python in geoinformatics

Python in geoinformaticsMarianna Zichar

University of Debrecen

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AgendaMotivationThe language (with the main pitfalls)ArcGIS KMLQGISProjectionsVisualizationAnalysis and management of geospatial data

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The languageGeneral-purpose interpreted, interactive,

high-level programming languageMultiple programming paradigms

Object-orientedImperativeFunctional programmingProcedural

Dynamic language: Scripting Non scripting

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The languagePython code can be packaged into standalone

executable programsPopular

open sourcelots of tutorials and online resources very active community

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Main pitfalls of Python Indentation identifies blocks of codeCase sensitivity= is used to assign values== is used to test conditions

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Python in geoinformatics?YES!

Thousands of different modules and packages are available to extend the functionality of Python containing several ones related to geoinformatics.

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ArcGIS

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ArcGISArcgisscripting (ArGIS 9.x)

Arcpy (ArcGIS 10.x)automate geoprocessing tasks manage map documents and layers find and fix broken data linksedit data in feature classes and tables

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Creating KML filesXML based language to describe features with geospatial information

Simple text file

Modul: xml.dom.minidom

Assuming that you are already familiar with reading shape files or geodatabases you can now write your own function to export data.

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QGISPython Console

The integrated Python console is ideal for scripting. When the console is started the modules qgis.core and qgis.utils will be imported automatically.

Python PluginsIt is possible to create and use Python plugins to enhance the functionality of QGIS. The plugin installer allows users to easily fetch, upgrade and remove Python plugins.

Python ApplicationsCustom applications can be developed based on QGIS API.

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ProjectionsPyproj

”wrapper’” around library called PROJ.4Class: Proj

longitude, latitude native map (x,y) coordinates

Class: Geodperforms various Great Circle distance and angle calculationsnpts() method: calculates the coordinates of a numberof points spaced equidistantlyalong a geodesic line

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ProjectionsTranslating UTM location into latitude and longitude

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Visualizing geospatial dataMapnik toolkit: to build mapping applications

Heavily used by OpenStreetMap, because it produces images which are ideal to include in webpages.

Geospatial data from PostGIS database,

shapefile, any other format supported by

GDAL

Clearly rendered images

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Analyzing and manipulating geospatial dataShapely package for manipulation and analysis of two-dimensional geospatial geometries. Based on the GEOS library.

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ConclusionDo you maybe know additional packages?

There are several packages which support geoinformatics, and from which I overviewed some, pointing out how useful is to get to know Python language.