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

learn more… | top users | synonyms

0
votes
1answer
100 views

Make many lines in one layer (Python)

I what to create many lines with this code: v_layer = QgsVectorLayer("LineString", "cable", "memory") pr = v_layer.dataProvider() seg = QgsFeature() seg.setGeometry(QgsGeometry.fromPolyline([...
8
votes
1answer
354 views

Difference between python window and toolbox

Are there differences in performance or other potentially critical area between running a python script in the python window versus running it from the toolbox in ArcGIS 10.0? I am asking in cases ...
5
votes
1answer
2k views

Python - OGR: Transform coordinates from meter to decimal degrees

I have a point in a shapefile. The shapefile is in a WGS_1984_Web_Mercator Projected Coordinate System. I want to get the coordinates of that point in decimal degrees with GDAL/OGR in Python. I am ...
0
votes
2answers
90 views

Python to get ids from shp dont return all records

I have some Python code to get the ids and georeference from a shapefile: canvas = qgis.utils.iface.mapCanvas() allLayers = canvas.layers() nos = QgsFeature() for i in allLayers: if i.name()=='...
0
votes
1answer
117 views

How to convert geometry of SHP to decimals

I try to create a line with two points. These points are obtained in a SHP layer. How can i convert that points to decimals? Thank you
13
votes
1answer
532 views

Watermarking photos using their geotag and create a shapefile

I have geotagged photographs and I would like to place a watermark of the photos location on the front for easy reference as well as creating a shapefile from the coordinates. Does anyone know of any ...
0
votes
0answers
316 views

python script to calculate and return values based on several conditions

I need to calculate and return the value "continuous" to those records in a polygon feature class with species records aggregated to a UTM grid considering the attributes are species name, grid code, ...
4
votes
1answer
3k views

How to use CURRENT map document in Python tool?

I am attempting to use this code in a tool that I am working on: mxd = arcpy.mapping.MapDocument("CURRENT") df = arcpy.mapping.ListDataFrames(mxd)[0] XMIN = df.extent.XMin YMIN = df.extent.YMin XMAX =...
0
votes
0answers
38 views

How to get Perpendicular cross section along the river using python and Arc Map 10? [duplicate]

I need to draw the perpendicular line segment along the river at a regular interval. How can i obtain like this output using Python and Arc Map 10 ? I would be very grateful if you give some idea..
4
votes
2answers
702 views

Python split table by “State” field and export to individual tables?

So I have never posted here before. I have used the site a lot for help so many thanks to all the great contributors. So, I have used ArcGIS online to perform batch geocoding (18,000) records and it ...
0
votes
1answer
353 views

QGIS Python - Convert geometry from Postgres to QgsPoint()

I have made a query in Postgres to get some points to use with python. This points are in geometry data. How can I convert that geometry in decimals to use QgsPoint() in python? Thank you
-1
votes
1answer
2k views

How can i draw a perpendicular line in a stream segment in a regular interval of 30m? [duplicate]

I have a stream segment which is polyline feature. Now I want to draw a line which is perpendicular to stream segment at a interval of 30m. How can i do it using python ? Do you have idea on this .
1
vote
1answer
379 views

Can I open a form in layer action?

I want to open a form (made in QTDesign) in the layer action. It is possible?
5
votes
2answers
464 views

Accessing arcpy functions from IronPython

I made a few python scripts to automatically optimize and publish my data.. Now i'm thinking about writing a .NET program to manage and run these scripts: the obvious way is invoking them in a ...
0
votes
1answer
2k views

How to insert values from one table into another?

I am trying to write a script that iterates through each row of a table, calculates for this row something. The result of this calculation is finally stored in another table (with just one row). Now I ...
0
votes
0answers
18 views

QGis non blocking notifications with pyqgis [duplicate]

I'm searching for the way to use the new QGis non blocking notification system with the QGis python wrapper. I found informations on this fonctionnality but nothing on how to use this especially with ...
3
votes
2answers
425 views

Tabulate Area crashes Python and ArcGIS

I have a script that runs Tabulate Area on a single feature class multiple times with different rasters. In total Tabulate Area runs 5 times. 2 of the input rasters are provided as arguments to the ...
2
votes
1answer
468 views

Arcpy Network Analyst solver error

Hello GIS Stack Exchange, I am finding it difficult to load locations to sublayers using python in ArcGIS 10.0 network analyst Vehicle routing problem. I'm also having some trouble debugging my ...
0
votes
0answers
31 views

using python and arcpy , how can I compute the direction and angle of a line segment? [duplicate]

if start_point_x < end_point_x and start_point_y > end_point_y: slope = ((end_point_y - start_point_y)/(end_point_x - start_point_x)) radian = math.atan(slope) degrees = math.degrees(...
1
vote
0answers
610 views

Calculating the Centroid of polygon in modelbuilder (VBA to Python) [closed]

Got an easy one, that's got me stuck. I'm moving some models that were created in 9.3.1 to work in 10. Part of the model is calculating the X coordinate of a polygon to a specified field. The code ...
0
votes
1answer
428 views

arcpy.setValue for Condition from Dictionary

Hi: I am trying to create a function to update multiple fields based on different criteria. I want to pass the field name and condition thru' a dictionary (please see the function description in the ...
1
vote
1answer
292 views

Python GDAL: find out spikes and pits in DEM

I'm working with on a DEM (Geotiff) in Python GDAL, and I'd like to find out the spikes or pits in my terrain. I have no idea how to proceed, does anyone have good algorithm to help me out? Thanks, eo
1
vote
2answers
285 views

Set Extents of MXD to new layer data source?

Alright here I go again this forum has been good to me. I add a layer and replace its data with a shapefile I created using the following bit of python: layer = arcpy.mapping.Layer("C:/GIS/images.lyr"...
0
votes
3answers
5k views

Create Text files from a loop with Python? [closed]

I need to create some files to hyperlink to from Arcmap. I have a folder of jpeg files (100.jpg, 101.jpg etc...). I need to loop through them and create a text file of the same name except replace the ...
1
vote
2answers
572 views

ArcGIS 10.1: “ERROR 000223: Cannot extract event table properties” when iterating through multiple files/folder

I am trying to convert ~270k csv-files with lat/long-data to layerfiles. The files are split into folders by year, i.e. ~30 folders with ~9k csv-files in each. I have written a script to iterate ...
3
votes
2answers
1k views

Field calculator or update cursor?

I have a feature class in which one field (let's call it "Field_A"), as yet empty, is to be populated by the contents of another field ("Field_B") multiplied by a certain number (I'll call it the "...
1
vote
0answers
144 views

Python GDAL/OGR: check lines geometries connectivity

I'm working with shapefiles representing roads, so basically it's stored as (poly)lines. I need to perform a road connectivity checking. In other words, I want to ensure that roads meant to ...
1
vote
1answer
2k views

Make Route with Python and network analyst in ArcGIS 10

Good Day, I'm having trouble debugging my python code to create a network analyst layer in ArcGIS 10.0. Basically when run from a script tool the code completes successfully without actually doing ...
3
votes
3answers
2k views

Batch clipping rasters in QGIS?

I have been able to batch clip rasters in one directory using python in ArcGIS. However, I am not sure how to do the same in QGIS using the Python console. Is this possible?
1
vote
1answer
625 views

spatialite.dll with Python and QGIS - the specified module could not be found

I'm having a bit of a nightmare getting to the bottom of this DLL loading problem. The stand alone script works absolutely fine but the exact same code does not work within QGIS. import sys from ...
2
votes
1answer
232 views

Python script to update attributes crashing during loop

I have a script to update a field in one feature class from a selected record in another feature class. This is done through looping through records in one feature class selecting appropriate the ...
0
votes
1answer
361 views

How to access the button on the form?

I have a form that appears when you start the plugin.How do I properly apply to the button on the form, so that when you click on the button performed "function". import sys,os import win32api from ...
0
votes
0answers
52 views

How specify a corridor minwidth?

I’m trying to make a corridor between two substations with ArcGIS, a macro corridor and a micro corridor. I have two questions in this respect and would be grateful for your suggestions. a) How can ...
1
vote
1answer
264 views

How to add attributes to shapefile with Python and pyshp?

I'm using pyshp for creating a shapefile. I need to populate tens of fields with values using the record() method of shapefile.Writer. I have those values as a list, but have no idea how to send it to ...
0
votes
0answers
78 views

Congressional Redistricting

I have a project coming up where I need to create new congressional district looking at only total population data. I am planning on using the census tract level of data, but I am having some ...
12
votes
1answer
7k views

GDAL/Python: How do I get coordinate system name from SpatialReference?

In Python, using GDAL, I've extracted a raster's projection as a WKT string as follows: wkt = dataset.GetProjection() # wkt is 'PROJCS["GDA_1994_Transverse_Mercator",GEOGCS["GDA_1994",DATUM["GDA_1994"...
1
vote
1answer
152 views

Setting More Than One Workspace

I have a number of tables that contain known values in a field. For example, I have a soil type table with one field in it. That field contains a list of known soil types. I have another table that ...
1
vote
1answer
90 views

ArcGIS 9.3 geoprocessing service output consideration

I'm developing geoprocessing service which do few processes with geographic data. I would like to get somehow geometry of those data and use it in my web aplication (JS ArcGIS API). Now I'm wondering ...
1
vote
1answer
217 views

Need python code example - setting a combo listbox to Null

I want to be able to set the value of a field to Null using python, but I get an error. I am using arcpy.CalculateField_management
0
votes
2answers
982 views

Tile script (Mapnik) with OpenLayers - Problem with projection (900913)

I use Mapnik python bindings in a geodjango application to render tiles in openlayers with datasource stored in postGIS in 900913 projection. The feature seems to be rendered correctly in the ...
2
votes
1answer
2k views

How can I create a line with three points with Python in QGIS?

I'm new to Python and I'm having some dificulties. I want to create a simple layer with a line in the console of QGIS with Python. How can I do that?
0
votes
1answer
858 views

Check if layer is a QGSVectorLayer from Python Plugin within QGIS

I am trying to extend some concepts in the QGIS Workshop tutorial. Basically, I would like to check if the layer is of type "QGSVectorLayer". In the QGIS Python console, I am able to type canvas = ...
2
votes
1answer
612 views

Generate unique ID upon creating a feature?

Looking for a way to generate a unique Global ID within a feature set when a new feature is created. For example, every time a sewer manhole is added, we need to generate a new unique Global ID that ...
2
votes
1answer
369 views

python gdal_polygonize error

I am trying to use gdal_polygonize to create a polygon from a binary raster. My code is: os.system('gdal_polygonize.py ' + filename + ' -f ESRI Shapefile ' + shapefile) where filename is a string ...
2
votes
1answer
192 views

OGR UnionCascaded gives strange lines (flat polygons)

I'm using OGR to perform a union using UnionCascaded. All my polygons have been created by GDAL polygonize which ensures that all polygons follow pixel edges and should therefore align nicely. But I ...
5
votes
4answers
890 views

How to computational efficiently check if there are any overlapping polygons in a group of polygons?

I need to do some processing with groups of polygons. If any of the polygons in the group overlaps other polygon the result is unpredictable and don't throw any error. So, I need to detect if there is ...
1
vote
2answers
3k views

ArcMap label expressions with Python

Having trouble here: I'm trying to use python to write selective label expressions. I have several concentrations and depending on its "_Ex" number I either want it labeled red, not red, or not ...
-1
votes
1answer
539 views

QGIS and Python - create line with multiple points in postgis [closed]

How can I create a line, with Python functions, with many points that are records in Postgis? Thank you
7
votes
3answers
3k views

How to Refresh open attribute table in ArcMap using ArcPy rather than ArcObjects?

I am running the Calculate Field GP tool from the arcpy in ArcMap. When a row value is updated, it does not show up untill I use the Reload Cache tool (Table Options > Reload Cache). How do I refresh ...
2
votes
1answer
367 views

Search cursor stops selecting after two iterations

I have a script which selects an extent from a grid and exports the data frame. import os, arcpy mxd = arcpy.mapping.MapDocument('CURRENT') df = arcpy.mapping.ListDataFrames(mxd,"Layers")[0] ...