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

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Exporting arcgis features with attachments, for outside ArcGIS

Arcgis 10 features the new ability to add attachments to individual features to feature classes stored in a geodatabase. One use of this would be to add multiple pictures to a specific location, fire ...
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How could I rate roads for scenic drives?

relative GIS newbie here. I've been working on a personal project to rate roads on how nice a ride they'd be on a motorcycle. I wrote a Python program to work through road data in the TIGER dataset ...
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1answer
756 views

automating roof orientation detection from satellite imagery

A while ago I did a neighbourhood roof orientation survey for solar panel deployment, by visually checking each roof and marking individually whether they were south or almost south-facing. As this ...
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Recommended programming language for remote sensing?

I am beginning studies that hopefully will lead to a long career as a remote sensing specialist. I am currently working with ArcGIS for some applications and learning ENVI for others. I have ...
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How to get raster image as array in Python with ArcGIS

When starting to work with Python and ArcGIS 9.3, I assumed there would be a simple way to get a raster image into a Python array so that I can manipulate it before storing it back as another raster ...
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2answers
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Converting projected geoTiff to WGS84 with GDAL and Python

Apologies if the following question is somewhat stupid, but I am only VERY new to this whole GIS thing. I am trying to convert some projected geoTiff images to WGS84 using gdal in python. I have ...
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How to read an Excel sheet in ArcPy script

I'm writing a python code to convert X,Y points in excel to shapefile. In this process i have toread xy points from shhet1. What is the step i have to include in my process to read data from sheet1 of ...
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Why is this simple arcpy script so painfully slow?

I have a simple arcpy script to update a field in a point shapefile with info from the polygon feature that it is within. It takes 9 minutes to do 100 points in arcpy but a spatial join in arcmap is ...
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Creating line of varying distance from origin point using Python in ArcGIS Desktop?

I'm trying to create a line feature from a single point, using a set distance and angle. Using ArcGIS and Python (I hope). I have a point at these coordinates: X = 400460.99, Y = 135836.76 From ...
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How do I iterate through every cell in a continuous raster?

See this link for more details. The Problem: I want to loop through a continuous raster (one that has no attribute table), cell by cell, and get the value of the cell. I want to take those values ...
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636 views

How to download and process raster files in Python?

I am fairly new to python and seek guidance for a question which might sound trivial to many. Is there a way to use 'wget' in a python script to download raster files from a server and process them ...
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Point (of a linestring) within Polygon using ogr and Python

I'm currently working on a project in which I need to build a topological network out of the geometry features I find in shapefiles. So far using Ben Reilly's open source project I've managed to ...
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How can I iterate over map layers in QGIS python

I'm having trouble figuring out how to iterate over map layers. I can access the currently highlighted layer in the table of contents via iface.activeLayer() but I want my code to operate on all ...
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5answers
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Determine min and max values in an ASCII raster dataset using Python

I have a raster dataset in ASCII format. Using Python, I need to determine the min and max values inside the dataset. I've been told that the header information is key, which contains things like ...
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2answers
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How to compute a new attribute based on changes in another attribute?

I am attempting to classify a set of gps time-encoded point data into behaviors based on different attributes. I have created an attribute that is 0 for home and 1 for away based on location, and now ...
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How do you delete an in-memory Table View?

In a Python script, I'm cycling through thousands of Excel files and using arcpy.MakeTableView to create in memory table views from the first spreadhseet in each file. How do you delete the reference ...
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How can I parallelise embarrassingly parallel GIS operations in QGIS python?

A common requirement in GIS is to apply a processing tool to a number of files or apply a process for a number of features in one file to another file. Much of these operations are embarrassingly ...
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1answer
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How to do a separate Python installation with ArcGIS?

I see a lot of threads asking how you can have a separate Python installation (e.g. the Anaconda or Python XY distribution) and get it to work with arcpy, while not 'breaking' ArcGIS at the same time. ...
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275 views

Count raster value in a bounding box (spatial extent)

I have simple question: given a bounding box, how can I count the number of specific values (say, I am interested in the number of value == 1 ) in a raster in 1) arcpy, or 2) raster package in R?
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Copying file geodatabase on ftp site to local disk using Python?

There is a file geodatabase sitting on an ftp site that I would like to download with a Python script. Right now I'm thinking one way to do this is to copy the ftp geodatabase to a geodatabase on my ...
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1answer
696 views

How to visualize azimuthal data with uncertainties?

I am trying to make a figure showing azimuthal data with a different range of uncertainties at each point. This oldschool figure from a 1991 paper captures the "bowtie plot" idea that I'm aiming for: ...
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1answer
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Is it possible to take automatically a “screenshot” of my selected feature in QGIS using Python?

I am implementing a tool which allows the user to create a profile of a feature (in my case urban parcels). Is it possible to automatically take a screenshot of this feature (displayed in a QGIS ...
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Is there a way to access QGIS plugins in Python?

Is there a way to access QGIS plugins in Python? I'd like to write a script to do some geoprocessing, and I'd like to use the clip, regular points and convex hull tools in fTools, as well as the Road ...
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What software to use for making digital elevation models from UAV aerial imagery?

I have a an unmanned aerial vehicle (UAV, also called a drone) and would like to use it to create a digital elevation model and orthomosaic over a smaller area (10 km2). My platform will be able to ...
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Aggregating Polygons To Meet Privacy Requirements

I have a point feature class representing office locations of all employers in a certain industry. The feature class has an attribute for storing the number of employees working at each office. ...
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Is there a way to use ArcPy and PyGRASS tools in the same Python script?

I´m trying to write a Python script, that includes different ArcPy / ArcGIS commands and want to combine it with GRASS geoprocessing tools. Unfortunately importing the GRASS libraries doesn´t work. ...
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Gdal Dataset.ReadAsArray() crashes Python

I am using Python 2.6.5 (32bit) with Numpy 1.3 and Gdal 1.9.1 installed on Windows 7 64bit. I am trying to read an 800 MB Imagine (.img) raster dataset into a Numpy array to do some raster algebra, ...
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1answer
550 views

OGR/GDAL threading results in low core utilization

I'm trying to process some raster data using ogr/gdal and I can't seem to get full utilization of all the cores on my machine. When I only run the process on a single core, I get 100% utilization of ...
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4answers
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ArcGIS 10.0 Python SearchCursor file locking

I have a script that gets a value from a shapefile's field to return to the user. It seems that only when the arcpy.SearchCursor is called ArcMap locks the file and it doesn't get removed after the ...
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302 views

Determine minimum number of polygons from shapefile to cover an area of interest

I have a large number shapefiles representing areas of interest for an analysis that will be conducted using various sources of satellite imagery (IKONOS, RapidEye, etc.). Unfortunately, the imagery ...
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1answer
466 views

PyQGIS file lock release

I was wondering what triggers the release of file locks in pyQGIS? I am trying to delete a few data sources (used temporarily) by calling QgsVectorFileWriter.deleteShapeFile, but I have to quit QGIS ...
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798 views

Metadata -auto build using python

We have a large (10,000 plus) repository of spatial data (shp/gdb/tab vectors and ecw/tif rasters and also las, xyz and DEM data) where some have metadata records in xml using anzlic metadata editor. ...
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686 views

How to implement MultiValue Parameter with Multiple Columns?

This might be a simple question, but I haven't been able to find a straightforward answer. I'm working on an ArcGIS (9.3) Python script. One of the inputs is a list of features. For each feature, I ...
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1answer
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Exit script with Python

I've got a Python script for ArcGIS that I'm working on, and I'd like to have the ability to have the script quit if it doesn't have the necessary data available. I tried a straight up sys.exit() but ...
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4answers
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how can i convert a shapefile to lat and lon boundaries?

i have a shapefile of country subdivisions and i would like to extract an array of bounding lat and lon for each division.. is it possible to do?
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how to overlay shapefile and raster?

I have a shapefile with polygons. And I have a global raster file. I want to overlay the shapefile's polygons onto the raster grid and calculate the mean raster value for each polygon. How can I do ...
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Python scripts that run inside ArcMap vs ones that run outside?

I'm just starting to get into Python scripting for work.. I'm currently creating a script to automate a process. Basically, it asks the user the client name, gets a projection if available, creates ...
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Compiling Python Scripts that use ArcGIS Geoprocessing Tools?

I've been coding with Python for several months now and have developed some reasonably complex scripts for primarily geoprocessing tasks. That being said, I'm still learning a lot as I'm coming from a ...
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How to bypass errors in arcpy for/while loop?

I have a handy script tool that loops through a workspace and renames and copies shapefiles to a feature dataset. However, if there is a corrupted shapefile somewhere in the workspace the script ...
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ArcGIS/ArcPy Python, how to get latitude and longitude of a projected point?

I have a point feature in a feature class that is being accessed by ArcPy. The point is projected but I need to find an efficient means to get the unprojected latitude and longitude for this point. ...
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5answers
534 views

How to improve performance when using ArcGIS cursors in Python with big tables?

I have a pretty big point feature class in a file geodatabase (~4 000 000 records). This is a regular grid of points with a 100m resolution. I need to perform a kind of generalization on this layer. ...
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2answers
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How to get list of selected features in ArcGIS for Desktop using Python code?

I have a question regarding selections in ArcGIS for Desktop. Assumed I have one layer in ArcMap and I have selected two of five features. Is it possible to get a list of all selected features by ...
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How to list feature classes in multiple geodatabases in a folder?

I have a folder with numerous geodatabases in it. Within the geodatabases are feature classes. I would like to get a list of the feature classes in these geodatabases using a Python script. I've only ...
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3answers
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Get all vertices of a polygon using OGR and Python

I'm having a little trouble with the Python OGR API. What I am trying to do is get all the coordinates of each vertex of the outer ring of a polygon. This is what I have so far: import osgeo.ogr ...
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4answers
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How to change feature class and field aliases in bulk?

I have over a hundred FCs, each with 10 or 20 attributes to add or change the aliases for, two or more times a year. Needless to say, this is not something I'm going to grunt my way through. How can I ...
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Creating table containing all filenames (and possibly metadata) in File Geodatabase?

I need to create a metadata-table for all files in a File Geodatabase or Spatial Database. It would be awesome if it were possible to automatically be updated with new filenames, and possibly even ...
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How to Batch Clip in ArcGIS Desktop 10 using Python/ArcPy?

I've come across a few similar questions for older versions of ArcGIS, but haven't found a suitable answer for ArcGIS 10. I have two polygon shapefiles that cover a large area (e.g. an entire ...
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3answers
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Speeding up Python calculated timestamp field in ArcGIS Desktop?

I am new to Python and have started to create scripts for ArcGIS workflows. I am wondering how I can speed up my code to generate an "Hours" double numeric field from a timestamp field. I start with ...
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673 views

How to programmatically check if the number of shapes = number of table records?

I have a handful of approximately 1000 shapefiles that are corrupted (see attached error message). The shapefiles were generated from eCognition Developer 8. There is a script tool that seems to ...
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using shapely: translating between Polygons and MultiPolygons

[EDIT: the solution to this was simply to use OGR to read shapefiles. See geographika's example.] In an ESRI shapefile, there is no distinction between Polygons and MultiPolygons. Furthermore, there ...