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

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6
votes
2answers
559 views

Histogram Matching Python

I am trying to do histogram matching using Python to improve the mosaicking process of multiple overlapping rasters. I am basing my code on that found at: ...
1
vote
1answer
27 views

QGIS Plugins & Tools that replicate Select ArcPy Tools

I developed a complex python application for road generation from GPS Devices that uses a few Arcpy Tools. I want to try and replicate this Applications functionality using a freeware like PyQGIS ...
1
vote
2answers
33 views

QgisInterface.addVectorLayer Error

I am Esri-trained, trying to move into QGIS using Python. Simply trying to add a vector layer in Qgis returns the below error: TypeError: QgisInterface.addVectorLayer(QString, QString, QString): ...
3
votes
1answer
295 views

Putting coded domains into list to be created in Python script?

I have a large list of coded domains. They are numbers like: 01.6530.01, 05.7991.08, 05.7991.01, 05.7991.06 The code will be the exact same as the description. I've tried to make a list using: ...
1
vote
1answer
386 views

GDAL - How to get geometry type of a MapInfo TAB file?

I am using the OGR MapInfo File driver to read a MapInfo TAB file. However, the function GetGeomType() returns 0 which means 'wkbUnknown` even if the features in the TAB are only multi-polygons. Is ...
0
votes
1answer
33 views

Using If Statements in ArcGIS Calculate Field?

I've never used Python scripting before and can't seem to figure out how to use an If statement in the Field Calculator tool. I have a field called 'MAX_GRIDCODE' which returns the highest force a ...
3
votes
2answers
1k views

Moving cursor backward i.e. opposite of row = rows.next()?

Can anyone tell me if there is a way to go up one row in python cursor? i.e. opposite of row = rows.next()
3
votes
1answer
255 views

How to clip a Oracle query layer directly in a Python script?

I have a query layer directly running from ORACLE database in a MXD. I want to clip this layer with a layer being created in another MXD in a Python based tool. My question is to do this clip ...
1
vote
1answer
186 views

Running GRASS functions in QGIS 2.4 from python console

I am using qgis 2.4 and i am looking for the "easiest" way to execute e.g. the r.in.gdal function from the python console in qgis. Specifically for r.in.gdal, I could not found this function in ...
0
votes
0answers
10 views

Skipping the string serialization in json.loads(OGRGeometry::ExportToJson())

I have a for loop that exports a bunch of OGRGeometry objects to a python array in what will eventually become a GeoJSON feature collection. Something like this: features = [] for feature in ...
2
votes
1answer
40 views

different way to build qgis python standalone application

There seems to be 2 different ways to start a Python QGIS standalone script. The official tutorial is using : from qgis.core import * # supply path to where is your qgis installed ...
3
votes
2answers
360 views

Can I Dynamically Update Symbol Ranges?

Background: I'm currently trying to dynamically change the ranges for a layer with new style graduated symbology. Problem: I thought it may be as simple as updating the ranges for the existing ...
0
votes
1answer
49 views

Create a Loop for Arcpy

I am looking for help to write a loop a arcpy.CalculateField_maagement process where the User is asked with the 'raw_input', prior to the tool running "Do you need to change a field value(yes/no):", ...
2
votes
1answer
191 views

Import error when utilizing QGIS's Python Init function

Based on the answer to Referencing Qt UIs external to plugin with python. I'm trying to utilize the "Layer Properties / Fields / Python Init function" to execute a file (test_file.py) that is located ...
1
vote
1answer
29 views

How to restrict panning in QGIS to a given extent

I'm going to build a QGIS standalone application. According to the requirements full extent equals to the extent of a predefined rectangle (say bounding box of a parcel). The application should start ...
0
votes
0answers
11 views

GRASS 7 (python:14221): Gtk-CRITICA Linux Mint

I installed GRASS 7 and QGis from the https://launchpad.net/~ubuntugis/+archive/ubuntu/ubuntugis-unstable (Trusty 14.04) in Linux Mint 17.1 two weeks ago (sudo apt-get install postgis libgdal1h ...
0
votes
1answer
27 views

How to extract information from world file of images into a DBF catalog file through PYTHON?

Here are thousands of pictures in JPG or TIF format with world file such as jgw and tfw. Inside each file, projection information for each pictures were contained. One example of the content for a ...
1
vote
0answers
31 views

import qgis.core problem with QgsFeature and QgsGeometry ImportError: DLL load failed: The specified procedure could not be found

I've tried several previous answers to similar questions - no luck. I've tried everything, nothing seems to work. This is the error I'm getting Traceback (most recent call last): File ...
0
votes
2answers
165 views

SnapToCurrentLayer in QGis2.8 with python programming

I have a polygon vector layer and I want to snap the vertex. def canvasMoveEvent(self,event):   x = event.pos().x()   y = event.pos().y()   startingPoint = QPoint(x,y) ...
2
votes
2answers
166 views

Debugging ArcPy ImportToolBox AttributeError: Object: Tool or environment <ConcatenateRowValues_AA> not found?

I am trying to use the ConcatenateRowValues tool provided by ESRI. My overall code for my script is working fine except when it tries to use the ConcantenateRowValues Tool. I start by importing the ...
2
votes
1answer
165 views

Python Error while installing Cartogram

I am quite new to GIS and qGIS especially. I would like to install cfarmers cartogram plugin. From what I understand, this has to be done manually - so I 've followed the instructions from ...
1
vote
1answer
64 views

Changing colours in GeoPandas?

I have a very simple map (http://www.nyc.gov/html/dcp/download/bytes/nybb_15b.zip) and I have never before worked with shapefiles in any way. Can someone tell me what I need to do in order to change ...
4
votes
1answer
438 views

Configuring spatialite database access for Python 2.6.6

I'm working on a GIS project, and I would like to implement and test some geo-spatial algorithms in Python. For this purpose, I will not only need sqlite, but also spatialite, in order to store and ...
0
votes
1answer
307 views

Spatial ETL Tools won't run “AttributeError: 'module' object has no attribute, etc.”

I have a python script that runs 5 Spatial ETL tools that I wish to run as a scheduled task. Each of the tools will run successfully from ArcCatalog and also from the ArcCatalog Command line. If I ...
0
votes
0answers
25 views

How to write a QGIS-plugin to be used in IntraMaps Roam 2.4.0?

I know some python, but I have never written a plugin for QGIS nor Roam before. I like to be able to turn layers on/off in Roam I have read the Roam's wiki, and I have managed to make a plugin called ...
3
votes
2answers
78 views

Accumulated value from many rasters python/arcgis10

I need to calculate an accumulated value of temperature (as an additional raster) from many rasters. Is there any option to do this in ArcGIS 10 or any hints for a python script?
5
votes
2answers
705 views

Load and display a layer from SQL Server using PyQGIS

I'm having a go at using pyqgis from within the QGIS python console to load a layer from SQL Server and display it. I feel like I'm part way there but I'm having a real issue getting the layer to ...
2
votes
2answers
50 views

Raster image thresholding using python

I would appreciate if someone could guide me for applying thresholding technique to input raster image using Python. I intend to extract impervious surfaces from a high resolution raster such as ...
0
votes
0answers
6 views

How to set the ALLOWED_HOSTS setting in GitHub-installed GeoNode?

I installed and developed a project in GeoNode in parallel to another CMS project in Django. The CMS runs in localhost:8040 and GeoNode runs in localhost:8000. It is important to know that GeoNode was ...
1
vote
1answer
26 views

Using WK ID's when using CreateSpatialReference tool

I recently found out how to create specific spatial reference objects and add them to my arcgis python standalone script. ...
15
votes
6answers
6k views

Generate points that lie inside polygon

I have polygon feature and want to be able to generate points inside it. I need this for one classification task. Generating random points until one is inside the polygon wouldn't work because it's ...
2
votes
2answers
33 views

How to calculate field as a substring of another?

I have a text field, field1, that's populated with 14-digit identifiers, like "01234567890123". I create a new field, field2, that I want to show the first four digits of field1. I would like to do ...
1
vote
3answers
3k views

Replacing NULL values in geodatabase table?

How do you update NULL values within a geodatabase table using the ArcGIS Field Calculator (service pack 4) without changing other values to NULL? I've tried the suggestions on this previous ...
4
votes
1answer
239 views

How do I link OGR with spatialite?

Problem & Evidence: I'm trying to create a spatialite file with the code snippet below. However the outDataSource object gets assigned NoneType and all subsequent (unshown) code fails. I'm ...
13
votes
1answer
2k views

How to make a separate Python installation that can call ArcGIS' arcpy?

I see a lot of threads asking how you can create a separate Python installation (e.g. the Anaconda or Python XY distribution) that can use arcpy, while not 'breaking' the original ArcGIS python ...
2
votes
1answer
53 views

Looking to find (or build) a particular Python geoprocessing tool

So here is my situation: There is a large area (a wildlife refuge) of nearly 200,00 acres that we have loads of spatial data for, from habitat management projects from the past several years. My boss ...
5
votes
1answer
100 views

Cutting a circular buffer via Arcpy

I am currently working with compressor stations on centerline routes. These compressor stations have a 3 mile buffer surrounding them. I wish to cut a portion of the circular buffer off. These cut ...
2
votes
1answer
29 views

How to split name in label so only first two words appear?

The labels for my feature SSA_NAME are approximately 5 words long. I would like to shorten the labels to only 2 words. Every time I try a different code I receive either an error message or my layer ...
2
votes
2answers
519 views

Union multiple shapefiles with overlapping shapes

I have several shapefiles that overlap and I would like to union their geometries to get rid of those overlaps. I know how to do this with OGR and Python for single geometries. from osgeo import ogr ...
1
vote
0answers
40 views

Minidump on exit in QGIS (2.8.2- Wien) 64-bit version when using GDAL in plugin

I am working on a plugin for QGIS that is working fine on 32-bit versions but I am having some problems while using it on the 64-bit standalone installation package. I have tried on several machines ...
1
vote
1answer
51 views

If/then python for classifying existing field values to a new field

I'd like to have a tool or quick python script to classify an existing number field to a new text field. For example I have a roads layer that has a type identifier as a coded number and I would like ...
2
votes
2answers
66 views

image segmentation of RGB image by K means clustering in python

I want to segment RGB images for land cover using k means clustering in such a fashion that the different regions of the image are marked by different colors and if possible boundaries are created ...
0
votes
0answers
24 views

How to call the Qt UI of a script? [on hold]

I'm pretty new in the python world, and I'm working with the python console inside QGIS (Master version on a Debian machine). I have written some scripts, all of them are in the same directory (e.g. ...
1
vote
1answer
26 views

Gdal ReadAsArray() different values than gdal band statistics

I am confused about why if I open a band with GDAL I get, for example, band.GetMaximun(): 1000, but if I do ReadAsArray I get myArray.max(): 1200 (the same if I do np.max(myArray)). Does someone knows ...
1
vote
1answer
106 views

Restrict text widget to only integer between 0 and 999 in IntraMaps Roam

I have created a form and added an attribute as a Text widget in the Roam manager. Now I'm trying to restrict the input to be an integer between 0 and 999. I want the field to stay "empty" (or ...
2
votes
1answer
25 views

Error: Algorithm not found (QGIS)

I wrote the following code using QGIS'API. import os from qgis.core import * import qgis.utils prefix_path = os.environ['QGIS_PREFIX_PATH'] QgsApplication.setPrefixPath(prefix_path, True) ...
3
votes
2answers
225 views

How to delete column/field in PyQGIS?

How to remove or delete column fields in a shape file using python?
1
vote
0answers
48 views

Using gdal_merge to merge a large amount of files (in pairs)

I'm new to python and how it can be applied to gis. I have a large amount of MODIS files to go through and I've already extracted, reprojected and converted to GTiff the bands that I need from each ...
2
votes
0answers
28 views

QGIS QgsLayerTreeGroup signal “currentLayerChanged”?

In a pyqgis context, I use the "currentLayerChanged(QgsMapLayer *)" signal of the QgisInterface class to do something when the current layer is changed, but I need now to do the same when I select a ...
1
vote
0answers
12 views

PyQGIS Standalone Crashes python.exe when zooming out too far / Process finished with exit code -1073741819 (0xC0000005)

I have the following PyQGIS Standalone App which is working fine so far. One little problem is that if I zoom out to the MaxExtent(by scrolling the mousewheel) the app crashes python.exe so that the ...