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

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48 views

Convert Road layer shapefile into a graph

I'm going to use Astar algorithm to find a path between two selected points.And I used the following code for that.Is there any way I could convert my Road Layer shapefile into a graph, which can be ...
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89 views

QGIS 2.2.0 GRASS not worked

I use QGIS 2.2.0 on Windows 8 64 bit. I try to install use Standalone installer and OSGeo4W and still get the error And then i start GRASS C:\Program Files (x86)\GRASS 6.4.2>grass64 ╬╪╚┴╩└: ...
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1answer
77 views

flatten / collapse one-to-many table and keep the 'many' attributes separate

I have a data set that contains intersection data. Each intersection node has up to 6 links which is identified by IN_LINK and OUT_LINK attributes. I want to create a new dataset that includes the ...
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2answers
47 views

Problems searching for attributes

I've come across this problem a few times and have not been able to find a satisfactory answer. I am new to python though so perhaps I have not been looking in the right places! Anyway, In ArcGIS I ...
1
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1answer
36 views

How to add an interpolation raster from the python console in QGIS?

I'm trying to add an interpolation layer based on an existing vector layer by using the Python Console (initially in the menu Raster/Interpolation), but can't find anything related in the ...
0
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1answer
28 views

Set the parameter values retreved from database in Arcgis script tool in toolbox using python [closed]

I am now thinking a function to allow user to modify his information stored in the database. To do this, I developed 2 script tools in ArcGIS(10.2), One is the ask user to input his ID, the other one ...
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1answer
53 views

How to open QGIS using VBA?

Using VBA, I want to open QGIS (the actual GUI) and execute a simple script through the Python console or the editor.
0
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1answer
47 views

Change Attirbute Name (Fiona)

I have a shapefile that has 2 attributes named "X" and "Y". I want to change this to "Lon" and "Lat". My (limited) experience tells me that I should read in the original shapefile, preserve the ...
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31 views

Assigning a changing value to a variable in ArcMap using Python

I have two lists/strings/sets (the exact format can easily be changed) of values (u and v). I would like to do a cost distance analysis between each point in u and all points in v. For this, I need to ...
0
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2answers
106 views

How to make a routable graph from a Point and a Line shapefile, using Networkx?

I have one shapefile which consists of all the streets in the study area, and another shapefile which has points representing origins and destinations. I would like to know if it's possible to find ...
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2answers
66 views

Generating multiple visibility bearings in ArcGIS as automated procedure?

As a relative newbie to GIS, I'm quite sure there will be a way to do this in GIS (probably most efficiently by writing a python script!) but (to me anyway) this is a fairly complex thing to do and I ...
1
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1answer
98 views

How to make a Python script that does a task in QGIS?

When I run this code in QGIS Python console it works fine, but I want want to run it from an external Python script. What I want the script to do is: 1- Open QGIS 2- Run this code 3- Close QGIS from ...
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2answers
74 views

Open source, Python option for Arcpy's Con tool?

I'm wondering if there is a method to perform a function similar to Arc's Con tool, using open source options in python. I have two rasters, one that shows locations of clouds and the other is just a ...
0
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1answer
79 views

Writing shapefile with projection defined crashes fiona

I've just started trying to use Fiona to write out shapefiles. I found the example code below, which seems to work fine from shapely.geometry import mapping, Polygon import fiona # Here's an example ...
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1answer
31 views

QGIS Python - Executing functions for multiple directories

I would like the user to select 2 directories, each directory having their own defined algorithms. For example: First_Directory will add a column to all shapefiles in the chosen directory; ...
2
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1answer
106 views

Converting Matplotlib contour objects to Shapely objects

I would like to convert a Matplotlib contour collection to a Shapely geometry collection, in order to calculate the area contained within closed contour lines. it seems that all the information is ...
1
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1answer
51 views

how to assign keyboard key to python script in arcmap

I have a python script and I use it through my toolbox but I use it many times in a day. Is it possible to assign a keyboard shortcut to my tool ?
3
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1answer
63 views

Help with “projected XY to screen xy” conversion algorithm?

I'm trying to convert coordinates from any given coordinate system (be they the coordinates of a graph figure or a map, meaning they can span across both negative and positive values across any of the ...
5
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0answers
64 views

Competing approaches to line & polygon simplification

There seems to be a few theoretical options around at the moment for geometric simplification. Douglas–Peucker seems the most established, followed by Visvalingam's approach (used by d3.js). Now ...
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1answer
31 views

Problems running grass.mapcalc

I am using the GRASS Python Scripting Library on Ubuntu 14.04 with the packages available from the Universe repository. I have the following block of code: try: ...
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1answer
59 views

How to calculate monthly maxium values from daily data in a 365 band grd?

I have a MINT2005.grd file which has 365 bands representing days of year from 2005. Each band is a 32x35 matrix representing the temperature at different latitude and longitude pair. How do I ...
3
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1answer
137 views

How to find the distance to the nearest coastline from a land-based latitude/longitude point?

I'm completely new to GIS and unsure what I need to solve this problem: In the image above turquoise is actually land. Sea is white. I tried using the NASA Distance to the Nearest Coast data dump ...
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1answer
220 views

How to Properly Loop Through a List With a Cursor?

My team is working on a python script that does various updating tasks to our streets file. A part we are getting stuck on is trying to update a field. Currently we have a field FEDROUTE that is ...
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1answer
62 views

Is there a way to access the GeoProcessing tools in QGIS, in code

Is there a way to access the GeoProcessing tools in QGIS, in code? I want to find the Difference between two layers and make a new shapefile with the result.It can be manually done by selecting ...
0
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1answer
110 views

Python Field Calculator ArcGIS 10.1 expression question

I have gotten stuck on another seemingly simple arcgis field calculator python expression. I obtained a great answer to a another similar question a few years ago: Python Field Calculator ArcGIS 10 ...
2
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2answers
76 views

convert a shapefile into graph with nodes and edges

Is there a way to convert a shapefile into graph with nodes and edges(except networkx). I'm using qgis and I want to convert a road vector layer into a graph, so that I can use it to apply shortest ...
1
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1answer
38 views

assigning census block demographics to postal data (zip/zip+4)

Using Python and R, what would be the best strategy to tie Census Block-level data to zip/zip + 4? I understand we're not matching polygon boundaries (zip codes are not geographies), but somehow ...
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1answer
49 views

ArcGIS Geoprocessing “None Type” Second time

I am trying to publish an ArcGIS geoprocessing service in 10.2 I have a script setup that will run multiple times through Pycharm, but when I run it in ArcGIS it will run once and return this error: ...
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1answer
75 views

Does not show shortest path in networkx (in QGIS)

I used the following commands (in qgis console) to get the shortest path with astar algorithm. But the result shows 'NetworkXNoPath' every time. Why was that? Please help me to find a solution to this ...
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0answers
28 views

Is is possible to run the QGIS python module server side?

I'm pretty new to programming but I want to use the QGIS python module on a server. Basically I am trying to create a JPEG map programatically on a server. I already have a python script to create ...
2
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1answer
108 views

QGIS says “osgeo [python-gdal]” isn't installed on Mac

I know similar questions have been asked (like this one) -- but I'm encountering a unique problem. I installed GDAL complete 1.11 from KyngChaos, but when I open QGIS, I get the following error ...
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1answer
52 views

Locating 0-points multipart polygons using arcpy

By Running this piece of code: import arcpy arcpy.env.workspace = "C:\working\GEODATABASES\\tests.gdb" fcList = arcpy.ListFeatureClasses() for fc in fcList: with arcpy.da.SearchCursor(fc, ...
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0answers
32 views

QGIS r.cost / r.drain and errors

I'm trying to find the optimal route of several archaeological sites with Qgis 2.2. I've a DEM and r.walk or r.viewshed executed successfully, but r.cost always fails creating the output, however ...
2
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1answer
88 views

QGIS Python Scripting - Syntax definition

After playing around with the Model Builder and looking at the python scripts of what I make, I noticed some syntax which I can't find the definition anywhere. Here is a snippet of the python script ...
0
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1answer
31 views

PyQGIS: How to send signal to call unsetMapTool()

I've created a map tool to add some functionality to adding point features in QGIS 2.0. I'd like to unset this map tool if editing has manually been terminated by user. I've attempted as shown below, ...
0
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1answer
25 views

Add attributes to an output shapefile schema (via meta)

I am trying to copy the schema of an existing shapefile and add to it in an output shapefile. Somehow I am not getting anywhere with this...though the docs seem very clear (and the download page : ...
2
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2answers
53 views

GetCount raises exception

I opted to use gp.GetCount in my script. This raises an exception, though the process completes "successfully" while returning zero features (which is untrue). I'm wondering how this could be. Using ...
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0answers
29 views

How to get QGIS to play with pandas (Windows)?

has anybody been successful getting pandas to work with QGIS's Python installation, on Windows? I've used the OSGeo4W installer to install QGIS2.2, which comes with Python 2.7 and Numpy 1.5.1. Any ...
0
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0answers
39 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 ...
0
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3answers
106 views

Using ArcPy and Python to export Table View as PDF format?

I am using ArcPy to select from a layer and display the result on map as a table view. Now I want to export the table view as a PDF format. Anybody know about it? If it is beyond ArcPy to export ...
0
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0answers
54 views

PyQgis: How can I “append” features to a Vector Layer instead of “stacking” them?

As I read data from a text file and add points to a QgsVectorLayer (as well as related attributes), each new record gets 'stacked' on top of the previous one in the Attribute Table (and within the ...
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2answers
48 views

Issues Reading a table from Geodatabase

I have scripted a process to read a CSV file into a file geodatabase. Then, I want to read this imported file and work on it by adding new fields and calculating values. However, while using the ...
0
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1answer
72 views

Automating Intersect between two polygon layers

I have a spreadsheet that has county-level occurrences of around 1000 species within the US in the column headings (Species State County). Thus, for some counties there may be multiple species. I ...
1
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1answer
57 views

Iterating over selected features in QGIS Processing

I used to be able to iterate over selected features using the following script in v2.0. import processing features = processing.getfeatures(layer) for feature in features: #Do whatever you need ...
2
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0answers
51 views

How to detect turns of a route?

I'm doing a Python simulation of a vehicle, driving along a specified path. I generate dummy GPS readings, that fetch the current position of the vehicle, with some randomized error added. After a ...
0
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1answer
40 views

Blank Shapefile output?

When executing the following command string in the active browser, Qgis projects the triangle polygon and associated attribute table correctly. Upon reopening the shapefile in a new browser, the ...
1
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1answer
49 views

How do you determine when user is clicking the end point of an edit sketch using ArcObjects?

I am using vb.net working on ArcObjects. One requirement is to pop up a toolbox once the user click the end point (double click the point under editing status). So I want to know how can I know when ...
0
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1answer
52 views

Programmatically set layer properties Python Init function

Is it possible to set the layer properties Python Init function field programmatically? I've been looking through the qgis 2.2 api but can't seem to find anything on it. Hint, suggestions and ...
2
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2answers
96 views

Calculate Slope Between Pixels Through Time: A Time Series Trend Analysis

I have a 9 year weekly time series (~500 raster grids of equal cell size and extent). I'm interested in obtaining the regression line slope between pixels (Imagine stacking all 500 grids on top of ...
2
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1answer
123 views

How to surround a Polygon object with a corridor of specified width?

I'd like to build a corridor surrounding a polygon, so that the corridor's outer bounds all have the same distance to the inner bounds. Like this: I've made this lousy graphic in Paint, since I ...