? I've tried it with this code, but it didn't work. fitxer="/tmp/prova.dxf" uri = ...
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2answers
1k views

QGis 2.0.1 mapserver extension missing

I tried to export my Qgis projects to mapserver, using RT mapserver extension, because there is not any other extension in my version of QGis.(QGis 2.0.1 Dufour on ubuntu 12.04 LTS). After installing ...
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1answer
175 views

How can I add grid lines to a print composition using pyqgis?

I'm writing a qgis plugin to create an image in the print composer of the current map. I can get the map rendered in the proper place with a frame of the right width, and I can get grid annotations ...
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1answer
20 views

Warning message needed when there is no specific layer instead of python error

In my plugin, when I click a button it will call the findTheCityNames function which is attached below and get features if there is a particular layer. What I want is if there is no specific layer in ...
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1answer
42 views

How to get a layer by name in PyQGIS?

I have a plugin which finds buffer for list of cities, provided the distance. The state and city names are taken from the attribute table and gets filtered accordingly. What I want is My plugin should ...
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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
27 views

Global name canvas is not defined

I am just trying to print the layer name using python in my QGIS plugin by following code. allLayers = canvas.layers() for i in allLayers: print i.name() It is saying an error: Global name canvas ...
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28 views

Error in clicking browse button in my plugin [on hold]

I have a browse button in my UI in my plugin and when in click it, it throws an error which is attached. Also code is attached for reference. def __init__(self, iface): """Constructor. ...
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1answer
402 views

QGis Zonal Statistics Plugin NoData included in Calculations

I have been trying to use the QGIS zonal statistics plugin. My raster has a nodata value of -99999 and all other values are positive. After computing the mean zonal statistics there are a number of ...
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2answers
578 views

Load and display a layer from SQL Server using PyQGIS

I'm having a go at using pyqgis from within the QGIS python console to load a layer from SQL Server and display it. I feel like I'm part way there but I'm having a real issue getting the layer to ...
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17 views

Vector Layer Symbology Export?

When programmatically creating / saving a QgsVectorLayer - implementation of the ExportSymbology functionality does not seem to exhibit the implied effects. Does such a command not indicate that the ...
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1answer
29 views

Cannot rename output file using standalone script for QGIS

I would like to rename all output files after my script has finished processing them by adding "(A)" after their file name (eg. Layer.shp -> Layer (A).shp). I received an answer from this post on the ...
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25 views

How to select the buffer region in map canvas in my plugin using python

I am developing a plugin which finds buffer by getting state name, city name and distance given by the user. The plugin works fine and writes the cities that matches the distance in a CSV file. What i ...
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1answer
36 views

How to add label to QgsVectorLayer by Python

my goal is to define label programmaticly for the case similar for the figure below: But didn't find any guidance how to do so using Python. I have a feeling it could be done using QgsLabel but ...
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2answers
1k views

Setting the extent for a QGIS map using python

I am writing a stand-alone application in Python/QGIS that simply creates maps. I want to load vector/raster layers, set symbology, set extent At the moment, that is all! Currently I am just using ...
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1answer
45 views

Download file from network using PyQGIS 2.x

I have a python plugin targeting QGIS 1.8 that uses QgsNetworkAccessManager and QNetworkRequest to issue a GetCapabilities request to WMS servers. With 1.8 everything was working fine. Now we are ...
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1answer
19 views

Error while trying to replace a opened csv file with the newone in my plugin

My plugin does some basic geoprocessing functionalities and write the output as csv file. What i want is when i open some already writed output csv file in a writable mode and try to replace the same ...
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2answers
43 views

How to define layer's CRS and avoid the CRS dialog in PyQGIS?

There is an existing Shapefile, which I want to add. At the moment my code looks like: self.iface.addVectorLayer(self.shpFilePath, "Track", "ogr") It works fine, but i want to define the crs ...
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1answer
42 views

How to add multiple attributes to a newly created feature with PyQGIS

I am creating a form for updating the attribute values of the newly created feature. But when i am updating the values only one attribute field is getting updated. So if i want to update the multiple ...
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1answer
60 views

How to export only certain column from selected feature to csv file in QGIS using python code

I have selected features in QGIS, I want to export only two columns from the selected features to a csv file automatically using python code. I have tried the following code: layer = ...
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1answer
32 views

Does mapCanvas().refresh() not work in QGIS 2.6?

Before I used the function qgis.utils.iface.mapCanvas().refresh() to reload the map canvas after for example a layer color was changed from a plugin. But this is not working with QGIS 2.6 for me. ...
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22 views

Error in finding buffer

I am trying to find a buffer for city provided a state, distance and filepath to write as csv. What i am facing is that the name which i selected in the city combo box alone gets writed in the csv ...
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1answer
26 views

Removing the duplicate values in QCombo Box

In my plugin, there is a combo box which lists city names for a particular state. FOr example, if i chose a particular state and city will be some 20 names in the dropdown. But the first name alone ...
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2answers
156 views

How to set the color of a feature depending on attributes with PyQGIS?

I'm trying to set the color of a vectorlayer feature depending on the feature attributes with PyQGIS. How do you acces the attributes of a vectorlayer feature?
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1answer
39 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
49 views

Layer properties dialog in my QGIS plugin

I am developing a plugin which should display some information like geometry of the layer, feature count etc. Now those are currently displayed in QMessageBox.information. I want it to be displayed ...
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1answer
36 views

Issues with PyQGIS while running a QgsZonalStatistics script

I have experienced a very bizarre issue with my PyQgis code. I simply want to load a raster and a vector layer to do zonal statistics, the first part works perfectly but for the zonal statistic I have ...
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1answer
43 views

How to trigger a QGIS action when a plugin button is clicked?

I tried calling the select free hand tool by below snippet of code. iface.actionSelectFreehand().trigger() I dnt have any idea how to call this when i am pressing a button in GUI. my gui is ...
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1answer
115 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 ...
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23 views

How to change the attribute values of the feature using the custom feature form

When i am using the following command it opens the feature form with all the fields: qgis.utils.iface.openFeatureForm(qgis.utils.iface.activeLayer(), f) But i want to open a feature form with the ...
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3answers
97 views

How to efficiently access the features returned by QgsSpatialIndex?

The PyQGIS Cookbook explains how to set up the spatial index but it only explains half of its usage: create spatial index — the following code creates an empty index index = QgsSpatialIndex() ...
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1answer
38 views

How to compute buffers for certain features?

I used the following snippet of codes for finding buffer. def buffer(self): layer = self.iface.activeLayer() distance = float( self.dlg.DistancelineEdit.text() ) city = ...
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1answer
27 views

How to enable the snapping for a layer with the tolerance value with python programming

I have a vector polygon and vector polyline layer. I want to enable the snapping for both the layer with tolerance value? How can i do that using python programming. I have tried this code but getting ...
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1answer
26 views

How to connect mouseclick to map canvas in QGIS?

How to connect mouse click to map canvas in QGIS using python script? I have two lines of code to connect mouse click to map canvas: button.clicked.connect(self.onClicked) ...
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1answer
67 views

How to import fromUtf8 in QGIS?

# Declare instance attributes self.actions = [] self.menu = self.tr(u'&City_searcher_plugin') # TODO: We are going to let the user set this up in a future iteration self.toolbar = ...
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1answer
38 views

convert vector (point shape) to raster (tif) using python gdal lib in qgis

I'm trying to convert a vectorlayer (point- shapefile) to a raster-dataset (tiff) using python gdal-library in qgis. On Graphical UserInterface I simple choose the menue ...
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0answers
25 views

Error in my buffer plugin

In my buffer plugin, i tried the following code # Get buffer distance and selected city dist = float( myLineEdit.text() ) city = myComboBo.currentText() # Get the feature corresponding to the ...
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1answer
44 views

How to call default tool in QGIS inside plugin using python script?

I want to create a plugin which can draw irregular polygons in QGIS. For that, I want to call the Select features by freehand default tool inside my plugin. How can I do this within a python script?
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18 views

Reading long lat values from line feature

I have created a vector layer selecting starting point and end point of the line and created the line by line geometry in QGIS. How do i read the all long. lat. values in the line feature? v_layer = ...
2
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1answer
54 views

How to save the Map Canvas as PNG with transparent background programmatically?

I wrote a script to create a big number of heatmaps for a given scenario. I would like to save the result of every heatmap as a png image. I have figuered it out doing it with simple Map Rendering but ...
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2answers
145 views

How to delete empty fields from a Shapefile with QGIS or ogr2ogr?

I have a Shapefile with a lot of empty columns but many of them are empty. Using QGIS or ogr2ogr, how do I remove all attribute columns where everything is NULL?
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1answer
43 views

How to exclude a certain attribute from being added to the Processing script output layer?

I have a working script to split a layer by field attributes and save the single features as files: ##[User scripts]=group ##input=vector ##class_field=field input ##output=output file from ...
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22 views

QGIS 2.6 SAGA Processing Algorithm, “Add grid values to shapes”, produces NULL Values

I'm using QGIS 2.6 Brighton on Windows with SAGA 2.0.8 installed using OSGeo4W. I have the same versions installed on OSX as well which is not having this problem. On Windows, I'm trying to extract ...