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

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How do I programmatically update/recreate an ArcSDE feature class from external sql data?

I have an ArcSDE feature class that contains project points based on xy data from an external SQL databaes. (Not a geodb). I am looking for the best way to "recreate" the ArcSDE feature class from the ...
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5answers
4k views

Programmatically edit/update metadata in ArcGIS?

Has anyone succeeded in programmatically updating metadata in ArcGIS 10? Considering using Python/arcpy but ArcObjects (C# or Python/comtypes) is also a possibility. I need to update both the FGDC ...
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3answers
835 views

Why is this polygon “self intersected” and invalid?

I have a polygon defined as follows: segment from 43:29:02 N 003:50:39 E to 43:34:12 N 003:43:04 E arc(CW): center (43:34:49 N 003:58:16 E) from 43:34:12 N 003:43:04 E to 43:45:45 N 003:59:56 E ...
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2answers
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Call FWTools (ogr2ogr) from ArcGIS python script

In ArcGIS, I want to use a Python script (and a standard ArcGIS script tool UI) to call functionality from FWTools. How would I make the call to FWTools? I tried using ...
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1answer
373 views

Eliminating a column from a copied feature class via a fieldmap object in ArcGIS Python

The use case is exporting a feature class via a Python script (arcgisscripting v9.3x. Only a few of the columns are needed in the result feature class. I commonly use the fieldmappings/fieldmap ...
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2answers
4k views

How to export selected records to a .txt file

I am working on a project where I need to create a tool/method to export the attributes of selected features to a .txt file. I have point features containing addressing information, and the tool ...
4
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1answer
585 views

How to deal with direction (CW, CCW) of circles, in particular with shapely?

I am translating an input that describes zones by mixing segments and arcs. Arcs are given by a center, 2 points (beginning/end of arc) and a direction (CW or CCW). In a first prototypes using GDAL, I ...
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4answers
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Clustering Trajectories (GPS data of (x,y) points) and Mining the data

I've got 2 questions on analyzing a GPS dataset. 1) Extracting trajectories I have a huge database of recorded GPS coordinates of the form (latitude, longitude, date-time). According to date-time ...
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2answers
636 views

How to create GRASS scripts in C# in Windows

Most of the tutorials that I have seen are under Python and Linux. Is it Possible to create GRASS scripts in C# or atleast in Windows. I can create scripts using a different language as a compromise ...
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5answers
2k views

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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3answers
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How to create a circle in arcpy

Suppose I have a dataset where each record has an x,y and r (the centroid and radius of a circle). How can I create a polygon feature class containing parametric circles? Sorry to those who have a ...
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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 ...
4
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1answer
135 views

Is it possible to install 9.3 Desktop Administrator as a standalone program?

I have ArcServer 9.3 installed on a server that I use for running scheduled Python geoprocessing scripts. I have several running, and now I'm trying to schedule one to rec/post, delete and recreate ...
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4answers
9k views

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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1answer
583 views

How do I group layers in Mapnik?

I might be thinking about this all wrong, but right now I'm using Mapnik's OGC Server, and using that WMS with OpenLayers. How would I group multiple layers (say country, water, state borders) into ...
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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 ...
6
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5answers
7k views

Merge overlapping lines in ArcGIS

I have a polyline shapefile containing a number of lines, some of which overlap. By overlap, I mean that they follow exactly the same path for some of their route, but also have bits that are not ...
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2answers
7k views

How to divide a polygon into specific sizes using ArcGIS?

I have several thousand irregularly shaped polygons in a shapefile. I want to be able to split each polygon into three areas, and to specify what the size of those areas (they sum to the previous ...
9
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2answers
927 views

Scriptable alternative to ArcScan (particularly vectorising lines within tolerances)?

Sadly the answer to Can you access ArcScan from a python script? suggests that it is not possible to script ArcScan from within a python script. Therefore, does anyone know of any alternatives to ...
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3answers
2k views

Why would “import arcpy” hang Python script run from DOS/cmd prompt?

I have a very small test script (test.py) that I use to see if Python is installed and ready to use ArcPy. All it contains is: print "Starting" import os print "OS imported" import arcpy print "ArcPy ...
4
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2answers
2k views

Programmatically alter AliasName for fields defined in layer file (not underlying source)

Is there a way to alter the AliasName on a layer file only, and not the underlying shapefile or feature class? I have a few hundred layers that define joins between hundreds of tables with census data ...
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2answers
5k views

How should I use GDAL to perform a transformation?

Greetings, I am a student who wishes to use GDAL to transform a series of images from Lambert Conformal Conic (EPSG: 9802) to Google Earth's WGS 84 (EPSG: 4326) for a web mapping project. I know ...
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3answers
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ArcMap/ArcObjects - Drawing graphics onscreen: Explanation or tutorial for Draw/Refresh/PartialRefresh methods?

I find myself woefully lacking in understanding of when, why, and how (which type) to do screen draw/refresh/partial refresh. For instance, in a standalone Python script outside the application ...
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3answers
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Python, comtypes and ArcObjects: Error creating AppROT object

I am experimenting with comtypes and ArcObjects under Python 2.6.5 and ArcGIS 10 SP1. I'm using the pure Python method to wrap the ArcObjects OLBs described in this answer, but getting an error in the ...
4
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1answer
234 views

ArcObjects ITextSymbol.GetTextSize in Python: Why are the out params equal to 0?

This is related to the question I asked earlier about the syntax for this method under Python and comtypes. Now that I know the syntax and am trying to use it, the returned out params are equal to 0. ...
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1answer
980 views

ArcObjects: How to get from IFeatureClass on annotation feature class to IAnnoClass?

I am working in Python 2.6 and ArcGIS 10.0 through comtypes, so I have full ArcObjects access. (See the answer I tacked onto the related question "How do I access arcobjects from python?") That ...
3
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1answer
274 views

ArcObjects ITextSymbol.GetTextSize in Python: How do I define two input variables that get populated by the method?

I am using Python 2.6 and ArcObjects in ArcGIS 10.0 to build and draw, among other things, graphic text on the current display. At one point I need to use the ITextSymbol.GetTextSize method. In a ...
23
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6answers
19k views

Defining projections for multiple shapefiles in ArcMap?

I have over 100 shape files that don't have .prj file and thus when I bring them into ArcMap 10 they show the coordinate system as unknown. I know all of the shape files coordinate system is GCS WGS ...
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3answers
16k views

Python Question - how do I extract a part of a string [closed]

I'm building a tool in python and for that I have a question: I have a string such as "Denver.dwg Group Layer\Denver.dwg Annotation". How do I assign to a variable (for later print) only the first ...
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4answers
2k views

Best way to find the polygons crossed by a line

I'm trying to find all the polygons crossed by a single line (a GPS track). I'm using the OGR library (from python) for computing this, but it's currently a bit 'brute-force' (and slow). For every ...
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5answers
6k views

update one shapefile attribute table with values from another dbf table

I try to explain here what I am trying to do: I have one shapefile and one independent dbf table with the same fields. In the dbf table all the fields are populated but in the shapefile attribute ...
9
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1answer
2k views

automated georeferencing

I am attempting to fully automate the process of georeferencing a load of .png files - i have xml file containing the co-ordinates - but how can i use them? Does anyone have any advice?
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2answers
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selecting by attribute and specific value replace

I want to select all of the features by attribute where the attribue in myattrib is like... Selection "criteria H". That is not a problem. However then I need to replace (myattrib," H", "") except ...
8
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1answer
4k views

Problem with setValue() function in ArcGIS 10

I'm trying to add data to an attribute table in ArcGIS 10 using the following code: def make_floor_no( shapefile ): "Makes header for number of Floors (FLO) and calculates value" fieldName = ...
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2answers
334 views

Unique Character Generator Help

I am working on a script that will populate 3 letters into a field. I have to use letters due to field limitations and to make sure that I have enough combinations. I'm not really sure where I am ...
12
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4answers
2k views

Looking for a pythonic way to calculate the length of a WKT linestring

I was quite unsatisfied with Calculating Length of Linestrings in WGS84 in Miles. It kept me wondering if there is a more convenient, Pythonic way to calculate the length of a WKT linestring according ...
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5answers
2k views

how can i convert a shapefile to lat and lon boundaries?

i have a shapefile of country subdivisions and i would like to extract an array of bounding lat and lon for each division.. is it possible to do?
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6answers
615 views

Python for GIS on a thumb-drive

I'm looking at putting together a light Python install on a thumb drive that I can take to client offices and do some basic GIS processing. I'm thinking of installing the following: PyScripter ...
4
votes
2answers
301 views

Segmentation Fault (segfault) when using OGR CreateField() in Python

Receiving a segfault when running this very short script in Ubuntu. from osgeo import ogr, osr shpfile = 'Census_County_TIGER00_IN.shp' def cust_field(field): '''cust_field(shpfile, field) ...
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6answers
6k views

How can I calculate the orientation of each side of a polygon in ArcGIS 10?

I want to examine the orientation of each line in a polygon so that I can calculate their solar exposure. Each polygon represents a building, and has an associated height. For the moment, I just want ...
9
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3answers
1k views

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 ...
6
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1answer
1k views

Setting units in python using ArcGIS 10

I want to calculate the area of each polygon in a shapefile. How do I control what the units of measurement are? def getArea(shapefile): """Print area of polygons""" Rows = ...
7
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3answers
4k views

Problems setting up eclipse (with PyDev) for ArcGIS 10

I'm trying to use eclipse with PyDev to program in python. In Windows 7 x64, I've added a PATH environmental variable (PATH C:\Python26\ArcGIS10.0\python.exe;) and what I thought were the relevant ...
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15answers
22k views

Resources for learning Python programming with generic GIS goals in mind?

In your opinion, what is the best book/site to learn Python with GIS goals in mind? By "best", I mean: not very long (book) easy to understand (book/site) good practical examples (book/site) For ...
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1answer
611 views

GDAL Pixel Functions question

I am writing a program in python that converts raster files using gdal, and using VRT as an intermediate format. One of the things that i need to do is convert bands between different formats. I am ...
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7answers
2k views

How to implement value-by-alpha map in GIS?

I've been doing some background reading about cartograms recently and stumbled upon interesting alternative - value-by-alpha maps. Concept is described in more details here and full paper is ...
4
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2answers
792 views

Maturity of Mapserver mapscript C# bindings?

I've been thinking about possibly porting an internal custom GIS application built on top of Python / PyQt / Mapscript / GDAL-OGR / PostGis to C#. I was wondering about the maturity of the C# ...
3
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1answer
568 views

With CTM how can I get the latitude and longitude bounding box of a geoPDF?

Embedded in a geoPDF is info on the CTM - Coordinate Transformation Matrix. I am unfamiliar with this CTM. I know how to use python-numpy. How (or is it even possible) for me to use the CTM ...
6
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1answer
999 views

Altering composer label items in QGIS with Python

I'm only new to QGIS and Python so this may exists already, and hopefully be easy to do. What I'm hoping to do sometime in the future is build a map book generator using QGIS as the base. In order ...
2
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2answers
885 views

Any python script to convert a geoPDF to a KML embedded with a jpg link?

I have many geoPDFs. I want to turn them into KMZ or KML+JPEG using a python script. Any suggestions? SEE CODE BELOW