Blueprint for GIS Import/Export

XML

We need to be able to Import & Export these XML formats to/from the Database:

• GeoRSS (URL fetch/publish)
  • Export done
• GPX (File upload/download)
  • Export done
• KML (File upload/download & URL fetch/publish)
  • Export done
• OSM (File upload/download)
  • Import/Export done, but currently only a few Feature Classes mapped
• GML (? Low priority, not used much in real world)

Other formats which may be useful are Shapefiles, PostGIS & JSON.

These should be representations added to the RESTlike controller.

Rather than reinventing the wheel, we could consider wrapping ​FeatureServer to do a lot of this work for us (like Web2Py uses CherryPy) since it is WSGI-based.
Alternatively we could look to borrow code from it.

The XML conversion is probably best-done using XSL stylesheets:

• ​http://sourceforge.net/projects/geofunctions/

Relevant XSDs:

• ​GeoRSS
  • ​http://georss.org/xml/1.1/georss.xsd
  • ​http://georss.org/xml/1.1/gmlgeorss.xsd
• GPX
  • ​http://www.topografix.com/gpx/1/1/gpx.xsd
  • ​http://www.topografix.com/gpx_for_developers.asp
  • ​http://home.online.no/~sigurdhu/MapSource-text.htm
• GML
  • ​http://schemas.opengis.net/gml/3.2.1/
• KML
  • ​http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd
• OSM
  • ​http://dev.openstreetmap.org/~kleptog/osm-0.5.dtd

Sahan Eden uses S3XRC for our XML Import/Export which uses lxml:

• lxml: ​http://codespeak.net/lxml/index.html#introduction
  • Fast Parser: ​http://blog.ianbicking.org/2008/03/30/python-html-parser-performance/

Other options are available:

• XML export from Web2Py: ​http://michaelangela.wordpress.com/2008/03/29/exporting-a-web2py-table-in-xml/
  • KML export from Web2Py: ​http://groups.google.com/group/web2py/browse_thread/thread/b59bd3a9c40086f0
• PyRXP: ​http://www.reportlab.org/pyrxp.html
  • Faster & optionally validating (DTD, XSD?), but requires compiling into Python so less portable (unless using pyexpat wrapper)
  • PyRXP_Documentation.pdf
  • XSD->DTD conversion (our schema are in XSD format)
    • ​http://crism.maden.org/consulting/pub/xsl/xsd2dtd.xsl
    • ​http://weblogs.asp.net/rchartier/archive/2006/03/21/440782.aspx
    • ​http://lists.xml.org/archives/xml-dev/200504/msg00757.html
    • ​http://bytes.com/groups/xml/85935-converting-xsd-into-dtd
• cElementTree - included in Python 2.5, strict & fast: ​http://effbot.org/zone/celementtree.htm
  • mytree=xml.etree.ElementTree.XML(request.body.read())
• sgmlop (supported by xmlrpclib): ​http://effbot.org/zone/sgmlop-index.htm
• pyexpat (non-validating & slower, but built-in to Python 2)
  • ​http://docs.python.org/library/pyexpat.html
• Pyfo (example with Web2Py): ​http://michaelangela.wordpress.com/2008/04/10/simple-xml-creation-with-python/
• SAX: ​http://www.devshed.com/c/a/Python/Parsing-XML-with-SAX-and-Python/

CSV to KML Converter:

• ​http://code.google.com/apis/kml/articles/csvtokml.html
• Useful to extend to handle images (multiple images => Tabs)

This is another option for Import (via Python structures):

• ​http://www.rexx.com/~dkuhlman/generateDS.html

XML links:

• ​http://www.w3schools.com/Schema/schema_intro.asp
• ​http://diveintopython.org/xml_processing/index.html
• ​http://www.xml.com/pub/a/2002/09/18/py.html
• ​http://www.xml.com/pub/a/2003/09/10/py.html

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Geotagged Photos

We should also be able to import Geotagged Photos & have these display on the Map.

Feature Metadata already includes an Image - so the work needed is just in terms of reading the Lat/Lon from the Tag & providing a UI:

• ​http://en.wikipedia.org/wiki/Geotag#JPEG_photos

Most developed OSS tools are:

• ​Exiv2 - C++ with ​pyexiv2 binding (still experimental)
• ​ExifTool - Perl (extra dependencies & needs to be run as system call)
• Comparison: ​http://www.picurl.org/development/wiki/Exiv2vsExifTool

Python works-in-progress here:

• ​http://sourceforge.net/projects/exif-py/?abmode=1
• ​http://www.ivan-herman.net/cgi-bin/blosxom.cgi/WorkRelated/SemanticWeb/xmpextract.html XMP-only
• ​http://code.google.com/p/python-xmp-toolkit/ XMP-only

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GIS BluePrints