Python is an open source interpreted programming language used in many GIS programs.

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41 views

I tried to run QGIS using python but I couldn't get any output on screen?

uri ="C:/Users/rajagopalv/Desktop/poi_sunnyvale.csvdelimiter=%s&xField=%s&yField=%s" % ("|", "x", "y") vlayer = QgsVectorLayer(uri, "address_sunny", "delimitedtext") ...
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1answer
73 views

ERROR 000271: Cannot open the input datasets Failed to execute (CompositeBands) (arcpy)

I am trying to stack bands 3 and 4 together for numerous landsat scenes, and I am trying to do it using a loop and arcpy.CompositeBands_management. The code I am using is: import arcpy #set ...
2
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1answer
93 views

How to use spatial filter in PyQGIS?

I have a buffer and need to filter a multipoint layer (QGSVectorLayer) so that I would get only features intersecting the buffer. What I've found: a) setFilterRect() This doesn't accept polygon ...
2
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2answers
113 views

How can I import shapefile in python?

How can I import a shapefile in python? from PyQt4.QtCore import QSettings, QTranslator, qVersion, QCoreApplication from PyQt4.QtGui import QAction, QIcon, QFileDialog # Initialize Qt resources from ...
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2answers
110 views

Critical facility pipe connections in python

I'm trying to find a way to determine pipeline connections located downstream a critical facility and score how far those connections are from the facility. Is there a way to accomplish the above ...
2
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1answer
96 views

How can I create a polygon from points and assign it a color in QGIS using python?

I want to create a new vector layer, containing a polygon from a set of given points, and giving it a color.
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1answer
110 views

QGIS set all layers with custom transparency with python?

I'm exploring QGIS python functions to set all raster layers with a custom transparency, i.e 0,0,0,100 . Looking at some previous questions. There is a way to loop all the layers, but the aspect to ...
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1answer
90 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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126 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 ...
2
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1answer
93 views

How to split name in label so only first two words appear?

The labels for my feature SSA_NAME are approximately 5 words long. I would like to shorten the labels to only 2 words. Every time I try a different code I receive either an error message or my layer ...
2
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1answer
69 views

Error: Algorithm not found (QGIS)

I wrote the following code using QGIS'API. import os from qgis.core import * import qgis.utils prefix_path = os.environ['QGIS_PREFIX_PATH'] QgsApplication.setPrefixPath(prefix_path, True) ...
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1answer
51 views

problem deleting shapefiles because still in use by arcpy cursor [duplicate]

I have a function outputTblContents which contains def outputTblContents ( path ): rows = arcpy.SearchCursor(path, fields="alpha; beta") for row in rows: print("{0} => ...
2
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1answer
218 views

PyQGIS standalone script does not work. Error “QGraphicsScene::addItem: item has already been added to this scene”

I try to test a PyQGIS standalone script which should just show one Shapefile. Sounds pretty simple but does not work. Here is my script: from PyQt4 import * from PyQt4 import * from PyQt4.QtCore ...
2
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1answer
110 views

How to use %i%“.csv” in arcpy to name an output csv file?

I am using arcpy to describe datasets and output the results into a csv file. I am doing this via a script in arctoolbox and would like to save the file in the same folder as the file being analysed. ...
2
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1answer
51 views

Determining the cosine of the angles between two lines using dot product

SCENARIO:I have a certain buffered region (lets say a one way road segment), which will have only one allowed direction represented by vector A. And, there are several other lines which may or may not ...
2
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2answers
155 views

Cutting a polygon out of another polygon with python [duplicate]

Licence: ArcEditor Version: ArcMap 10.0 i have some issues to separat my data with python. To illustrate the problem, i have simplifyed the data with figures. I want to cut the blue polygon ...
2
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1answer
229 views

How to efficiently use a Postgres DB with Python

I have a Postgres DB with a lot of lines that are too long and so now I want to split those lines into smaller ones. This is why I started writing a little python script for that job. Basically it ...
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1answer
88 views

SelectLayerByAttribute and Where Clause

I'm trying to select the minimum value from a field to select and export that one feature to a temp shp so I can copy the field data from the point to a line. So far I have this: import arcpy from ...
2
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1answer
61 views

How to know if two geometric figures are approximately equal?

I would like to know how to determine if two geometric figures (the_geom) are approximately equals. By the way, I'm working with Python, PostgreSQL and Postgis I have the following geometries: ...
2
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1answer
125 views

Change layer datasource in qgis project with python

I have different qgis project with some layer and their datasource like ../my_path/my_file.shp. I need to insert this shp file to a remote db. For do it i use shapefile from PGeo module and it's work ...
2
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1answer
86 views

Unable to execute a python script that was exported from ModelBuilder

I have a model that copies a single F.C form SDE geodatabase to a scratch geodatabase then copies it back with a new name to the same SDE geodatabase again. And this works perfectly form the model. ...
2
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1answer
103 views

Using pyQGIS transform a layer of polygons into a layer of holes inside a bbox

I'm using python in QGIS. I have a layer of polygons (its a result of some earlier dissolving and has no overlapping polygons but some holes and islands in holes etc). I want to build a new layer ...
2
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1answer
78 views

Clip Point Features to Polygons with Model Builder/ArcPy

Here is the context of my question: I have point features for about 2000 individual trees spread throughout 50 different tree districts. The tree districts are polygons in a polygon feature class and ...
2
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1answer
96 views

PyQGIS: subtracting two values and append ID to list

I would like to subtract two values retrieved from qgs feature iterator objects and append the value of the feature id to a list depending on a condition. I have two layers: roadsLayer pathsLayer ...
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1answer
122 views

QGIS Python - raster as point layer, coordinates issues

I would like to create point layer for storing values retrieved from a raster file. My idea was to iterate through all raster cells. If cell value is different than NULL, I wish to create a new point ...
2
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1answer
214 views

Python GDAL: ogr.open or driver.open?

I’ve been using GDAL with python to manipulate shapefiles. When opening a source file I first set the driver to “ESRI Shapefile” before calling the driver’s "Open" method with the required shapefile. ...
2
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2answers
240 views

Is it possible to sort the features by an attribute programmatically?

I have written a PyQGIS script that loops through an attribute table and finds duplicated values in a target attribute field. My technique requires that the attribute table is first sorted by the ...
2
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1answer
84 views

How to find the distance of a point from the begning of a StringLine with shapely?

I have a route (represented by StringLine) and a location (Point) and I need to find the progress of the location in the route. The progress is the distance in meters from the begning of the route. ...
2
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1answer
159 views

QGIS Modeler flexibility and errors?

I'm trying to build a simple multi-step selection (by attribute) with the QGIS Modeler. I created a simple sample layer to avoid data-driven errors. Now I want to query the layer and select features ...
2
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1answer
85 views

Odd behavior in a QGIS plugin: my function is triggered twice

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 ...
2
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1answer
277 views

Why processing.runalg(“gdalogr:rasterize”…) is not creating out files when running in the QGIS 2.6.0 console?

I want to use the QGIS python scripting functions to turn to rasterize a point vector using many different dimensions. Right now my code looks like this: import processing RasterPixelSize = ...
2
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2answers
204 views

How to get cell value along Flow Direction

I have: a flow direction raster where I took off (assigned NoData value) the cells that overlayed the river network (from flow accumulation). a perfectly overlapping raster where I asigned a ...
2
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1answer
185 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 ...
2
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1answer
137 views

Error with Python Script using Shapely

My professor gave us a basic Python script that demonstrated how Shapely works with a shapefile, however it's not working for me. Here is the code: from shapely.geometry import mapping, shape from ...
2
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1answer
136 views

Getting values from Qt widgets and using them for a buffer

I am writing a simple plugin that finds buffer. My gui has 2 combo box and 1 Line edit. The first combo box will have a drop down of values from column 'States' and 2nd combo will have a drop down of ...
2
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1answer
327 views

How to apply a filter to multiple vector layers in QGIS?

I am trying to apply an attribute filter to multiple layers in QGIS at once. The filter is to be applied to .osm data brought in through PostGIS to QGIS. I have tried selecting multiple layers -> ...
2
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1answer
226 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 ...
2
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2answers
212 views

How to make a list of ESRI GRID rasters in Python

Tipically, ESRI GRIDS are not defined by a file extension like for the .tif files, but they are stored in a info folder plus an extra folder corresponding to the name of the raster. Arcpy allows to ...
2
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1answer
161 views

Edit attribute table for shapefiles in folders and subfolders with arcpy?

Continuously to Merge shapefiles in folders and subfolders with arcpy I try to edit attribute table for 20 shapefiles that spread in big a folder and are divided to a lot of sub folders. All ...
2
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1answer
368 views

Load the raster image which is in TIF format using QGIS API

I am quite new inthe field of GIS. I am interested in is to load the raster image which is in TIF format using QGIS API I have followed the steps given the in the follwing link to load shape file ...
2
votes
1answer
106 views

Python library for geometrical calculations using with GRASS GIS?

I have to do some geometrical calculations in 2D(point, lines, line segments and intersection points) in Python, and then use it in GRASS GIS. What is the best library to use for it? I'm trying with ...
2
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2answers
322 views

Call output files in temporary directory through Processing Toolbox (python)

I need to create temporary files as intermediate output to be used with processing algorithms. So, I implemented this: Processing.runalgorithm("grass:v.to.rast.attribute", ........, None) This line ...
2
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1answer
115 views

QGIS Python SQLite using variable

I have been looking for answers and working on this for many hours. In the spatialite database table nodes, id is an integer. idValToNode = 854 sql = 'UPDATE nodes SET obsolete = 0 WHERE id ...
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2answers
106 views

List all feature layers

I will often create many temporary layer files with MakeFeatureLayer_management. I was wondering if there was a means to list the temporary layer files I've created. I've tried setting the workspace ...
2
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1answer
52 views

MakeFeatureLayer_management wrong output

I have a huge database with Sightings from whales and dolphins from 1995 till today. So I want to sort the database with python. Till now I can make FeatureLayers for each year for ...
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3answers
278 views

Executing Python code takes a lot of time (more than 2 hours)? (Arcgis10.1)

I am executing this Python code, in which I am trying to determinate the position of neighbor parcel (north, south, east, west). It works fine but it took 2 hours for just 50 parcels! I think that ...
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1answer
84 views

Qgis how to combine a geotif with a country border shape file?

I have 2 files. A geotif with different values and 1 shape file with country borders of this area. Can I generate with this 2 files an image with the country borders and the data from the geotif? ...
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1answer
88 views

Nested SearchCursor functionality

I am trying to ultimately compare the gate height to the corresponding fence height located nearby. So far I have come up with the following: gates = "gate_line" fence = "fence_line" ...
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1answer
221 views

How to format an excel table using python

I am trying to come up with a way to export an attribute table as a formatted excel table in ArcMap 10.2. I am aware that there is a "table to excel tool" in the conversion toolbox, but I am not sure ...
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2answers
100 views

QGIS - Edit UI - Python Init function localization with QTranslator

I have interaction with layer defined by custom designed UIs. In layer properties the following settings: Edit UI - customline.ui and Python Init function: customline_set.py. #coding: utf8 from ...