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

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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
580 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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3answers
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How to round a column in attribute table (ArcMap)

I want to use the Field Calculator in ArcMap to round an existing column to two decimals. Currently I have a column that is 6 decimal places long and would like to simply round it down to 2 decimals. ...
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2answers
4k views

Finding mid-point of line using ArcPy?

How can the mid-point of a polyline be calculated using the geoprocessing framework, e.g. in a Python script? The polyline.centroid property returns The true centroid if it is within or on the ...
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2answers
560 views

How to add different sized rasters in GDAL so the result is only in the intersected region

I'm writing a Python method that adds two rasters and generates a single raster output. For reasons beyond my control, the extents of the input rasters are different, but they do overlap. Is it ...
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2answers
6k views

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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1answer
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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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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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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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6answers
802 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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How to Remove return/newline (\n) character from Field using Python and Field Calculator?

I have a geodatabase table with a field that I'm trying to remove return characters (new line). I found this post (How can I remove (chomp) a newline in Python?) of how to do it, however it is not ...
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4answers
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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 ...
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4answers
785 views

How to use PostGIS to handle complex geoprocessing workflows?

Our organization is considering moving our geoprocessing workflow to PostGIS. We are currently using ArcGIS, with a plethora of custom Python tools used in ModelBuilder. We're moving most of our data ...
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1answer
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Polygon overlay with Shapely

I'm trying to capture all the non-overlapping polygons indicated below using Shapely (given polygons A,B & C). Moreover, I'm hoping to do so without iteration, testing for intersect etc. The ...
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1answer
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How to create a script tool that will create a copy of a feature class and offset it by a given distance? (arcpy)

I want to duplicate a polygon feature class and offset all of the polygons by about 10 feet in both the x and y directions. I asked if there was any way to do this last week, and I was informed that I ...
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1answer
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GDAL/Python: How do I get coordinate system name from SpatialReference?

In Python, using GDAL, I've extracted a raster's projection as a WKT string as follows: wkt = dataset.GetProjection() # wkt is ...
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5answers
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How to convert line simple features to topological network?

using Gdal/ OGR is there a way to convert a shp, kml, or PostGIS line layer into a network of nodes and segments so it can be used in packages such as networkx?
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1answer
907 views

Import GRASS and SAGA modules to python script

I'm new at this. I am "building" a python plugin for qgis and I want to import modules from GRASS and SAGA but I don't understand how to do it. The plugin I want to import is Kriging interpolation ...
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2answers
3k views

How to get raster corner coordinates using Python GDAL bindings?

Is there a way to get the corner coordinates (in degrees lat/long) from a raster file using gdal's Python bindings? A few searches online have convinced me that there is not, so I have developed a ...
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5answers
764 views

Raster diff: how to check if images have identical values?

Is there a means to check to see if any 2 given raster layers have identical content? We have a problem on our corporate shared storage volume: it's now so big that it takes over 3 days to conduct a ...
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1answer
202 views

The role of '#' in a python 'if':

I recently exported an ArcGIS model to python and was reviewing the script and am confused by the following line: if TRU_W_DatableFeatures == '#' or not TRU_W_DatableFeatures: I can't seem to find ...
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4answers
527 views

ArcView 3.x Avenue Bitmaps (Tabs?) vs. ArcView 10 Python Cursors

Note: While this question has an answer, any further tips for optimizing a cursor process would be greatly appreciated. I will be monitoring for any updates. Currently, my boss (who works in Avenue) ...
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2answers
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Measuring distance in spherical Mercator vs zoned UTM

I've got points in WGS84 lat/long and I'd like to measure "small" (less than say 5km) distances between them. I can use the haversine formula from http://www.movable-type.co.uk/scripts/latlong.html ...
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Can ArcGIS and OSGeo4W share the same python install?

I don't like unnecessary duplication. Is it possible to install python only once and have both ArcGIS and OSGeo4W use it?
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Inserting newlines in Rectangle Text elements via ArcPy causes overlap?

I ran across an issue the other day when I tried to use ArcPython's mapping module to edit rectangle text elements with newlines (\n) in an ArcMap document. Here's what the output looked like: ...
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3answers
374 views

Setting symbol descriptions of ArcMap layout legends from table?

ArcMap has the ability to show an extended description for each item in the symbol list. How can I populate that property from a table? The goal is to avoid having to edit each symbol one by one in ...
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2answers
868 views

Python, GDAL and building raster attribute tables

I have an integer raster for which I would like to build a raster attribute table using Python and GDAL. I can create a GDAL raster attribute table in Python as follows: >>> rat = ...
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2answers
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Error handling with python script in ArcGIS 10

I have a python script that I am using to create a list of all mxd files (with full pathing) in our Projects folder. The script then uses that to iterate through the list and do a ...
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1answer
956 views

How to read/write from/to QGIS project file using Python?

I'd like to save the project-dependent configuration of my Python plugin inside the QGIS project file. Is this possible and what are best practices to do so?
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1answer
573 views

Is there a way to properly have GDAL raise exceptions in Python?

I am working with GDAL in Python and have wanted to get GDAL to raise exceptions so that I can do something useful with them. For instance if a file cannot be opened with gdal.Open() I would like to ...
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3answers
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ArcGIS Python Tool - Importing Custom Script Into ToolValidator Class

I had posted a question last week about customizing a ToolValidator class and got some very good answers. In working with the proposed solutions, I have created a custom module that performs queries ...
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2answers
946 views

GeoTIFFs made in GDAL don't have min/max range when loaded in Arc/QGIS

I'm creating some floating point rasters in GDAL with the GeoTIFF driver. When I load the resulting images into QGIS or Arc the default symbology puts the min at -3.40282e38 and max to 3.40282e38, so ...
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3answers
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How to populate an undirected graph from PostGIS?

This question is more related to resources that I might not have identified yet, although I've been searching the web for a while. In the project I'm working at the moment I need to run a ...
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2answers
485 views

Best design for Open Source Python / PostGIS prototype

I am writing a data intensive web application that is delivered through apache. My question is about how to best arrange processing given that there are multiple options. I have at my disposal ...
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1answer
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Importing GDAL from Python window of ArcGIS for Desktop?

I am trying to run some Python code using the Python window in ArcGIS 10.1 that uses both the arcpy and gdal modules. However, when I try and import the gdal module I get an error: ImportError: No ...
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2answers
567 views

Generate near table for x number of neighbours using arcpy

There are 3 likely scenerios that I am trying to capture near distances for: An interchange subway station, which has 2 or more neighboring stations. That is, the station in question connects 2 or ...
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1answer
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Arcobjects in Python: assign interface to objects with feature (shape) geometry

I am trying to use ArcObject in Python. I do have problem with assigning an interface (i.e. IZ.InterpolateZsBetween) to my object with geometry data, code is: from Comtypes.client import ...
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2answers
790 views

Scriptable alternative to ArcScan (particularly vectorising lines within tolerances)

Sadly the answer to this question suggests that it is not possible to script ArcScan from within a python script. Therefore, does anyone know of any alternatives to ArcScan (either within ArcGIS, or ...
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1answer
315 views

How to call the interpolation plugin from the python console?

I would like to call the QGIS interpolation plugin function (TIN method) (Raster->Interpolate) from python console. I can't find the corresponding function within QGIS API or within the ...
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2answers
396 views

Can ArcGIS ModelBuilder open Excel file for manual editing, then feed those edits back into model?

I have been tasked with creating a model using ArcGIS ModelBuilder, that initially runs a couple of geoprocessing tasks, before then joining an Excel table to the result of those geoprocesses. ...
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1answer
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How to prompt for user input during ArcGIS Python script tool execution?

I want to prompt for user input after all parameters have been specified for the script tool. I've seen many forum posts and stackexchange questions about this, and they all conclude that it's ...
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1answer
826 views

Arcmap Select by Attribute with Python

I would like the following to select (highlight) the "project" layer that intersects the grid, and then pull a record from the selected "Grid". I do not need to save the layer. Note: Running the ...
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3answers
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Using variables from one Python script in other Python scripts?

I want to set up a single python file containing variables that have the locations of all my data sources. This would then be used by all my other scripts, then as a data source changes, I only have ...
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3answers
12k views

Define Workspace for SDE Connection in Python

How do we define SDE Connection for workspace in Python Scripting?
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4answers
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Subset Folder Contents ArcPy

I have about 1500 .txt files within a folder named 3410001ne => 3809962sw. I need to subset about 470 of these files to process with a Python script. Below is the section of code prior to my for ...
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2answers
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How does one access a featurelayer in SDE via Python?

I am trying to use Arcpy to run the CopyFeatures_management script so that I can copy a featurelayer in SDE. What do I use for the input (and output, for that matter, since I'll be copying the layer ...
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Who uses FME Python extension and how?

I saw a great interface to FME with Python What you guys are doing with it? I want ideas.
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How to access Esri ArcPy modules from Enthought Canopy?

I have ArcGIS 10.1 running on my windows system and I have also installed the new 32-bit Canopy Express Enthought Python Distribution. Is it possible to load and use the Esri ArcPy modules from ...
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How to find the locations of the highest values in a raster?

Using ArcGIS 10, I have a raster where I would like to find the pixel with the maximum value in the raster and return its location (center of pixel) in decimal degrees. I would like to iterate through ...