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

learn more… | top users | synonyms

1
vote
0answers
20 views

Q: cursor memory and fields therein

Theoretical Python question. Say you have an update cursor while-loop for a few selected records. While looping through the rows, at some point a nested if statement triggers an "addfield" event. The ...
1
vote
0answers
245 views

Calculating area with python qgis

I am a little stumped with determining the area of polygons in the python console. I want the output to be in meters^2, so using: qgis.utils.iface.mapCanvas().setMapUnits(0) ...
1
vote
0answers
179 views

Editing of vector layer programmatically with QGIS

I'm trying to edit vector layer using Python console and have couple of questions. Why this approach doesn't work and I have to use canvas.refresh? If I will use this code not in python console but in ...
1
vote
0answers
175 views

Unable to render layers in MapCanvas using PyQGIS/PyQt4

I am trying to get some layers into a MapCanvas and style them. I am following the PyQgis Cookbook info here but my code is just not working. I've been spinning my wheels on this for over a week now ...
1
vote
0answers
143 views

Is it possible to get field type information from FieldInfo object in ArcPy?

I'm looking at the FieldInfo object documentation for ArcGIS 10.2 and am not seeing access for field type (e.g. short, string, double). Is it possible to get field type information from the ...
1
vote
0answers
266 views

Locating the centroid (center of mass) of spherical polygons

I'm trying to work out how best to locate the centroid of an arbitrary shape draped over a unit sphere, with the input being ordered (clockwise or anti-cw) vertices for the shape boundary. The density ...
1
vote
0answers
69 views

Russian in fieldname changing with Python in ArcGIS

Is there any way to rename fieldname in the attribute table of a layer/shapefile in ArcGIS 10.2 containing russian letters? If yes, is it possible to do it in a script?
1
vote
0answers
68 views

How to create a startup prompt that populates definition queries on multiple feature classes

I would like to create an ArcGIS start up prompt or custom button that asks for a user's initials and then populates multiple feature class & layer definition queries. More specifically, I would ...
1
vote
0answers
68 views

Access to python addin objects/variables in python window

Following up on this question: Can a Python script be executed from a .NET AddIn and also write its standard output and geoprocessor messages to the ArcMap Python Window? Is is possible to access ...
1
vote
0answers
69 views

What is the best way to handle geometries between Python functions?

What is the best way to handle geometries between different Python functions? For example: I have a function that exports a line from grass.script. The line will be a parameter of another function ...
1
vote
0answers
157 views

GDAL and Python: How to “pad the extent” or otherwise handle band.ReadRaster() for area falling slightly outside the image bounds?

In a nutshell, I'm trying to create a bare-metal tiling utility using GDAL and Python. As you can see in the graphic below, which shows the perimeter of a raster and the OSM-structured tile index, ...
1
vote
0answers
186 views

Matplotlib Basemap Resolution with PyQt makes Python Quit Unexpectedly

I'm having difficulties using Matplotlibs Basemap in combination with a PyQt4 interface. Basically I create a Pyqt4 Canvas in which I plot a Matplotlib Basemap and some markers. I call the function in ...
1
vote
0answers
112 views

Efficient computation of path profile with Numpy and GDAL

I have numpy array with SRTM elevation data and I need calculate path profiles - vectors with elevation data from one point (transmitter) to every points of my map. Here's my current solution: def ...
1
vote
0answers
112 views

AttributeError: Error in getting tool information when using TableToTable tool

I am trying to use the arcpy.TableToTable_conversion tool in my python script, but seem to be getting the following error on the line arcpy.TableToTable_conversion("FINAL_NLPG", ...
1
vote
0answers
183 views

Composite bands produces a single band image

Running this produces a single band tif and not a three band image. Has anyone seen this before or can suggest ways to trouble shoot it? Input_Rasters = path + parentdir + "/" + dir + "/" + ...
1
vote
0answers
272 views

Couldn't load PyQGIS, QGIS 2.0.1 on Ubuntu 12.04 Precise

After upgrading to QGIS 2.0.1 I still get the error: Couldn't load PyQGIS. Python support will be disabled. Traceback (most recent call last): File "", line 1, in File ...
1
vote
0answers
68 views

Obtain virtual output directory path in geoprocessing service

I am publishing a geoprocessing service and I want to be able to access the virtual output directory path configured for the service. Now I know that gp services will magically return virtual paths ...
1
vote
0answers
93 views

How to join attributes by location with command line

I would like to joint the attributes of 2 shapefiles by location but with a command line (linux). This feature is easy in QGIS but it is VERY slow. Is there a way of doing this with ogr or pyqgis ? ...
1
vote
0answers
248 views

merge_management

Here is the edited code: import arcpy import os from arcpy import env set the environment settings env.workspace = "C:\RG\Kings County\Test.gdb" fcs = arcpy.ListFeatureClasses("Sub_NVF_*") ...
1
vote
0answers
256 views

Pyshp 1.2 example from documentation fails

I must be doing something really stupid because I am trying to run an example straight from the PyShp (shapefile.py) 1.2 documentation with the only change being the input shapefile and it is failing. ...
1
vote
0answers
167 views

Modifying Raster Layer with Python Console

Forgive me if this has been asked somewhere else. I am looking for a way to edit a raster file which has already been loaded into QGIS through the python console (i.e. I would like to edit the raster ...
1
vote
0answers
120 views

Reference to Basemap instance's coordinate system

I use the matplotlib basemap toolkit (mpl_basemap.Basemap) to plot GeoTIFF images on a map background using pcolor() or pcolormesh(). For this purpose, I need to transform a meshgrid of x and y ...
1
vote
0answers
77 views

How to create a schematic view of a line feature?

DEAR PEOPLE FROM THE FUTURE: Here's what we've figured out so far… I have a line feature (polyline with curves) in ArcGIS Desktop, and I want to create a linear representation (straigth line) of the ...
1
vote
0answers
146 views

How to use the QgsMapToolIdentify in PyQgis?

I'm trying to implement the QgsMapTollIdentify class in a stand alone app but I can not. I am a newbie in Pyqgis and would like to ask how do I implement this class in Python? Thanks! Completing, ...
1
vote
0answers
48 views

Qgis 1.9 commitChanges() and Redraw a temporary layer

Using QGIS 1.9 and writing a python plugin. I have a function that connects points into polylines and draws them as a temporary, in memory layer. Membership in a polyline is determined by a field in ...
1
vote
0answers
234 views

Calculating the closest distance between two points in ArcMap 10.2

I am looking for a script to calculate the closest meter to a set of addresses. I have a feature class of meters and a feature class of addresses. I have populated the address with fields for ...
1
vote
0answers
97 views

Automated attribute update geometric network

I have a Network Dataset of a storm water system containing two feature classes of points and lines. (All data is topologically sound with pits and pipes snapped and linework captured in direction of ...
1
vote
0answers
102 views

How to rotate u and v components of wind in rotated gribs?

I have a grib message of a rotated hirlam product. The grib message states, that the u and v component contained are relative to the rotated grid. How can I unrotate them?
1
vote
0answers
178 views

proj/pyproj converted coordinates offset

I'm using pyproj to convert some coordinates from WGS84 to OSGB36. When mapped out the converted and unconverted don't map to the same places on a map. The OSGB36 coordinates are mapped about 100 ...
1
vote
0answers
51 views

Deleting network features in python script doesn't create net junctions

I have a script that makes a copy of a network dataset for a 3rd party app to use. One of the junction feature classes causes problems with the app. The ideal solution would be to remove it from the ...
1
vote
0answers
166 views

Can ModelBuilder be used to export different versions of the same mxd with various constraints?

I am currently trying to use modelbuilder to go through each row in an attribute table, select the streets that intersect the polygon (which is the row in the attribute table), zoom to the selected ...
1
vote
0answers
310 views

Loop though records in PostGIS (using PL/PYTHON or PGSQL)

I've seen many example of loops, but I can't get that one to work. I work for a regional transit agency and each year, we conduct several surveys. I geocode everything to the house level for internal ...
1
vote
0answers
102 views

how to avoid Intersection of polygons via python code

i am using QGIS 1.8 and i can set the check box in Setting\Snapping Options "Snapping and Digitizing " dialog to avoid polygon intersections and enable topological editing but i am looking for a way ...
1
vote
0answers
312 views

Why does ArcGIS Resample tool change cell size and numbers of columns and rows?

I am working with images of oxygen distribution within individual plant root systems submerged in water. The program I use to acquire these images, LookatRGB, splits the green band in half and makes ...
1
vote
0answers
225 views

problem with WFS Data, GDAL, Python, ArcGIS, & Defining Projection

I'm pulling in data in gml2 format with a EPSG#4267 from a wfs. I create a datastream in python and then run the following from the python window in ArcMap: data = datastream.read() #write the gml ...
1
vote
0answers
131 views

How to shift vertices of shapes in shapefile using FOSS python library?

I need to shift each vertice of shape in a shapefile (of any type:point, line, polygon, multiline etc.) with Python. I need to loop in all shapes, get the vertices, get it's coordinates and for each ...
1
vote
0answers
255 views

XY event source layer problem (converts into feature class after running python script ) in ArcMap 10.1

I am using ESRI 10.1 suit (ArcGIS Desktop & ArcGIS Server, No ArcSDE) at my end and after running python script n number of times event layer converts into feature class. Following steps I am ...
1
vote
0answers
247 views

Qgis libqgispython.so failed to load

I am using Qgis 1.8 and Python (on Ubuntu 12.10) for a couple of month now, but today i got suddenly the error Couldn't load Python support library: Cannot load library /usr/lib/qgispython: ...
1
vote
0answers
163 views

How to create multi-image single band single file geotiff?

I have a geotiff file that is single band but contains multiple subdatasets. I use gdal with numpy to open a specific subdataset and mask some of its values. Example: $ gdalinfo sample.tif ... ...
1
vote
0answers
59 views

QGIS Gazetteer Plugin connection to internal database

A few posts on here mention that the Astun QGIS-Gazetteer-Plugin could be adapted to reference a PostGIS database. Has anyone done this adaptation and could share it? I want to use a gazetteer stored ...
1
vote
0answers
238 views

Add metadata to dataset (feature class, coverage or shapefile) from a .csv using arcpy?

I am looking for a script that will take metadata information provided in an excel table, convert it to a .csv and import the values to populate some of the dataset's ArcGIS metadata elements. I came ...
1
vote
0answers
112 views

QGIS GPS bluetooth connection

I have setup a Haicom bluetooth gps on a machine running Windows8 and have used GPSGate to create some virtual COM ports. I have valid data arriving at the COM port, but then I run QGIS and try to ...
1
vote
0answers
37 views

Problem in analyzing data in a stream segment

I have to find out the head difference along the stream segment. For that I used Spatial Analyst Tool>Extraction>Sample. With that I got the elevation values in points. But after doing so, i found ...
1
vote
0answers
58 views

Ubuntu Raring - Openlayers Plugin 1.8 or 1.9 Master

Relative newbie to Ubuntu and QGIS. Many questions are posted relating to the Openlayers plugin. It works fine in windows but I cannot get it to work or even appear in either 1.8 or 1.9. The "fetch ...
1
vote
0answers
155 views

Python Script Producing Empty Cost Path Rasters

I'm trying to run a script that will create cost paths for a large number of randomly generated points then assign the cost to those points. But my script is beginning to create cost path rasters ...
1
vote
0answers
331 views

Install shapely for QGIS on Mac

I know there are a number of similar questions, but none of them have answers that allow me to use shapely in QGIS. In particular I am trying to install the Contour plugin, but this fails with the ...
1
vote
0answers
105 views

Subset a GeoTIFF image into regular grids and extract mean latitude, mean longitude, and mean RGB for each grid

How can I subset a GeoTIFF image with 1000 by 1000 pixels into regular square grids of 50 by 50 pixels (400 grid objects in total); and calculate mean latitude, mean longitude, and mean RGB for each ...
1
vote
0answers
389 views

Why does XYToLine_management give ExecuteError ERROR 999999 The table was not found?

I've written this script to import a csv file using ArcGIS' flavor of python.. ArcPy.. It seems to run fine up until the XYtoLine tool runs and then it fails.. This is the error message... Traceback ...
1
vote
0answers
208 views

SEXTANTE runalg and QgsVectorLayer issue

I'm trying to make a script for converting polygons to lines. But I'm having some issues while generating temporary layers. In this script, I iterate through all the features of the input layer to ...
1
vote
0answers
358 views

Python Addin toolbar- Environment mask parameter not being recognised?

I've created a button on a python addin toolbar which uses the selected features from the selected layer in the TOC, creates a feature layer from that selection and uses that feature layer to set the ...