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

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Min value (OD Cost Matrix)

I have an attribute table with columns that I have gained from running an OD Cost Matrix. In one column named "Total Minutes" I will select the lowest value (the shortest route). Then I will create a ...
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10 views

In QGIS Process Modeller, is it possible to automatically run a function on several layers without listing all combinations?

Trying to develop a Model which includes finding any intersections between layers and then merging them all into a single layer. I have 12 layers in total, it's not really efficient to list all the ...
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0answers
32 views

Decompress a LZW-compressed GeoTIFF

I have a LZW-compressed GeoTIFF file and would like to split it into several smaller regional files and change the format to png. I tried to do the spliting with gdal_translate -srcwin. I only get a ...
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1answer
38 views

arcpy absolute file path failing with AddLayer()

I have the following code: import arcpy.mapping as mapping mxd = mapping.MapDocument("current") print mxd.title df = mapping.ListDataFrames(mxd)[0] print df.name layer = ...
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1answer
44 views

Can we access the ArcMap Image Analysis tools using Python?

Esri recently added a new Image Analysis window to ArcMap - it's found under > Windows in the main toolbar: The Image Analysis window's Processing section simplifies the experience of applying ...
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1answer
54 views

Using Python in Field Calculator to compare two fields

I'm trying to use field calculator to compare two fields in a table of tax parcel data, Land Value (LAND_VAL) and Improvement Value (IMPRVT_VAL). My goal is to determine (1) Parcels with land value ...
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23 views

How to calculate the area of an ellipse on the earth's surface using Python?

I have a dataset consisting of GPS coordinates. I use a clustering algorithm to generate a two dimensional Gaussian for me. The Gaussian takes the shape of an ellipse if visualized on the map. ...
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36 views

How can a script tool share (dynamic) variables among different modules?

I'm running a python script from the toolbox window (as a script tool). I have a second python (tkinter) module that I use as an input interface. Now, I know that the script tool can call the ...
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1answer
65 views

QGis: scripting the map rendering (multiple similar maps from one shapefile)

I would like to ask for advice on creating a Python script that will provide the opportunity to render a plenty of similar maps (with the same extent, projection, layout, color scheme and composition, ...
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1answer
45 views

Finding closest Intersection between line strings (PostGIS)

I want to find the distance between one point (excavation sites) and a line (rivers) for the cardinal directions. What I thought would be the easiest way is to draw lines between the excavation site ...
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2answers
53 views

Is it possible to publish a map service from an SD File purely over REST (no arcpy)?

I want to automate the publishing of map services, but without using the arcpy library. Is it possible to publish a map service from an .SD File purely over REST (no arcpy)?
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4answers
94 views

Field calculator Python else statement question

The codeblock below is run on Field1 and calculates Field1 to equal Field2 if they are not equal. Else it returns Field1. My question is, does the else statement actually recalculate Field1 to equal ...
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2answers
44 views

Adding layer into ArcMap via Python - .pyt versus .py

In the final step of a script I've built, I'm trying to add a layer into an empty blank map document. This is my block of python code below that adds the layer. Everything works fine if its run from ...
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2answers
36 views

How to add data to a newly created folder using arcpy?

I'm writing a script to create a new folder and then copy a feature class to a shapefile and add the shapefile in the new folder. The folder gets created but the script is failing on the feature class ...
2
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2answers
51 views

Memory and Processing Efficient Approach to Read a Timeseries in Python

I am trying to store a timeseries of high resolution raster images containing NDVI values into a dictionary for calculations. I am curious as to which approach may the most efficient when loading ...
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1answer
58 views

How to obtain the maximum/minimum longitude and latitude for a polygon?

I have the MSA/CMSA shape file which contains 274 metropolitan areas. How do I have to obtain the maximum/minimum longitude and latitude for an area? So, it's like drawing a box right outside and ...
2
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2answers
62 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 ...
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1answer
25 views

PGRouting Layer plugin error in QGIS 2.2

I am trying to do some basic computations using the PGRouting plugin for QGIS, but I am getting this error all time: An error has occured while executing Python code: Traceback (most recent call ...
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4answers
106 views

Issue with UpdateCursor and if/else statement

I have been working on this code for awhile and I can't make it work the way I need it to. The code is suppose to move a feature according to a set distance from types in a designated field. As the ...
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1answer
34 views

Split Large GeoTIFF to smaller regions with python and gdal

I have quite a large GeoTIFF-file (compressed 50MB but unpacked 6GB) and want to split it into several smaller regional files. Therefor I am using python. As I am a new gdal user I do not really have ...
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2answers
48 views

Getting time dimension from a GRIB file

I have a GRIB file from NOAA that contains several variables for a specific subregion in Norht-East Atlantic. I'm using ECMWF grip-api Python library to parse the file. While I'm able to get the ...
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0answers
35 views

Problem reducing the width of the attributes fields of a shapefile using python

I have a shapefile with rather long attribute widths (which is resulting in a rather large file). I am trying to trim it in python, here is my code: layer = qgis.utils.iface.activeLayer() ...
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1answer
30 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 = ...
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52 views

How to convert .shp file to zip file with mapnik?

I am creating android application for campus indoor map. I research so much think.I decide use osmdroid. I write here what I have done 1) I draw indoor map with JOSM. 2) I convert file.osm file to ...
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17 views

Does a road connect one grid cell to an adjacent grid cell?

So here is the problem I am working on. I have an OpenStreetMap roadmap which I overlaid with a 2-D cartesian grid. So for a given grid square, I want to find out if a road segment continues from the ...
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20 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 ...
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1answer
75 views

Null value error with Python in field calculator

I'm trying to calculate the angle between two line segments in ArcMap 10.0. I have a point shapefile, so I'm using the xy coordinates of 3 successive points to calculate the angle. I'm trying to use ...
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2answers
51 views

Counting Characters using Field Calculator - Arcmap

I am trying to use field calculator to populate a column based on the the number of characters in another column. I am using the Python Parser. I am not sure if the .count() function is appropriate in ...
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2answers
44 views

Whats a Python Script/Method to use to get the number of fields with data in an attribute table?

I am doing some data migration and need the number of records with actual data, sans null and blank fields, without switching back and forth with select by attribute. Ideally I would like to run a ...
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0answers
39 views

using arcpy to query sde database in python

I have three variables: view_name, column_name, and column_content. column_name contains id, name, address, etc. column_content contains 123, John, 200 King st, etc. user specifies the column_name ...
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2answers
32 views

Update raster value to reflect total number of points within cell- python

I have what should be a fairly simple task, but I can't seem to figure out how to do it. I have to do it in python/arcpy/gdal/whatever because I'm trying to automate this process for a hundred or so ...
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1answer
25 views

MakeXYEventLayer_management not creating final file?

I'm using python to generate x and y coordinates for the start and end of lines in Arc. I have successfully done this part but when I try and generate the nodes I have no idea where the output file ...
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1answer
27 views

CalculateField_management - updating fields with X and Y coordinates for start and end of line

I've searched all the help documents and can't see where my script is going wrong. I've tried adding the fields as FLOAT, replacing "PYTHON_9_3" with just "PYTHON" but it just doesn't work. The ...
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1answer
41 views

How to obtain the width and height of an image using arcpy

This Stack Overflow question shows how to obtain the pixel dimensions of an image using Python. Is it possible to find an image's height and width using arcpy and ArcGIS? arcpy.Describe would seem ...
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0answers
26 views

How to intersect widget using script python arcpy and geoprocessing service? [closed]

Is it possible to develop an intersection widget with geoprocessing service using script python arcpy? I try to do that with ModelBuilder but after publishing, in geoprocessing service i don't find ...
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0answers
24 views

Check if Openlayer Layer is empty, caused by nonexistence of internet connection?

I use Openlayer Google street map as a base-map in my QGIS plugin projects. i want to check programatically if the layer is loaded or is empty and decide if i load my offline base-map instead of ...
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1answer
44 views

Gdal creating raster rotated wrong way

I have been trying to read in a stack of images for a timeseries and created an output raster that contains the max pixel values of the timeseries. The arrays were created using numpy img_stack = ...
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2answers
107 views

Import CSV column into existing feature using arcpy

My goal is to take a CSV that contains 50 rows and one column and import the data into a feature class with over 3,000 rows using arcpy. I want to pick a random row from the CSV and then iterate ...
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1answer
51 views

Python in ArcGIS, CalculateField_management, updating with single value

I have a float field which I want to simply update all values with 1. I can easily do this within the field calculator but I have started using python today, what is the syntax to simply update a ...
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45 views

Intersecting Polygons

I have 10 shape files containing polygon features. I would like to produce a single polygon layer containing portions of the input polygons where no fewer than two of the aforementioned feature ...
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3answers
67 views

Filtered list in ArcGIS toolbox

My goal is to grab a bunch of feature classes, select the first feature class, list the fields, and return that list to parameter 1 as a filtered list. My ArcGIS toolbox is setup with 2 parameters. ...
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1answer
16 views

GRASS module g.mremove returns irrational outputs

I want to use g.mremove to remove multiple files in my mapset, import os import sys sys.path.append(os.path.join(os.environ['GISBASE'], 'etc', 'python')) import grass.script as g import ...
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1answer
45 views

How to create a dock widget correctly in QGIS plugin?

I am building a QGIS plugin and would like to use a dock widget. I have used QT creator to design the UI, with the object type being a QDockWidget. When the plugin is enabled in QGIS the dockwidget ...
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1answer
32 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 ...
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0answers
16 views

Using iface.showAttributeTable() on QgsVectorLayer retrieved by getObject()

I'm unsure if i'm properly using the processing.getObject() function. I'm creating a python processing script for QGIS 2.0 and 2.2, but can't seem to get an attribute table to open programmatically. ...
3
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2answers
204 views

Looking for Python module to do lat lon calculations

I'm looking for a Python module that can provide some / all of the following services using latitude/longitude to define points: Distance between two points Point in polygon Distance along a ...
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45 views

Issue blocking QGIS feature form dialog with Python

I'm not sure where I'm going wrong with this python logic for a custom form in QGIS 2.0.1. There are a few things required by the validation function: that index of combo boxes aren't 0 (first index ...
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1answer
29 views

Select by attributes within the fiona Python module

Is it possible to select polygons from a shapefile based upon their attributes using the Fiona Python module? I can't seem to find anything in the docs, but it seems like a strange thing not to be ...
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0answers
27 views

QGIS Plugin: Show a symbol at coordinates

I want to code a plugin for QGIS showing a specifig image (e.g. a .png or .ico file in the file system) at given coordinates. The background is, that I'm receiving coordinates and other information ...
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1answer
37 views

Processing Script: now gives error in QGIS 2.2

I recently updated to QGIS version 2.2, and am now getting an error when running Processing scripts that worked previously (in version 2.0.1). Uncaught error while executing algorithm Traceback (most ...