Tagged Questions

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

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1
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0answers
23 views

cadtool and spline plugins not working

Am trying to edit a line shapefile using a spline tool in QGIS 2.4.0 .Its drawing but the ok button is inactive. what could be the problem? Generally am trying to create a curved line.
1
vote
2answers
80 views

Vertical lines in a polygon shapefile

I am working with a GIS problem using a single input of a polygon shapefile. Consider an irregular polygon. I want to draw vertical lines across the extent of the polygon at equal spacing. How I ...
1
vote
2answers
58 views

How to concatenate double with string in field calculator with Python expression?

I'd like to concatenate my lat/lng with a few string fields in ArcGIS. What is the correct expression to use, avoiding VBA. I don't want to convert the lat/lng fields to string either. my 4 fields ...
1
vote
0answers
18 views

Python Script calling custom model failing during model execution

I have a python script that calls a model I built in model builder. If I run the model by itself it runs perfectly. If I call the model in the python script, the model errors in various locations. ...
0
votes
1answer
163 views

'List indices must be integers not tuple' Error

I'm using an insert cursor to write rows to a destination feature class where the input Shapefile field names do not match the destination FC names. To accomplish this, I'm trying to use the indices ...
1
vote
1answer
45 views

Load feature class with tab delimited file that is missing Lat/Long

I am working on a Python script that receives a nightly tab delimited flat file. This flat file has Latitude and Longitude fields and the script loads the data using the gp tools Make XY Event Layer ...
12
votes
5answers
2k views

Python is only using one core at a time to work

I noticed recently that python is only using one core at a time to work. Is there a way, maybe special builds or commands, to make it use all resources (second core)?
1
vote
1answer
51 views

How to properly import QImage from PyQt4.QtGui?

I am starting with QGIS python console. Naturally, I came across the PyQGIS Developer Cookbook. While trying to cut my way through it, I encountered a lot of problems with "undefined attributes and ...
1
vote
2answers
84 views

Error "unsupported operand type(s) for +: 'int' and 'NoneType' for variance in python

I recently came up with an error in a script I am working with in Python for ArcGIS 10.1. The strange thing about it is that this script works for some files and not for others. Any ideas as to why ...
4
votes
2answers
65 views

How to programmatically delete all inner rings of a polygon layer?

I have many polygon layers, each layer containing many polygons with inner rings. I know that you can delete a ring manually with QGis (Edit -> Delete ring). I need the python equivalent to ...
1
vote
0answers
33 views

Orthographic projection in Python Basemap

I'm trying to plot a GeoTIFF in Python using Basemap. I can do so correctly with cyl projection like this: m = Basemap(projection='cyl', llcrnrlat=LL[1], urcrnrlat=UR[1], ...
2
votes
2answers
126 views

Join Field works in ArcMap but not in Python

I am trying to join a field of values found within a DBF to a multi-polyline shapefile. They share a common field name (filename) and the values found within each are identical. I was able to run Join ...
3
votes
2answers
67 views

Script for numbering roads based on Cardinal Direction

I am kind of new to python, and am attempting to write a script that will give me a unique identifier for roads based on the cardinal direction. Ultimatley, I would like to have a system set up such ...
2
votes
1answer
59 views

How to detetmine county of GPS coordinate?

I have a SHP file that contains all counties in the USA. I also have roughly 100 million GPS locations. I need to tally the number of GPS locations per county. A linear search through the counties ...
2
votes
0answers
52 views

Run a large model by calling it in a python script?

I've created a rather large model containing a sub-model that calculates the volume of water basins(playas) in a relatively flat area of Texas. The volume is taken from one foot slices of each each ...
1
vote
1answer
92 views

List layer names from Map service using python

I am trying to get a list of layer names within our rest services for all services and folders. I have two codes that I am trying to put together and for some reason the layer code doesn't seen to ...
5
votes
1answer
111 views

Is it possible to drive one mxd (pan) using a different mxd with python?

I have 2 mxd's. mxdA and mxdB They both show different data, but are both in the same coordinate system. I want to be able to sync mxdB with mxdA, so that if I pan / zoom in mxdA, I can then, with ...
3
votes
0answers
60 views

Problem with performance when loading PostGIS layer using pyQGIS

I'm having a question on loading a PostGIS layer into the project from my QGIS plugin. The code is like this: uri1 = qgis.core.QgsDataSourceURI() uri1.setConnection(str(host), str(port), ...
2
votes
0answers
23 views

Run an ERDAS Imagine pmdl (or bcf) via Python?

How (or is it) possible to run an Erdas Imagine .pmdl model from a Python script? I have successfully run .eml models but cannot get the syntax right for .pmdl Here is what the line I want to run ...
2
votes
1answer
50 views

Python loop with address locator

I was given a list of addresses without any zip codes, and I'm trying to write a python snippet that will loop through a set of possible zip codes and make a set of geocoded shapefiles that I will ...
1
vote
1answer
82 views

Using GDAL to read dted files

How do I get the elevation at a certain point using gdal to read in a dted file? I don't see much useful information out on the web. I'm sorry I should have been more specific. How would I ...
4
votes
3answers
134 views

How to get a list of attributes in FME when there are no records in table?

How to get a list of attributes in FME when there are no records in the table? I try use a PythonCaller but when there are no records, FME passes over this table. In PythonCaller I write: import ...
0
votes
1answer
50 views

Create Georeferenced Raster For JPEG file with Mapnik Python

I am able to use Mapnik generate_image.py to generate image with a BBOX and projection. Also, I have added a python script to generate a JGW file. But to completely georeference the generated image. ...
1
vote
1answer
47 views

Error on FeatureClass To FeatureClass conversion arcpy

I am currently working on a python script where I am trying to copy selected features into a feature dataset. Basically I have an mxd containing some layers, and for each layer I select features by ...
3
votes
1answer
127 views

Why is this field calculator expression evaluated incorrectly when using Python syntax?

I have a polygon featureclass containing an integer field 'gridcode'. I've added 2 new float fields VB_calc and Python_calc, both of which should be equal to gridcode / 1,000,000. If I calculate the ...
1
vote
1answer
123 views

Installing Pandas in ArcGIS 10.2 for Desktop?

I followed the very clear directions in the answer to Installing pandas with Esri's python? and created the Esri101 build and added a "conda.pth" file to my ...
1
vote
0answers
34 views

How to write in only a file .csv (or .txt) the values contained in several rasters?

I am an beginner in Python programming but I would like to write in only a file .csv (or .txt) the values contained in several rasters. For example, I built several rasters by using a loop. The ...
1
vote
1answer
31 views

Point input for polyline not acceptable?

Input QgsPoint(s) are returning an error in a Polyline creation routine. Any clues?! processing.runandload("qgis:polygoncentroids", Base, "memory:CenterNode") ...
1
vote
0answers
29 views

GeoDjango WebMapping Application Update

According to the below GIS.SE questions, GeoDjango was the preferred framework for creating simple and quick webmap applications. But these questions are now all 2-3 years old. Can we verify whether ...
1
vote
1answer
67 views

How to delete features/records in ArcGIS Server using Python

How can I use python to delete records from a table, or features from a featureclass, when they are stored in ArcGIS Server? using REST "delete features" in arcgis api for javascript shows ...
1
vote
1answer
54 views

Extract Values to Points between rasters and point shapefiles of the same name

I have a task of extracting raster values to point shapefiles, which is simple enough, but only where the raster filename is identical to the shapefile. For example, I have shapefiles "G1", "G2", ...
1
vote
0answers
45 views

How to load style from postgresql?

Is there any way to load a postgresql style for a vector layer using python? There is a function: loadNamedStyleFromDb (const QString &db, const QString &theURI, QString &qml).Does it ...
3
votes
1answer
45 views

Merging .dbf Tables in Python w/o merging all fields of same name

I'd like to merge several tables together using Python. They all have the same field names: "TIME", "X", "Y", and "VALUE". I would like the "VALUE" fields to remain separate when merged, so that the ...
1
vote
1answer
42 views

Problem with variable for arcpy.select_analysis whereclause

I have a problem with the whereclause on python for arcpy.Select_analysis. I try to use a variable for condition: for row_stat in rows_stat: % for calculated the variable"maxi" ...
2
votes
0answers
38 views

Python and gdalwarp: change resolution of raster

I am new to GDAL and have been having some hard time figuring out how to change a raster's resolution and how to align it to another existing raster. I have come to the point where I have a raster ...
1
vote
2answers
30 views

Parcel Map - How Many Acres of Feature X fall Within Each Parcel

Can someone recommend a good tool for ArcGIS that would help summarize how many acres of a polygon feature occur within each parcel in a separate layer. I have a layer containing a few hundred ...
3
votes
0answers
83 views

How to compute (X,Y,Z) of a point from given attributes

Is there a way to compute the geodetic coordinates (Earth Centered) of a satellite S(x,y,z). The original problem is to compute the footprint of an antenna, given the following information: ...
1
vote
0answers
20 views

Problem Loading Plug-Ins in QGIS 2.2 on Mac

I'm trying to load the 'processing' module in QGIS (2.2.0-Valmiera on Mac OSX 10.8). However, this module and others (e.g. GarminaCustomMap) re failing to load with a message: ImportError: No ...
0
votes
2answers
86 views

GDAL for Python: extracting subdomains from NetCDF file?

I need to make a script that processes a NetCDF file that contains 3 days of hourly forecast data from the norwegian meteorological office. The NetCDF file contains various data I need ...
3
votes
0answers
59 views

Create vector grid from canvas using script

I've modified "Hex grid from layer bounds" script to my need. Just added cellsizex and cellsizey. Changed the hexagonal - 3 to "1" to make it as a square grid. Is it possible to include an option to ...
1
vote
1answer
34 views

Standard SQL with ArcGIS

Is it possible to use Python to run actual standard SQL on an enterprise geo-database? Think about batch deleting, joints, etc moving beyond just the cursor objects in Arcpy. Note that one can ...
0
votes
1answer
23 views

Detecting Runtime Errors in Arcpy Loops [duplicate]

I am looping over a feature in Arcpy and doing several geoProcessing tasks on each feature/iteration. The loop runs pretty well but crashes on some of the features. I dont really know why but its ...
2
votes
1answer
67 views

Basin numbering according to Pfafstetter Method?

I would like to divide my basin into subbasins and numbers according to the Pfafstetter method. Is there an easy way to implement this in Python using ArcPy? Or are there some freely available ...
0
votes
0answers
52 views

ArcPy loops/cursors faster without background processing?

I am running loops via cursors and raw Python in Arcpy. Within the loop several processes take place, selecting shapefiles and converting to raster, clipping, running euclidean distances, extracting ...
5
votes
1answer
117 views

Pause ArcPy script until feature class lock goes away

My script needs to copy data into a feature class to an SDE geodatabase that might have a lock on it from another application. I shouldn't break the lock (that app has priority over a data update), ...
2
votes
2answers
62 views

Batch Conditional Test - For Loop with a Group of Rasters

Edit: Question was answered. Please scroll to see fixed script. Thank you everyone who helped! How do I ask a “for loop” to operate on groups of three files folder (e.x. files A, B, C), then files ...
1
vote
0answers
31 views

Mapping from one plane on the other plane despite of masking regions

have a set of data given here, where in the first and second columns there are the sky coordinates (ra,dec) e.g. right ascension and declination, respectively and in the third and forth, the ...
0
votes
1answer
65 views

Cannot load postgis layer from sql string in pyqgis

I'm trying to load a layer using the following code in qgis python console: sql = "(select the_geom, ID from mytable)" uri = QgsDataSourceURI() ...
1
vote
1answer
76 views

What's the reason for this Invalid Layer “Cannot open GDAL dataset …” error

When adding a rasterfile with QGIS python console there appears an error when the first letter of a rasterfile to be added is not written in capital letters. Why this behaviour? Example case1: ...
0
votes
1answer
56 views

D8 algorithm to get the flow direction in ArcGIS

I am using ArcGIS 10 for the get the flow direction from DEM. I wonder about the algorithm they have used while calculating flow direction. It is mentioned there that it is using D8 model. D8 model ...