Python is an open source interpreted programming language used in many GIS programs.
6
votes
6answers
7k views
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 ...
6
votes
2answers
4k views
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 ...
6
votes
4answers
1k views
Raster to Polygon Scripting Problems
I am trying to make a script which selects every .png file in a folder beginning with the letters "LG". I then want the scipt create a shapefile, replacing the "LG" with "SH", and then i want the ...
6
votes
2answers
2k views
Basic Field Calculator Python Question
I'm trying to used the Python syntax in ArcGIS 10's field calculator and am thoroughly confused. So far the most basic calculations are failing me, and I don't understand why.
I'm trying to create a ...
6
votes
4answers
2k views
Compiling Python Scripts That Use ArcGIS Geoprocessing Tools
I've been coding with Python for several months now and have developed some reasonably complex scripts for primarily geoprocessing tasks. That being said, I'm still learning a lot as I'm coming from a ...
6
votes
2answers
413 views
Can I get a list of my selected features in ArcGIS by using Python code?
I have a question regarding selections in ArcGIS. Assumed I have one layer in ArcMap and I have selected two of five features. Is it possible to get a list of all selected features by using Python? It ...
6
votes
2answers
733 views
Creating geodatabase from CSV using python
I have a file with weather data (daily) for multiple weather stations for multiple years. I am looking for some python script to automate the database creation process and its interpolation on a daily ...
6
votes
4answers
2k views
Field Calculation - Python - If/Then over multiple data columns
I have some VB code saved that looks at two columns of data, and populates a third with the low value.
Pre-logic Script Code:
Dim output as double
if [MIN_LEFT] < [MIN_RIGHT] Then
output = ...
6
votes
2answers
165 views
Python scripting- compute statistics
I'm new to Python but I've heard is a good way to automate tasks. I have thousands of point shapefiles and need to extract the maximum value of each one and put them in a new table. I'll appreciate ...
6
votes
3answers
653 views
Why is an extra field necessary when creating point shapefile from csv files in Python?
I have a Python script that creates a point shapefile from a csv file within a Python script. This script gives me a ValueError for the longitude field (LON) if there isn't an extra nonsensical field ...
6
votes
2answers
2k 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 ...
6
votes
3answers
3k views
Arcmap: attach python script to a button?
In ArcMap 9.x how can I attach a python script to a button?
6
votes
5answers
1k views
How to convert line simple features to topological network?
using Gdal/ OGR is there a way to convert a shp, kml, or PostGIS line layer into a network of nodes and segments so it can be used in packages such as networkx?
6
votes
1answer
96 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 ...
6
votes
3answers
217 views
Classifying point coordinates to countries or continents?
I have about 50 000 points (latitude and longitude), and I would like to find out in which country each of the points is located. It does not need to be super precise, though.
(Or actually I only ...
6
votes
2answers
189 views
projection tool as standalone script
How would I automate the define projection tool in arcmap so I can just enter my layer each time? I have it as a script in toolbox, but I am unsure how to set it so I can just input my layer as ...
6
votes
3answers
2k views
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
...
6
votes
3answers
3k views
Using model builder, how can I extract certain fields for 1 selected feature from a point shapefile file with multiple features?
I have a point shapefile that is filled with many features. If I have 1 feature selected I need to be able to export certain fields of that selected feature (ID, lat, long) into a dbf file. What ...
6
votes
2answers
2k 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 ...
6
votes
3answers
271 views
How to extract area programmatically?
is there a possibility to extract the area covered by one geometry of a shapefile (polygon)?
I tried with
thepoly.area()
but get "nan" as result.
Ok. I think you are right and there is ...
6
votes
3answers
218 views
Using ESRI geoprocessing services from a non-ESRI client (Python)?
I'm thinking it should be possible to consume an ESRI Geoprocessing service from a python script without invoking ArcPy or needing an ESRI installation on the client machine. For example I create a ...
6
votes
3answers
133 views
Zero filling attributes using python
Being the AML dinosaur that I am, I am just learning python and I need to convert a 2 digit numeric attribute in a table to a 2 digit zero-filled attribute in a script. Example 9 needs to be 09. Any ...
6
votes
1answer
319 views
How to add a toolbar via python?
Through tutorials I learned how to add a toolbutton to the plugins-toolbar via python. Now I wonder how to add a complete toolbar with toolbarbuttons via python.
Can anybody give some example-code?
...
6
votes
4answers
1k views
Efficient arcpy method of points in polygon
Coming from a background of Mapinfo and Manifold, I frequently find myself frustrated with the ArcGIS SQL toolset. In both these former programs it is trivial to write a query asking, for instance, ...
6
votes
2answers
721 views
Process a raster with multiple geoprocessing tools in arcgis 10 using python - flow between processes
I'm writing a short python script that includes processing rasters with different geoprocessing tools in ArcGis 10, for example, the three processes below, is this best way to use multiple tools ...
6
votes
1answer
116 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!
...
6
votes
2answers
185 views
ArcGIS 10.1 Python Addins - Am I doing this right?
I have been developing a few python addins and I'm just wondering what is the best way to re-compile the addin anytime I edit the script.
Currently, if I make an edit to the script, it seems like I ...
6
votes
2answers
738 views
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 ...
6
votes
1answer
337 views
Counting Files with a Spatial Reference using Python
I need to display a list of feature classes with an unknown spatial reference, and the number of feature classes with a spatial reference. I think I have the first part right, but having troubles with ...
6
votes
1answer
524 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)
...
6
votes
2answers
616 views
ArcGIS Python Tool Script Parameter - Binding Objects to a List Parameter
I am working on a python based script/tool. I would like to make use of drop down lists for several of the parameters. This is very easy to do if the lists are just plain old strings.
Does anyone ...
6
votes
1answer
149 views
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 ...
6
votes
2answers
213 views
Converting KML files for use with Python library Shapely
I am trying to get a KML-file (wijken.kml) into Shapely. The KML-file is validated against the proper XML schema, so I guess the input is correct.
Routes I have tried:
1) Converting to WKT or WKB ...
6
votes
1answer
299 views
concurrent use of in_memory workspace in arcpy
i am using a python script that's eliminating small polygons from a feature class. this script creates temporary feature classes with fixed (hardcoded) names in the "in_memory" workspace. example:
...
6
votes
1answer
985 views
How to convert Shapefile geometries to WKB using OGR?
I got the geometry of a feature of the shapefile, and i want to save that geometry in the postgis (in WKB formats like it happens when we import shapefiles using shp2pgsql and psql commands). How do I ...
6
votes
1answer
638 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 ...
6
votes
1answer
233 views
Does Arcpy work for Engine or Server the same as Desktop?
I am contemplating a project where there is not going to be access to ArcGIS Desktop and wondering if Engine and/or Server install ArcPy and Python? Is this possible? Does anyone have an example?
6
votes
2answers
964 views
Change from layout view to data view using python? (ArcMap 10)
Is there a way to change from layout view to data view using python? I would prefer to do it using arcpy.
6
votes
1answer
513 views
How to read/write from/to QGIS project file using Python?
I'd like to save the project-dependent configuration of my Python plugin inside the QGIS project file. Is this possible and what are best practices to do so?
6
votes
3answers
109 views
How to efficiently read and reclassify many rasters in R
I've been tasked to create a suitability analysis of wave conditions in the Gulf of Mexico. I have 2 thousand or so raster files that are about 8 MB each (2438 columns, 1749 rows, 1km cell size). ...
6
votes
2answers
139 views
How to parse serial date in ArcGIS?
I have imported a shapefile that contains a serial date number that looks like this: 41256.260799. I would like to create a new field that shows only the hour and second like this: 06:33. I've tried ...
6
votes
2answers
121 views
How can I turn a vector layer into a graph G = (V, E)?
I have a number of rail networks, in the form of shapefiles of the "line" type. I want to turn them into a more abstract graph format, i.e. the kind with vertices and edges, not chart-type graphs. ...
6
votes
1answer
600 views
Python script to convert Lat Long to ITM (Irish Transverse Mercator)
I am currently working on a python script that converts Lat Long (WGS84) to ITM. The formulas used are based on a paper published by OSGB (Appendix B):
...
6
votes
2answers
566 views
Calculating Field based on name of shapefile
I have multiple shapefiles to which I have added a field called "gname1". For each shapefile, I want "gname1" to be set to the name of that particular shapefile, for every feature within the ...
6
votes
3answers
749 views
Raster: How to get elevation at lat/long using python?
I was wondering if anyone has some experience in getting elevation data from a raster without using ArcGIS, but rather get the information as a python list or dict?
I get my XY data as a list of ...
6
votes
1answer
224 views
Use Python to find the pathname of “Current” Arcmap
I am trying to find the path name of the current ArcMap document that the python script is currently running in.
For Example:
"F:\2012\1111\MyArcMap.mxd"
I tired using
sys.argv[0]
as shown ...
6
votes
1answer
437 views
Is there a way to access QGIS plugins in Python?
Is there a way to access QGIS plugins in Python? I'd like to write a script to do some geoprocessing, and I'd like to use the clip, regular points and convex hull tools in fTools, as well as the Road ...
6
votes
1answer
757 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 = ...
6
votes
3answers
2k views
Convert .mxd with embedded VBA command button to ArcMap 10
I'm trying to convert an .mxd file from an older version to ArcMap 10. The old version had two simple VBA scripts attached to toolbar buttons. I am trying to convert this .mxd to ArcMap 10. For ...
6
votes
1answer
682 views
How to toggle layer visibility in QGIS using Python?
How can I toggle layer visibility in QGIS via Python API?
