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

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How to fully load a raster into a numpy array?

I have been trying to check my filters on DEM raster for pattern recognition and it is always resulting in missing last rows and columns(like..20). I have tried with PIL library, image load. Then with ...
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4answers
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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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1answer
3k views

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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3answers
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How to convert LAS file to numpy array?

I have begun learning how to manipulate LAS data in python and wanted to see how others handle LAS files. I would like to read the points (I am using a numpy array), and filter out classes 1 and 2 ...
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2answers
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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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Programatically splitting polygon with line?

In looking at this question, it occurred to me that I am not sure how one would go about using geoprocessing tools in ArcGIS to split a polygon with a line programatically. Manually, you would use ...
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2answers
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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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2answers
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How to split shapefile per feature in Python using GDAL?

is it possible to split a shapefile per feature in python? (best would be a solution where i can temporarily save the resulting vector objects to the memory instead to disk). The reason: I want to ...
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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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2answers
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How to find differences between shapefiles?

Every month I have to QA/QC some streets data for an entire county (over 47,000 records). The first step is to compare the two files. Currently, I'm using a tool that was created in house via VBA ...
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1answer
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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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3answers
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How to smooth / “reinterpolate” a raster with GDAL?

Short: I want to change the resolution of a raster and smooth the gray ramp like shown in the images bellow. The preference is to use GDAL, PIL or Numpy. Description: I'm kriging points into rasters ...
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1answer
637 views

Teaching Python to Land Surveyors

Does anyone have any good examples of using Python to automate or simplify common surveying tasks? I'm teaching a Python/ArcPy lab this week for a GIS class. There are a number of surveying ...
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1answer
6k views

How to write standalone Python scripts using QGIS?

I've been learning how to use the Python Console in QGIS using references from qgisworkshop.org. I'm familiar with writing standalone scripts in ArcGIS and want to learn how to do the same with QGIS. ...
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3answers
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Exporting features with attachments for use 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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4answers
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Bilinear interpolation of point data on a raster in Python?

I have a raster that I'd like to do some point interpolations with. Here is where I'm at: from osgeo import gdal from numpy import array # Read raster source = gdal.Open('my_raster.tif') nx, ny = ...
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2answers
191 views

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
761 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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2answers
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Reprojecting WGS 1984 Web Mercator (EPSG:3857) in Python with GDAL

I am reprojecting rasters in python using GDAL. I need to project several tiffs from geographic WGS 84 coordinates to WGS 1984 Web Mercator (Auxiliary Sphere), in order to use them later in Openlayers ...
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5answers
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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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4answers
3k views

How to extract the number of vertices in each polygon?

I have ArcGIS Desktop 10.2 and my challenge is how to extract the of number vertices in each polygon for all features like this: I have many parcels in my feature class and I want to extract ...
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7answers
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How to get X Y coordinates and cell value of each pixel in a raster using Python?

I’m really new to Python and I would like to know whether there is a quick method to get cell values of a raster pixel by pixel and the coordinates (map X Y coordinate of centre of each pixel) using ...
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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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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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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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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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2answers
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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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3answers
7k views

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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5answers
721 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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6answers
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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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3answers
757 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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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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8answers
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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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2answers
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Creating a multispectral image from scratch

I want to make a multispectral image from cero to do some tests on it. Something really simple like 5 completely uniform bands with salt and pepper noise on them or a square of different values at the ...
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2answers
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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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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 using it?
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3answers
887 views

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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2answers
913 views

Is there a way to refresh imported modules in a ArcGIS Python Toolbox?

When using a python toolbox (.pyt) in ArcMap, I'll typically follow a pattern where the .pyt file itself is simply a wrapper to collect input arguments and define the tools themselves. Supporting ...
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1answer
189 views

How to save python session in QGIS?

After running a lot of scripts in QGIS' python console, I have more than 10 dictionaries and lists, and I need these for further analysis. Is there a way to save python session, with all these ...
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1answer
880 views

How to address the new “Task-Completed” QgsMessageBar in Python?

I am really amazed what huge steps the QGIS development has taken in the last months. The new iconset, the improved Print composer and many more changes to be seen in QGIS 2.0 are really awesome! ...
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317 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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1answer
881 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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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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2answers
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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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1answer
477 views

Running ArcGIS 10.0 Under Virtualenv

I am working on a Python package that has a mixture of command line tools and ArcToolbox tools. For Python development it is really useful to use VirtualEnv, especially when working with installers. ...
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1answer
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When iterating over a vector layer with pyqgis, how do I check whether a feature is selected?

While iterating over a vector layer using the following code (summerized from the example in the pyqgis cookbook), is there a way to check whether a feature is selected? provider = ...
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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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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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1answer
454 views

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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1answer
781 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 ...