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

learn more… | top users | synonyms

0
votes
1answer
527 views

Polygon Neighbors Analysis script (ArcPy 10.1) producing erroneous results?

I'm struggling with a python script that is supposed to calculate a field for a polygon feature class. The calculation is of the average of a field value (P_TOT_DEV) for each of a given polygon's ...
0
votes
1answer
198 views

plypython set-up

I am trying to set up plypython on the following system: Windows 8.1 PostgreSQL 9.2 64-bit PostGIS 2.0 Python 2.7.05 I have added plpython2.dll to \PostgreSQL\9.2\lib When I run: CREATE ...
1
vote
2answers
45 views

Is it possible to round all coordinates in shapely?

Following on from this question, I'm hitting a problem where thanks to floating point representations, objects aren't precisely where I expect them be after they are moved using affinity.translate. ...
5
votes
1answer
458 views

Select and copy attributes features in ArcMap using Python add-in tool?

I'm trying to add a tool to an add-in toolbar to select features from an existing feature class and copy attributes to another feature class,from point to point. TopoHeight_Field_Name='Comment' def ...
2
votes
1answer
55 views

PyQgis: During editing, add new feature attributes

Workflow: Start edit mode -> New feature is created -> On the console (pyqgis), new attributes are set -> Exit edit mode. Problem: The attributes are not saved. Only after completion of the editing, ...
4
votes
2answers
203 views

How to get into the Python API of QGIS?

After a few hours I am about to give up on finding a kind of documentation for the QGIS Python API that actually works/gives the correct information. It is obvious that there is no actual code ...
1
vote
0answers
23 views

Resampling netcdf file?

What is the best way to change the cell size of a netcdf file, keeping it as netcdf? I have looked into ArcGIS and GDAL and have not found anything yet. I prefer to use python if a solution is ...
0
votes
0answers
53 views

Element retrieval in OWL file format using python

I just created my ontology file for semantic relation using Protege. My ontology file is in the form of OWL. I need to compare two relations domain and range. But I don't know how to do it.
0
votes
1answer
23 views

How can I add points to a LineString in shapely?

I have two Polygons which intersect along one edge as shown below. I need to add the red vertices at each end of the intersection to the blue polygon. I thought I could do this with by calling ...
4
votes
1answer
54 views

How do I update joined data from MySQL programmatically?

I have a point vector layer (Sensores) in my QGIS project, I also have a MySQL database layer (SensoresDB) containing only data. I have joined these two layers in order to geographically reference my ...
1
vote
0answers
32 views

QGIS python support disabled

I'm having a problem with the python support of my QGIS version. When I start QGIS, I get the error message: Traceback (most recent call last): File "", line 1, in ImportError: Module use of ...
5
votes
2answers
87 views

Why am I getting two different outputs from Python and C++ using GDAL?

I am trying to gather information from a *.tif file using the GDAL libraries. When I open the *.tif file using both the Python API, and C++ API, I encouter two completely different answers. Here are ...
1
vote
1answer
262 views

Calculate tree cover over certain area from raster data

Last year Hansen et al. published Global Forest Change map as set of raster data available in TIFF format. Basically those are 30-meters resolution satellite images with pixel values ranging from 0 ...
3
votes
1answer
279 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 ...
2
votes
0answers
48 views

Use QGIS API on standalone python program without install the entire application

I developed a standalone python program that makes use of QGIS API to create .qml files from sld files. This is a small program of about 15 lines of code that imports the following modules and uses ...
1
vote
0answers
64 views

How to make NoData transparent?

I have been using python to turn a netcdf into a geotiff. Once I have the geotiff, I am using gdalwarp to transfer it into the right projection. Then use gdal_translate to get the tif into a vrt ...
2
votes
2answers
275 views

Convert DateTime field to Just Date in Label Expression

I have a DateTime field (ex: CreatedDate) and would like to only show the date with the label. How would I setup the label expression to do this using python?
1
vote
1answer
15 views

QgsComposerTextTableV2 minimal implementation?

I would like to use the richer data and styling API QgsComposerTextTableV2 offers. However I get this error when adding it to the composer: TypeError: QGraphicsScene.addItem(QGraphicsItem): argument ...
1
vote
1answer
29 views

How to simplify borders between polygons in shapely?

I have some fairly complex, and not completely accurate shapes stored as shapely Polygon objects. I'm trying to find the common borders, which should be as easy as finding the LineString returned from ...
1
vote
1answer
882 views

Import shapefiles into PostGIS using Python with psycopg2

I want to import shapefiles to PostGIS using Python with arcpy & psycopg2 to connect to PostGIS. I don't want to use the existing shapefile loader nor ogr, just write my own import tool. My steps ...
5
votes
2answers
2k views

Is there a way to use ArcPy module in the python shell that is not with ArcGIS?

I have ArcGIS 10.2 installed on my machine. When ArcGIS was installed, python 2.7.3(32 bits) was also installed. I need python 2.7.5 64bits for some gdal functions. So I installed python 2.7.5 64bits ...
7
votes
3answers
1k views

Is there a way to “invert” Polygons?

I have a Shapefile with Polygon features representing the world's land areas (continents, islands). Is it possible to invert these, and get a geometry that represents the world's oceans and seas? So ...
2
votes
1answer
31 views

Using zonal_stats with python in QGIS to calculate statistics for each image

I work with Python in QGIS, I want to calculate statistics for each image that I have with a specify shapefile and save result after, I tried to do like this: from rasterstats import zonal_stats ...
0
votes
2answers
35 views

How to Call ArcHydro Tools in Stand Alone Python Script

I am currently using ArcGIS ArcHydro tools to perform 'Catchment Polygon Processing'. However, it is proving time consuming to perform this for multiple rasters. How might a write a python script to ...
5
votes
1answer
102 views

Export .qml file using QGIS API

Im loading a shapefile using the method QgsVectorLayer() and adding a style to it using the method loadSldStyle() and the path to the sld file. So far so good. What I want now is to export that style ...
1
vote
1answer
67 views

Create Table with postGIS geometry in Python

I'm creating the following table with a postGIS geometry column in python but get an error psycopg2.ProgrammingError: type "geometry" does not exist What should I use to be able to use postGIS in ...
6
votes
4answers
127 views

PostGIS query for selecting features not connected to rest of road network?

I have a dataset of roads in a city stored in a PostGIS enabled database. I would like to identify and remove any feature which is not connected to the rest of the road network. This behavior is ...
2
votes
1answer
194 views

Gdal_calc works but I get a pyhon error at the end of each process

I have a problem while using gdal_calc by a .bat file. Here is the code : call "C:\OSGeo4w64\bin\o4w_env.bat" gdal_calc ...
3
votes
1answer
325 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 ...
5
votes
2answers
645 views

Auto-updating symbology between *.mxds for same shapefile using arcgisscripting?

I have a variety of .mxds for any one project I'm working on, which are all different but all use the same set of base shapefiles for my project. I know I can save a .lyr version of my initial ...
1
vote
2answers
85 views

python rasterio error

When I am importing RASTERIO then i am getting an error as: Traceback (most recent call last): File "<pyshell#0>", line 1, in <module> import rasterio File ...
2
votes
1answer
33 views

How can I retrieve private tag GDAL_NODATA from a TIFF using libtiff?

In an earlier post I reported about my attempts to read TIFF with data stored in tiles using python and libtiff. First I tried to use libtiff's function TIFFReadEncodedTile but finally I tried ...
3
votes
1answer
37 views

How to insert a variable into a tool script

I am a bit new when it comes to Python programming and this is very basic but I can't come up with a solution. I'm trying to run the GRASS r.sun plugin tool to calculate the global irradiance for my ...
1
vote
0answers
45 views

QGIS: startup.py missing [closed]

I am trying to set QGIS 2.8.1 (Linux Mint 17.2) to add the filename/path to layouts. I am using this post as a guide How to add the current document path on Print Composer? However, I haven't got ...
1
vote
1answer
45 views

Qgis -> Settings -> Customization : how to import ini file with python?

With QGIs, from "Settings"->"Customization" i can hide/show the components of the GUI. I can export a INI file with my customization. There is a way to import my INI file with a python command in ...
10
votes
3answers
2k views

Cannot run standalone QGIS script

I've been trying, along with this post, to run a script in OSGeo4w Shell, outside of QGIS. But I get the following error: ImportError: No module named qgis.core I have also read the following ...
1
vote
1answer
234 views

gdal_proximity distance to meters

I followed the answer given in this topic for searching the distance to the nearest coastline given a lat/lon coordinate. The distance output obtained is in degree (I think) but I need the distance ...
1
vote
0answers
56 views

mosaic rasters with gdal_merge.py

I want to mosaic 2 rasters "rasa" and "rasb" using gdal_merge.py . While running the code, it produces an error " No input files selected". Can somebody help me to find the error in the code? ...
1
vote
1answer
42 views

Connect / Disconnect GPS device via PyQGIS

In QGIS I would like to establish a connection to my GPS device programmatically (not via button in the GPS control panel) I found out how to get available ports with QgsGPSDetector i.e. ...
2
votes
1answer
155 views

Using ESRI Python's Geoprocessor Via mod_python

I am working on a number of geoprocessing services to be accessed solely by web clients. The traditional method of encapsulating this type of stuff in toolboxes and then publishing the toolbox just ...
3
votes
3answers
2k views

How to calculate a value based on another field under arcpy.da.UpdateCursor and cursor.updateRow?

I am trying to do a calculations under arcpy.da.UpdateCursor. I want to calculate the values for the records that have FIPS=06037. I want to take the values from "kg" column and populate the new value ...
1
vote
1answer
38 views

Foreign Key error, creating new splite db?

Attempting to use a plugin in QGIS (midvatten) that utilizes splite. I am attempting to create a db in a different EPSG than the plug in defaults to, im getting "foreign key constraint failed" as my ...
1
vote
0answers
31 views

Programmatically adding folders & layers to QgsComposerLegend

I've been building up QgsLayerTree object with a directory structure that reflects the desired legend. Specifically I'd like the Group(s) to be titles and their contained layers to legend items. ...
2
votes
1answer
95 views

How to find the intersection areas of overlapping buffer zones in single shapefile?

Find the intersections of the buffer zones I found an example where they tried finding the intersection of two different shapefiles -Intersect Shapefiles using Shapely. I've tried to adapt my code to ...
0
votes
0answers
19 views

Convert geoalchemy2 Geometry(polygon) column to OGR Geometry

I would like to use OGR to perform analysis. My data currently lives in a PostGIS database. I am loading my data into a python environment using geoalchemy2. I am hoping that a line similar to the ...
2
votes
1answer
60 views

Accessing GPS from QGIS 2.14.1/Python 2.7 /Windows10

I would like to access the device described at QGIS live GPS tracking /recommended hardware (GPS USB stick) via QGIS/Python. A gps module does't seem to be part of the standard installation of python ...
5
votes
2answers
94 views

QGIS python processing.runalg Clip returns None

I'm writing a script in pyQGIS, which would emulate measurement of a line by "walking" along it with a compass with constant length. I have a problem with the Clip algorythm from processing module, ...
2
votes
1answer
30 views

Raster brightness, contrast, saturation in PyQGIS

I'm trying to find a way to change these properties (especially contrast and brightnes) and I've found a QgsBrightnessContrastFilter class, but I can't fugure out how to apply it to my raster layer. ...
0
votes
1answer
48 views

Can I multiply fractions in map algebra?

I have a couple of rasters that show % of success in different things. I want to calculate the overall probability of success. The numerical values are integers so they represent the percentage. This ...
0
votes
1answer
39 views

Python: Running a function on all points in a list [closed]

I'm trying to get a list of cartesian points along contour lines and convert them to polar coordinates. I'm trying to run a function to convert them to polar, one for the length and one for the angle. ...