Python in geoinformatics
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The document provides an overview of using Python in geoinformatics, highlighting its capabilities, common pitfalls, and various frameworks like ArcGIS and QGIS. It explains how Python's scripting can extend geospatial data management and visualization through tools such as KML and pyproj. Additionally, it mentions the importance of community support and available resources for learning Python in this field.
Python in geoinformatics
- 1. Marianna Zichar University of Debrecen
- 2. Agenda Motivation The language (with the main pitfalls) ArcGIS KML QGIS Projections Visualization Analysis and management of geospatial data 2
- 3. The language General-purpose interpreted, interactive, high-level programming language Multiple programming paradigms Object-oriented Imperative Functional programming Procedural Dynamic language: Scripting Non scripting 3
- 4. The language Python code can be packaged into standalone executable programs Popular open source lots of tutorials and online resources very active community 4
- 5. Main pitfalls of Python Indentation identifies blocks of code Case sensitivity = is used to assign values == is used to test conditions 5
- 6. Python in geoinformatics? YES! Thousands of different modules and packages are available to extend the functionality of Python containing several ones related to geoinformatics. 6
- 7. ArcGIS 7
- 8. ArcGIS Arcgisscripting (ArGIS 9.x) Arcpy (ArcGIS 10.x) automate geoprocessing tasks manage map documents and layers find and fix broken data links edit data in feature classes and tables 8
- 9. Creating KML files XML 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. 9
- 10. QGIS Python 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 Plugins It 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 Applications Custom applications can be developed based on QGIS API. 10
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- 13. Projections Pyproj ”wrapper’” around library called PROJ.4 Class: Proj longitude, latitude native map (x,y) coordinates Class: Geod performs various Great Circle distance and angle calculations npts() method: calculates the coordinates of a number of points spaced equidistantly along a geodesic line 13
- 14. Projections Translating UTM location into latitude and longitude 14
- 15. Visualizing geospatial data Mapnik toolkit: to build mapping applications Heavily used by OpenStreetMap, because it produces images which are ideal to include in webpages. 15 Geospatial data from PostGIS database, shapefile, any other format supported by GDAL Clearly rendered images
- 16. Analyzing and manipulating geospatial data Shapely package for manipulation and analysis of two-dimensional geospatial geometries. Based on the GEOS library. 16
- 17. Conclusion Do 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. 17
Editor's Notes
- #3: Motivation: VBA ->
- #4: It was created in the late eighties and early nineties Python supports multiple programming paradigms, including
- #6: compact; there is no begin/end (or similar) statements to identify blocks of code colon
- #8: demonstrates a number of ways how to use Python in ArcGIS.
- #9: site package . In ArcGIS 9.x Python was just an option to perform geoprocessing tasks, although it was installed automatically with ArcGIS. Since the support of VBA will end totally after the version 10, every developer has to select a new platform.
- #10: Every piece of information is enclosed by tags
- #11: http://www.qgistutorials.com/en/docs/find_neighbor_polygons.html It is probably not surprising that the open source Python is ready to support an open source GIS software product too. Python can be used in several ways in QGIS:
- #15: Two Proj objects
- #16: works with geospatial data from PostGIS database, shapefile, or any other format supported by GDAL, and produces clearly-rendered, good-looking images
- #17: https://pypi.python.org/pypi/Shapely Manipulation and analysis of geometric objects in the Cartesian plane. Shapely uses the GEOS library for all operations. GEOS is written in C++ and used in many applications and you can expect that all operations are highly optimized. The creation of new geometries with many coordinates, however, involves some overhead that might slow down your code.