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

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Find polygon centroid with Python

I'm using ArcGIS 9.3 to find centroid of some polygon features. I'd like to do this in Python, but so far I can only find solutions with VBA. Can anyone provide some leads here?
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1answer
1k views

Batch intersect from a text file using Python (ArcGIS)

I am attempting to modify my code below which reads from a text file of shapefiles and executes an intersect and outputs them to a user specified location: import arcpy, sys, os from arcpy import env ...
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2answers
1k views

GDAL Clipping (hack)

I am trying to use the python script from http://www.sparkgeo.com/labs/2010/07/07/gdal-clipping-hack/ to clip a raster based on many shapefiles. The script is using a mysql database an i would like to ...
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2answers
1k views

With Python and ArcGIS, how do I add features to a featureclass?

In ArcGIS Python code: CopyFeatures_management copies features to the same featureclass - that means overwrite to the feature class. How can I add new features to one featureclass or namely different ...
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2answers
322 views

Is code completion available in QGIS Python Console?

I wanted to know if the autofill functionality is available in the python console for QGIS as the one available in ArcGIS Desktop's Python Console or am I supposed to hardcode it.
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1answer
820 views

ArcPy - Dataframe rotation - Getting a polyline length wise in the dataframe in layout view in ArcMap

EDITED: I'd like to rotate my dataframe until a polyline fits dataframe-width wise in the layout view of a .mxd. If the lines runs north/south I would like the dataframe rotated until the line is ...
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2answers
3k views

Help with ArcGIS10 Python and SearchCursor reading Null values in field

I'm using a Python script to count the number of unique string values in a feature class. My script works if there are values in the field but if there are any NUll values in the field it crashes. Any ...
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1answer
549 views

How can I, in a general way, rescale a raster in ArcGIS Model Builder

What I want to do is rescale a few rasters from whatever they are now (i.e., values between -99 and +1000 OR -256 - +256 OR 0 - 3.23) to a normalised value (i.e. values between 0 and 1). I would ...
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3answers
3k views

Using QGIS with a pre-existing installation of Python 3.2 and matching GDAL

I need to have GDAL/OGR working with Python 3.2 because of another dependency. However, I also want to have QGIS for convenience. However, QGIS - FWTools in particular is built against Python 2.5, ...
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2answers
3k views

How to automate point-in-polygon queries in ArcView?

Layer1 = point shapefile (multiple points, geocoded) Layer2 = polygon (1 attribute; (1,2,3...)) I want a non-gis person to be able input a single address and be told the attribute of the polygon ...
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2answers
300 views

How to use any ArcMap tool from a python script?

I'm trying to develop a tool that uses some of arcmap default tools like the Sketch Tool or Trace Tool. Is it possible? Let me explain a little more, I need to draw a feature, ask for user input, and ...
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2answers
168 views

How to iterate over layers and export them as PNG images with PyQGIS in a standalone script

I would like to export specific layers as a png from a QGIS .qgs map. From the table of contents the script would first export the "boundary, climits, and Div1_Irrig_1956_0" layers as one png. The ...
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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, ...
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1answer
51 views

Suppressing rasterio verbosity

I have the following script using rasterio: if not os.path.isfile(out_dir + os.sep + name_adm1 + '.tif'): with rasterio.drivers(): with rasterio.open(constants.ras_cmask) as src: ...
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1answer
67 views

QGIS corrupted processing tool

I've been dealing with various problems after re-installing QGIS and other GIS-related software (see QGIS corrupted plugins upon reinstallation). The solution worked for a bout a day and now I lost ...
2
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1answer
50 views

How to multiply a user-defined input parameter with a field value within the graphical modeler?

I have the same Question as asked in this post (How to connect input parameter to the field calculator algorithm within the graphical modeler?) and the answer from Joseph already helped a lot: ...
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2answers
98 views

PackageLayer_management failing within script, needs to run outside of an ArcMap session

I'm automating a workflow that requires outputting a layer package, it throws the general ERROR 999999 when executing and breaks. It does, however, generate a folder in the correct directory, with ...
2
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1answer
65 views

Getting script file name as object in Python? [closed]

I'm quite new to Python and programming in general. I have created a few scripts using Python and as part of my framework/best practices for my scripts, I'd like to display when a script begins and ...
2
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1answer
53 views

Fastest way to process OSM

I've been working with imposm and Python, it's fairly easy to parallelise. I've hit a performance problem when trying to associate the coordinates to the ways. Creating a dictionary from ...
2
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3answers
138 views

ASCII file with latitude, longitude and data to GeoTiff using Python

I have a .asc file with three columns of data: longitude, latitude and a data value. Each latitude and longitude point represents the location of a centriod of a 1/8 degree unprojected grid. I want ...
2
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1answer
218 views

geopandas spatial join extremely slow

I am using the code below to find a country (and sometimes state) for millions of GPS points. The code currently takes about one second per point, which is incredibly slow. The shapefile is 6 MB. I ...
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2answers
42 views

How to select form the attribute table in with ogr

i want to select the (Sumava) from the attribute table and then make a shape file, my problem is i don't know which function should i use to select this area.if any one can help me? import ogr import ...
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2answers
153 views

Generate TIN from elevation data in Python (no Arc)

I would like to generate a 3d terrain model of an area, and I am stuck on creating the TIN (which I will convert to an STL). I know there are plenty of ways to use ArcGIS, QGIS, 3DEM, and various ...
2
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1answer
68 views

Create new shapefile based on values ranges in existing shapefile using gdal/ogr/python

I have a shapefile containing many thousands of polygons with values stored in an attribute field and ranging 0-105. I would like to create a much simplified file that contains classes for value ...
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2answers
217 views

Find country from GPS coordinates, offline using python

I'm aware that there are several similar questions already but I have been searching for days and not been able to solve my problem: All solutions I've found require GDAL, which I have not been able ...
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4answers
293 views

Python Library for converting GeoJSON Multi-polygon to polygon

I would like to know if there is a Python library that can be used to convert GeoJSON Multi-polygon to a Polygon. Note: i want to convert .geojson file Multi-Polygon feature type to Polygon feature ...
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3answers
146 views

Search and concatenate Landsat bands with Python

I have a number of Landsat geotiff (*.TIF) file in a folder. The problem is simple, I need to search certain Landsat bands from that list and make a composite tif image. I am using Orfeo Toolbox's ...
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3answers
232 views

How to create a Projection from a CRS string using pyproj?

I'm trying to convert between two coordinate systems using pyproj: import pyproj p1 = pyproj.Proj("+init=EPSG:4326") p2 = pyproj.Proj("""PROJCS["NAD27 / California zone ...
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2answers
149 views

Merging features (lines) in shapefile with same name using Python and QGIS?

I am working with the NHD flowline dataset (USGS) and some of the line features have the same name. I want to merge the line features that have the same name. For example: There are three features ...
2
votes
1answer
127 views

HDF5 and georeferencing?

I'm doing quite heavy processing of Earth Observation data, and it appears that a lot of my workflow can be speeded up by using HDF5 for local storage. I mostly work with large stacks of raster files, ...
2
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2answers
71 views

How to load stored composer from project file in standalone QGIS application?

I would like to load a .qgs file and get a composer from it, but I can't figure out how. Is there a way, or do I have to read the xml myself and individually set the appropriate values for the ...
2
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2answers
128 views

Store in a python list the attribute table of a vector in QGIS

I'm stuck with a very simple issue.. I've loaded in QGIS (through the py console) a csv layer (no geometry) made of 4 fields and 3 rows: #load the csv layer = QgsVectorLayer("path/to/the/csv", ...
2
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1answer
65 views

Dissolving a TIN using python/ogr binding

I have a TIN model where I remove some of the triangles (see fig. 1). Most of the triangles touch on one edge, some on one vertice. I would now like to generate a polygon shapefile containing the ...
2
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2answers
65 views

How to successfully do “nested” looping over a Fiona collection

I wrote some code that basically loops over all features in a shapefile with Fiona in Python, doing some things, calculating some things, etc. I found that it would exit the for loop prematurely, ...
2
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1answer
97 views

python crashes with returned gdal band object from a function

I wrote these two functions in a module when I want to read the band in NetCDF or HDF files and return the band outside the function. Each HDF and NetCDF has many subdatasets. Each subdataset in a ...
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1answer
143 views

How to launch Processing tool User Interface using PyQGIS?

I am trying to launch the UI of a processing algorithm using Python script but I cannot find a simple way for it (aside double clicking on it in the process toolbox of course). The plugin is a water ...
2
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1answer
159 views

How to find if map layer registry is empty?

In my script I want to open layer named my_layer if it is in the map layer registry. I use following code for it: inputLayer = QgsMapLayerRegistry.instance().mapLayersByName("my_layer")[0] If not ...
2
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1answer
105 views

How to create a new empty memory layer with fields scheme from other layer in QGIS?

Being a complete noob with python so far, I got inspired by this answer: http://gis.stackexchange.com/a/155988/8202 to dive into it a bit. When creating features in a new target layer from an ...
2
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1answer
71 views

QGIS re-write loop efficiently, assign number to every row of a column,

I have a column titled CompanyNam and I need to extract the ownership information. For example, if CEZ is the first company then, I assign to it number 1, then Sokolovska is the next number, etc. If ...
2
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2answers
180 views

Reserved Ampersand Character in Label Expression of ArcGIS for Desktop?

I have this code which works... def FindLabel ([NUMBERNAME], [NUMBER], [BLOCK], [SURNUM]): lineone = "A:"+ [NUMBER] absName = "<CLR red='255'><FNT size = '14'>" + [NUMBERNAME] ...
2
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1answer
69 views

How to add a message bar to custom canvas?

There is a simple code to add message bar to main window in QGIS: iface.messageBar().pushMessage("Hello","World") My question is how to add bar to my custom canvas canvas = QgsMapCanvas() in ...
2
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2answers
246 views

QGIS/Python script to generate random points many times

Good day. Can anybody provide a simple code to be run in the Python Console of QGIS (I am using 1.8 Lisboa) to generate X number of random points (say e.g. 5000) over a certain global shape of ...
2
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1answer
81 views

Replace Expression in Field Calculator to include a Numeric Range

There has to be an easier way to clean up address data, I hope? GeoCoding, I need to remove APT# and any number or letter that follows.
2
votes
1answer
148 views

problems overwriting files in ArcSDE with python script

I'm having a great deal of difficulty overwriting files when using ArcSDE. The usual 'arcpy.env.overwriteOutput' method doesn't seem to work. When I run this script: import arcpy from arcpy import ...
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2answers
298 views

How to make a movie from a ascii grid files?

Lets say I have several ascii grid files for each time step for a particular location. I would like to spit out the image for each of these ascii grid files and legend on the side bar. I also would ...
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3answers
526 views

PyQGIS - load PostGIS layer as editable

I can load a PostGIS layer on QGIS' map canvas but "Toggle Editing" button comes "inactive". How can I load vector layer as editable? The code given below loads PostGIS layer on map canvas & ...
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2answers
330 views

How to use `layer.getFeatures()` in a standalone script?

I am following the QGIS Cookbook and this post where it concerns reading attributes from layers. I would like to exploit this method and implement it into a standalone script. Essentially, I want to ...
2
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1answer
1k views

Install gdal in python on Windows7

I'm having problems installing the gdal library for python. I use a Windows 7 and have WinPython 2.7.9.2 which runs Python 2.7.9. I'd like to use gdal + Python for raster manipulation. I've read ...
2
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2answers
256 views

What is the “best” way to automate the GIS slope and aspect algorithm?

I am currently obtaining slope and aspect of roofs using ArcGIS as follows: Mosaic several Lidar .asc files to new raster Extract by mask using Mastermap building outlines to get hold of just the ...
2
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1answer
235 views

Python tool won't stop running— Not an infinite loop issue

I'm having trouble with a python script. It is essentially a near duplicate of another script which is running fine-- it is using different files, but apart from that the tools used and the order in ...