Questions tagged [python]

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

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I think I have problem with basics about FME and Python

I try to learn from Oliver's corner instruction ftp://ftp.safe.com/fme/pyfme/OliversCorner.zip) . So for example I overwrite his #script 4 to StartupPython Script some below and set input data in ...
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1answer
1k views

script for automating insert scale bar, text, north arrow

I've always wanted an automatic process for these tools instead of having to click insert again and again. It seems easy but I can't do it in modelbuilder and I can't seem to find anyone making a ...
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2answers
1k views

Lightweight python modules to convert LAS data formats to text formats?

I searched on the net and found pyLAS, but it seems to require quite a few other modules and I couldn't get the install right. Any pointers will be much appreciated.
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1answer
236 views

Where should I save my external python script to be executed in FME? [closed]

I need a path, because there are so many folders and subfolders :) FME is installed C:\apps\FME\python Tnx,
6
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1answer
3k views

How to filter wrong GPS readings?

I have absolutely no experience with GIS, it just so happens that one of the hobby projects I am doing at the local hackerspace includes tracking a model boat with a GPS... I hope this is the right ...
5
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1answer
2k views

Find distance and heading from a point to a polygon in lat, lon coordinates

I have counties mapped using polygons in Shapely with latitude/longitude for coordinates. Given a complex polygon x and single point y, how would I find the shortest distance between x and y as well ...
4
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1answer
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A count of points within a set distance using updatecursor

I have a script that calculates the average distance between points. What I want is to rewrite it so I can input the point layer, input a distance, and the output field will tell me a count of the ...
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1answer
1k views

Hotlink vector/raster files to open in current workspace in ArcGIS 10 similar to MapInfo

I want to add datasets to ArcMap and place them in a particular group layer by simply clicking on hotlinked polygons in a shapefile. The same process is easy in MapInfo and I want to implement the ...
2
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1answer
554 views

Why does this python function return a value of 0 in field calculator?

I am trying to calculate the percentage of a total which the median value makes. I have a column with the median column labelled (i.e. 1st,2nd,3rd,4th column is median), the columns of values and the ...
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1answer
805 views

arcpy.sa.Viewshed with OFFSETA

This is using ArcGIS10 arcpy with spatial analyst. I need to call Viewshed, but with an observer height set. I have tried using a Z-aware point feature set, but that only throws an error. I am ...
5
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2answers
820 views

select by attribute on shapefiles with open-source python modules

I usually use ArcGis 9.3.1, but when running a python script that includes Select_by_attribute (from gp), the script runs very very slowly. Is there a way I can perform a select-by-attribute on a ...
5
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4answers
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Automate Projection of multiple shp files using ArcPy

I have been trying to create a Python script that will convert all shape files within a folder from GCS WGS 84 to Web Mercator. Below is the code I have so far but what I'm struggling with is how to ...
2
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1answer
662 views

Calculating beta-diversity w raster data [renamed]

Using ArcGIS 10, it is not possible to generate a raster attribute table for 32-bit float values. Instead, I have tried the RasterToNumPyArray method, which crashes since the file input raster is so ...
3
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1answer
558 views

Create polygon from OGREnvelope

I have a folder full of about 2000 files and I would like to generate a kind of key map for each file so people don't need to just randomly load each one in order to find what is what. I have the ...
2
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2answers
1k views

Convert CSV files into OSM with FME

I have a database which i've exported as individual csv files for each table. Below are some of the attributes which exist from two of the csv files: wayPointID linkID order x y z length ...
6
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1answer
417 views

Seeing QGIS Python Commands

When learning MapBasic I found the most useful way to learn how to do certain tasks was to do them using the GUI and then watch the MapBasic window in MapInfo to see how they were achieved in code. It ...
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2answers
5k views

Getting print statements in Python script to print through a batch file

I'm starting to learn Python and batch files. I have a Python script which selects data by location and exports the selection to a new feature class. The script runs just fine - included in this ...
5
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2answers
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Python script using SAGA and arcpy for converting 'on the fly' LAS point cloud to shapefile? [closed]

Summary: I have created a process to import a LAS point cloud, clip it, select the ground points and save the output as an XYZ.txt for clients to use. This uses a python based script (will become a ...
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1answer
2k views

It is possible to edit selected features with Python?

I'm trying to edit some fields of the selected features in ArcMap. It's possible to do this with Python (ArcPy)?
6
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1answer
157 views

Would it be possible to construct a stand-alone grass.script python package?

I would like to migrate dependency on ArcPy to grass.script without requiring the full installation of Grass. Would it be technically possible to have a portable directory containing grass.script and ...
2
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1answer
3k views

Using a geodjango PointField with geography=True, my distance calculations are wrong

Here's my model: class ExchangeArea(models.Model): """ An Exchange Service Area, calculated from a phone exchange and surrounding census tracts. """ coordinates = models.PointField(...
0
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1answer
213 views

How do I assign a variable to a SQL Server ArcSDE database's feature class?

I'm using ArcGIS Desktop 10 and have no experience using Python with a SQL Server ArcSDE database. When using a shp file or file gdb it is very simple to reference a given feature class by simply ...
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2answers
1k views

Parameterized insert query to PostGIS fails

I have a PostGIS database table that I need to insert data into. I'm using Python 3 and the pg8000 interface to Postgres. Somehow, parameterized inserts do not work. If I do iq="INSERT INTO points(...
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1answer
1k views

How to determine area of pixel in meters with GDAL and Python?

I have a raster loaded in Python using GDAL bindings. I'd like to be able to determine the area of a pixel in meters although I'm not confident that the projection is in meters. On this page I see a ...
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2answers
1k views

Unzip a file using python caller in FME 2011

The idea is to download a zipped file from a website and unzip it using FME 2011. I have attached a screenshot of FME workbench which is not working.
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3answers
3k views

Writing SQL WHERE Clause using Multiple Choice values in FME?

I published a parameter which is of Choice Multiple type. I wish to use values from this parameter for WHERE Clause when Reading Inputed Data in the begin of Workbench. So there is no problem if I ...
2
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1answer
931 views

Running C# code from Python tool for ArcMap?

It appears that the only way to copy individual rows of data while preserving GlobalIDs in code is by using C# or VB.NET. I need to run the C# code from the above link within a python tool, and I am ...
6
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1answer
1k views

Mapnik/Python Compatibility

Anyone know what versions of Python Mapnik is compatible with? I'm having trouble getting Mapnik to work. I'm thinking it might be because I am on 64-bit Win 7 and installed the 64-bit Python (v2.7) ...
11
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3answers
2k views

Downloading and processing raster files in Python? [closed]

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 ...
3
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1answer
636 views

Want to use GDAL in Arc10 toolbox via subprocess call

I'm attempting to launch a version Python 2.5 that supports GDAL from an ArcGIS10 toolbox script. I'm doing this because I'm having loads of trouble importing the GDAL library directly into Arc, and I'...
6
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2answers
5k views

GDAL Python bindings not picking up OGR PostgreSQL driver

I have a windows server (Microsoft Windows Server 2003) with: Python 2.7, PostgreSQL 9.04-1, GDAL 1.8.1 (installed from the windows installer (gdal-18-1500-core.msi) hosted at http://vbkto.dyndns....
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1answer
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How do I 'select' using ArcPy?

When using a cursor to loop through an attribute table, is it possible to iteratively select each row? I want to clip a line to a polygon grid (see previous question); due to the size of the grid the ...
4
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2answers
1k views

How to merge street layers in QGIS for exporting to PostGIS?

Is there any way of merging lots of street data in QGIS and getting one layer for exporting it to Postgresql? I know one method using mmqgis "Merge Layer" tool. It works in Ubuntu but not in Windows....
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1answer
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How to solve an installation problem involving QGIS, Python, and a plug-in?

In an attempt to get the plugin "Profile Tool" working, I installed geoslib and python Shapely 1.2.10 module as requested using following: sudo port install geos Then install Shapely once downloaded:...
3
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2answers
3k views

How to translate (reposition) a raster in Python?

I tried to use QGIS GeoReferencer to translate a raster layer, but somehow failed. It just goes to somewhere unexpected. Now I decide to do it myself, with python. I think some libraries like GDAL ...
5
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2answers
661 views

Finding Raster Overlap within a Directory

Here is the scenario: I have a directory with 100+ map projected, single band, rasters that weighs in a 40GB+. I have used ArcMap's built-in mosaicing tools to create a raster mosaic. I am using a ...
13
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5answers
5k views

Python, shapely library: is it possible to do an affine operation on shape polygon?

I am trying to create a rotated rectangle in lat/lon coordinates. Basically, I have the coordinates of the center and rotation angle around the center. Is it possible to do using, shapely or gdal, ...
6
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5answers
20k views

How do you test for a NULL string field in the Field Calculator with Python?

I am trying to perform an operation on a string field with a condition that it contains data. Referencing None with Python does not appear to work when the field is nullable and contains <Null> ...
6
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4answers
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Does File Geodatabase performance degrade as it fills up?

I'm having a memory leak issue. Upon investigating this more, it seems the file based geodatabase I write to in a loop, is growing very large, and as it grows, it significantly degrades the ...
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4answers
942 views

How to unproject a shapefile in Python?

I have one shapefile with XY coordinates in meters. Now, I want to develop one script in Python which converts meters to decimal degrees. Please help me to develop this. Thanks
9
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4answers
2k views

Use Esri Geoservices REST as backend for Python web framework (Django?)

I would like to know if it's feasible to use an existing Python web framework such as Django/GeoDjango as a frontend to work with Esri's Geoservices REST API? I envision developing a database engine ...
3
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1answer
613 views

Adding Descriptions to custom ArcToolbox 9.3.1

I looked http://webhelp.esri.com/arcgiSDEsktop/9.3/index.cfm?TopicName=Setting_script_tool_parameters and couldn't find how to add Descriptions for each parameter in the script tool. I see how to add ...
7
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1answer
303 views

Efficient Network Neighbors?

I would like to identify the Kth order neighbors of an edge on a network, specifically the neighbors of a large set of streets. For example, I have a street that I'm interested in looking at, call ...
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0answers
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arcgis server 10, vb.net, non pooled service, web adf

i am running arcgis server 10. i created a A.MXD file, then started arcgis server and successfully added non-pooled service using A.MXD. i also installed visual web developer 2010 express and created ...
2
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1answer
202 views

ArcGIS 10 SP2 issue with AggregatePoints

Esri persuaded us to upgrade to SP2 and now we cannot use the code we have, as it doesn't work. According to the download material, NIM063853 is when AggregatePoints doesn't create the derived ...
2
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0answers
269 views

RT Sql Layer plugin giving an error [closed]

I am trying to use the aforementioned plugin with QGIS 1.7 and Postgres 9.0/PostGIS 1.5. Added a PostGIS spatial layer w/out a problem and then clicked on the RT Sql layer button which displayed the ...
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1answer
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How to update only a single vector layer in QGIS map canvas?

I want to update a single vector layer as I am working on 8 vector layers and they are getting fast data from serial port so for updating I use mapCanvas().refresh() which refresh all the layer and I ...
3
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2answers
1k views

PostGIS + pgRouting: Adding dummy links to a road network and performing routing analysis

I'm a beginner when it comes to postgis and pgrouting development. For a project I'm working on and a bit of the algorithm: I have a polygon layer that represents zones I have a line layer that ...
3
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2answers
6k views

Loop through records

I have written a python script that is supposed to basically loop through selected records of a feature class. Here's a sample of what a table looks like: OBID STID FL TL 1 1 0 9 ...
8
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1answer
355 views

Optimize GEOSGeometry's spatial operations by avoiding thread-safety checks

A ranking algorithm I'm developing for a Django webapp requires performing spatial operations (within, intersections, sym_difference, etc.) using a query against large number of geometry objects. ...

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