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

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1answer
493 views

Error: Algorithm not found

I wrote the following code to start using QGIS APIs. in a very short script seen below, the "Error: Algorithm not found" is thrown and "print processing.alglist()" is showing none. Any idea why this ...
2
votes
1answer
159 views

How to open most recent directory using PyQGIS?

For example, when I add a vector layer, next time that I want to add another layer it opens up where I chose my last layer from. How would one implement this in Python and/or PyQgis? I'm writing a ...
2
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1answer
1k views

How to compare string fields in the same table with ArcGIS 10

I don't know exactly if there is a tool for this or a maybe a python script could be more suitable. I want to compare string elements from a field (POI_NAME) with another string element in another ...
2
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2answers
404 views

PyQGIS: How to send signal if layer is currently in edit mode

I'm looking for a way to send a signal if a layer is in editing mode. I tried editingStarted(), but it wasn't working. I'd like to do something along the lines of the what I have below, but can't find ...
2
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2answers
132 views

ArcGIS - Extract by Attibutes in Model Builder

I have a model which at one point uses the Extract by Attributes tool to produce a new raster with just the areas containing the maximum values of the first. I would think that the SQL expression ...
2
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1answer
1k views

gdal polygonize in python error, blank polygon created

I am having trouble using the Polygonize function in python. The cookbook example for this can be found here. The relevant portion of my code is: sourceRaster = gdal.Open('myraster.tif') band = ...
2
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1answer
403 views

PyScripter crashes at “import processing”

I set up PyScripter latest version, 2.7) to work with QGIS (2.2, OSGeo4W install) following http://chelahmy.blogspot.ca/2011/02/setting-up-pyscripter-for-quantum-gis.html. It generally works well. I'm ...
2
votes
1answer
412 views

Mac OS X 10.6.8 QGIS not using user-installed Python 2.7

My QGIS does not recognize the recently installed python 2.7 on my mac osx 10.6.8. it still uses the python version 2.6 that is automatically installed by apple. Opening qgis I always receive an ...
2
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2answers
364 views

raster standard deviation stretch python script

I am looking for ways of applying a permanent standard deviation stretch to rasters via python script. Are there any arcpy raster stretch functions? I was looking for a reference but could not find ...
2
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1answer
133 views

How to Export multiple selected features to PDFs with Python?

I have 77 polygons that mark areas of a satellite image that I want to export as separate PDFs. Each of the PDFs should contain just the polygon (and as much as the surroundings to fill out the data ...
2
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1answer
505 views

Why does OGR driver.Open() for File Geodatabase give AttributeError: NoneType object has no attribute Open?

There are a number of existing Questions that hint at a possible Answer to this Question, but none seem to be providing me with the solution to my problem: How to access feature classes in file ...
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2answers
508 views

Python Def Query Help for multiple layers

I have Three layers in a .mxd, all three layers have a common value I can use, but a different Label in each Layer. As an example, the Value I want to use is "100" In Layer A, the Value is in [Name] ...
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1answer
600 views

Automatic calculation in one attribute table based on values in another attribute table using python

I am trying to fill the fields of one gdb table based on some statistics over the attributes of another shape file. As it was not possible in ARCgis directly, I am trying to use python coe for this ...
2
votes
1answer
147 views

Populate an attribute table field using the 'startswith function

I am hoping that someone may be able to help me. I am new to ArcGIS, and even newer to Python. Working in ArcGIS 10.1, I have done is created a new text field in an attribute table, which I have ...
2
votes
1answer
787 views

GDAL polygonize only certain raster values

I want to polygonize a raster file with GDAL. I only want to rasterize cells with a value of 0. Is it possible to specify that within the polygonize function or do I have to modify my raster before ...
2
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1answer
147 views

Why is arcpy.mapping.ExportToPDF losing layer symbology?

When exporting a map it does not export the symbology within the data frame. I am using the code snippet below. >>> myMap = arcpy.mapping.MapDocument("C:/USERS/NISUSER/DESKTOP/mxd_map.mxd") ...
2
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1answer
86 views

How to run shapefile.py

I'm script challenged and trying to repair a shapefile with a missing .shx. This tool sounds ideal: https://code.google.com/p/pyshp/, but the four step instructions are not enough. Can someone give me ...
2
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1answer
471 views

Python code intended to merge files in subdirectories… not producing merged result

The short python code below is intended to merge a series of files (GIS files) which are contained in a series of subfolders. import arcpy import sys import os PointsMerged = r"C:\GIS\...
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3answers
6k views

No ogr module despite having gdal installed?

I am trying to use the mapping component of the wonderful PySAL package, but for some reason I do not have the ogr module. I was under the impression that it came packaged with gdal. Am I missing ...
2
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1answer
421 views

OGR: How to best use GetFeature on a selection?

I think the following is very confusing sel_str = "ND_14 = '108'" l.SetAttributeFilter(sel_str) l.GetFeatureCount() >>> 1 In a for-loop this gives me for f in l: g = f.GetGeometryRef()...
2
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1answer
458 views

Programmitcally Change Text Font for all Labels on MXD

I'd like to know if there is a way to change the text font for all layers and all label classes within a layer on a MXD. I use a font not often found on all computers for created maps. I love the ...
2
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2answers
296 views

Determine ArcCatalog's currrently selected folder using Python

Is there a way to get the current directory opened in ArcCatalog 10.0 using Python? Something like os.getcwd() but instead gives the selected folder on the catalog tree. Cheers
2
votes
1answer
1k views

Tool to convert Mike Urban network (shapefiles) to EPAnet network

This might be a too localized question, but I hope I'm not the only one here doing pipe network analyses in Mike Urban. I have a model in Mike Urban, and the client wants it in EPAnet format (since ...
2
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2answers
673 views

How can I perform an inside clip on a raster file based on another raster file?

I have a raster file that I would like to use to perform an inside clip on another raster file. I have tried using the extract by rectangle tool, but it gives me values ranging from 3.40282e+038 to -3....
2
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1answer
437 views

Need a Python field calculation that works like the DatePart( ) VB Function

I have a field called Abandoned Year (short integer data type) that I am trying to populate with a four digit year from a column called Decommission Date (Date data type). I have done this in the ...
2
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2answers
77 views

How to travers fields of records without introducing them all in the function?

In my previous question I wanted to reach a field in the field calculation; however, it was pretty easy to introduce a few more inputs for that function. Now, I am facing a problem which needs around ...
2
votes
1answer
357 views

How to store attributes of a large shapefile in a list?

I am trying to store the attributes of a shapefile into a list. With following code it works for smaller shapes: addA = [] While provider.nextFeature(feat): attrs = feat.attributeMap() for (k,...
2
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1answer
609 views

Generate unique ID upon creating a feature?

Looking for a way to generate a unique Global ID within a feature set when a new feature is created. For example, every time a sewer manhole is added, we need to generate a new unique Global ID that ...
2
votes
1answer
1k views

How to get point x and y geometry from a shapefile?

I have a shapefile of US Cities and I want to get the X and Y coordinate of EACH city in that shapefile. I've tried this: for city in city_cursor: geom = city.Shape point = geom.getPart() ...
2
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2answers
2k views

How to calculate volume from a raster file?

I have a raster file containing the depth of water. I need to find the volume of water using that raster file. I need to find the area of each cell and multiply with the depth. How can I do it in ...
2
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2answers
2k views

How to Add Shapefile with Symbology from Layer File to ArcMap MXD using ArcPy/Python?

Say I have a Shapefile: C:\DATA\points.shp A layer file: C:\SYMBOLOGY\symbology.lyr And a map document: C:\MAPS\map.mxd How can I add points.shp to map.mxd with the properties of symbology.lyr ...
2
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2answers
420 views

How can I set the settings of an Address Locator within a Model or arcpy?

I am creating a model that processes a large road dataset, then creates an address locator from the roads. The Create Address Locator tool does not allow me to set options like Spelling Sensitivity or ...
2
votes
3answers
671 views

How to test if geometry is inside another?

I need to tell whether geometries from a shapefile are inside other geometries or not. For example, I want to test if there are trees (represented as points in trees.shp) inside the urban areas (...
2
votes
1answer
950 views

How to “Merge Selected Features” with python?

I have been looking for the answer to this question for some time now, but can't seem to find it! My problem is straight forward: I have one layer It contains lots of features (only polygons), say ...
2
votes
2answers
746 views

upload table to ArcGIS Server

We are building a process which will allow users to submit a table of GPS data to update our central repository for all GPS data. Let's say that the target is simply a SQL data table. At first I ...
2
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2answers
809 views

Error 999998 in Arcpy 10.1

I found an RuntimeError: ERROR 999998: Unexpected Error when lunching Arcpy in my ArcGis 10.1 such as this: Runtime error Traceback (most recent call last): File "", line 50, in File "c:\...
2
votes
1answer
554 views

Compare two Digital Elevation Model (DEM)

I would like to know what's the best method(s) to compare two DEMs without using any GUI soft like QGIS or ArcGIS. I'd like to do it in Python or C++, with GDAL or other similar lib. Does calculating ...
2
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1answer
2k views

Incorrect field name resulted in RuntimeError: ERROR 999999 (Also, better code for adding and calculating fields)

This is the bottom half of my code (and it's been edited somewhat to share publicly). The code works perfectly fine when the fieldList has only three fields in it, but when I populate it with all 108 ...
2
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2answers
1k views

get value from attribute table and change symbology with QGIS and Python

I'm newbie developing plugins for QGIS using Python, this is the first one and it is very frustrating hehe. Ok, this is the situation, I have a 1 point layer in QGIS. Its attribute table has 4 fields ...
2
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2answers
1k views

Where exactly are qgis.gui and qgis.core located?

I'm trying to create a standalone qgis app using pyqgis, i'll be deploying it by copying the install folder of qgis and source folder of my app, and so for the testing purposes i copied qgis install ...
2
votes
1answer
1k views

Python - read shapefile .dbf for encoding

I've written a python script that formats a .shp such that its fields structure matches my office's database view in order to ingest the data of said shapefile. This original shapefile was encoded ...
2
votes
1answer
2k views

QGIS Python version

I have brewed python 2.7.3 onto my Mac (Lion), and installed shapely via pip install shapely. The Polygonizer plugin, however, does not find the shapely library. I see when QGIS loads a Python console,...
2
votes
1answer
689 views

How to use ArcPy cursor to define each feature sequentially as current selection of layer?

I want to implement a script that runs through each feature of a feature class, zooms to the extent of the feature, sets the scale to 1:5.000 and adjacent takes a picture of the scene. The steps are ...
2
votes
1answer
629 views

Setting parameters in Arcmap for dynamic python script

I have a simple python script that works when run from PythonWin, but when I try to make it dynamic to run inside ArcMap I keep receiving: : ERROR 999999: Error executing function. Failed to execute (...
2
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1answer
1k views

Raster operation with grass.mapcalc

I need to iteratively add each raster map of viewshed analysis obtained from a series of single observer locations. For this i used grass.mapcalc with Python (GRASS 7 for Windows). However, my ...
2
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1answer
786 views

Integrated viewshed analysis

I need to do integrated viewshed analysis of a target with several observer locations. I am going to use r.viewshed analysis function in GRASS. With this function, it is possible to perform analysis ...
2
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2answers
2k views

How to incorporate drop-down list within cells of shapefile attribute table using ArcGIS Desktop?

A question has been brought to my attention. When working with a shapefile within either 10 or 10.1. Is it possible to create a python script or some sort of programming language to accomplish this ...
2
votes
1answer
639 views

arcpy.AddMessage and codepage problems

Some times in my tools I need to output Cyrillic text via arcpy.AddMessage function. Previously in 10.0 it was very easy. I had .py file of the tool saved in UTF8 codepage. This code wrote messages ...
2
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1answer
2k views

rtree python polygon index

Sorry for a very basic questions about rtree. I would like to check whether the point is inside the polygon and the distance (point to the nearest point in polygon) as well. I was thinking about ...
2
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2answers
2k views

How do you create a button in ArcGIS and have it run code?

I'm brand new to ArcGIS and have only a year or two of programming experience. I know Java and a little C#. I have a Java app that processes geographical data. I need to have a button in ArcMap that, ...