Developing Geospatial Solutions using Open Source

2007-04-11T21:15:26Z

Wiki-HuxFc9:

This is one of the three books identified by the [[Education Committee Work Program|Education and Curriculum Committee]] that should be written. The other books are [[Using Open Source GIS]] and [[Developing Web Mapping Solutions Using Open Source]].

== Approach for writing this book ==

Using the application and programming language categories from http://freegis.org we'll gather problems or use cases, maybe divide them into subproblems, and describe how they can be solved using the free tools.

The tools are [[Programming Languages Project|programming languages]], libraries, command line tools, and customizable applications.

This book is about "I know which problem I need to solve and it can't be solved, at least easily or without trouble, by simply using some free GIS tool".

We exclude web mapping problems from this one since it is the topic of book 3.

Provide here an analysis of the meta problem description above.

Copy the categories and

programming languages: C, C , Java, Python, Tcl/Tk, Perl, (Visual) Basic, PHP, C#, Fortran, Delphi, Ruby, SWF, Other (Other has zero entries in freegis.org).

== GPS related ==

*Problem: Share GPS data between applications
**Subproblem: Parse GPX
**Explanation: GPX is an XML application for GPS data. Parsing gives us the GPS data.

*Problem:
**Subproblem: GeoTag Media
**Explanation:

*Problem:
**Subproblem: Track logs
**Explanation:

*Problem: Edit a GPS track
**[http://users.skynet.be/watermael/gps/50358.html#to_Moissac example data]
**Requirements: Show the track on a map as editable lines, show the coordinates on a spreadsheet allowing edits, link the two representations
**Subproblem: Import the GPS track to the editor
**Subproblem: Export the track from the system

*Problem: Merge GPS tracks
**Explanation: Allow you to view several GPS traces, delete certain points, and average others together.
**Use: You survey a route several times, and want a single trace of the best average over the traces

{| class="wikitable" style="text-align:center" border="1" cellpadding="2"
| Use case || Description || Perl || Ruby || Python || Shell
|-
| Parse GPX
| [http://www.topografix.com/gpx.asp What is GPX?]
| [http://search.cpan.org/~rbow/Geo-Cache/lib/Geo/Gpx.pm Perl based solution]
| [http://www.tom-carden.co.uk/googlegpx/upload-gpx Ruby based solution]
| [http://cheeseshop.python.org/pypi/pygpx/ PyGPX]
| [http://mpa.itc.it/markus/useful/shp2gpx.sh shp2gpx.sh] and [http://mpa.itc.it/markus/useful/gpx2shp.sh gpx2shp.sh](scripts calling 'gpsbabel')
|-
| GeoTag Media
|
| [http://rdfweb.org/people/danbri/media/bin/geoloc_media.pl RDFWeb geoloc_media.pl] ([http://locative.us/photomap/geoloc_media.pl original geoloc_media])
| Ruby?
| Python?
| Shell?
|-
| Track logs
|
| [http://search.cpan.org/~rgibson/Geo-Track-Log-0.02/lib/Geo/Track/Log.pm Geo::Track::Log]
| Ruby
| Python
| Shell?
|-
| Track merge
|
|
| Ruby?
| Python?
| gpsbabel can perform related [http://www.gpsbabel.org/htmldoc-1.3.0/Data_Filters.html GPS track operations]
|}

== Projection-Conversion ==
* Problem: Convert between WGS84 and local projections
* Problem: Convert from lat long to easting and northing, as used on printed maps

Check out the [[Axis Order Confusion]] issue which arises whenever adressing geographic coordinates with IT systems.

{| class="wikitable" style="text-align:center" border="1" cellpadding="2"
| Use case || Description || Perl || Ruby || Python || Java || JavaScript || Shell
|-
| Change between projections
| Perform a Helmert Transform
| [https://secure.mysociety.org/cvstrac/dir?d=mysociety/perllib/Geo MySociety Code]
|
| [http://gagravarr.org/code/#geo_helper geo_helper.py]
| [http://www.jstott.me.uk/jcoord/ Jcoord]
| [http://www.jstott.me.uk/jscoord/ JScoord]
| [http://proj.maptools.org/ cs2cs tool]
|-
| Convert from lat long to easting northing
|
| [http://search.cpan.org/~toby/Geo-Coordinates-OSGB-1.07/lib/Geo/Coordinates/OSGB.pm Geo::Coordinates::OSGB]
|
| [http://gagravarr.org/code/#geo_helper geo_helper.py]
| [http://www.jstott.me.uk/jcoord/ Jcoord]
| [http://www.jstott.me.uk/jscoord/ JScoord]
| [http://proj.maptools.org/ cs2cs tool]
|-
| Work with old maps / data in Cassini Projection
| Convert between Cassini and its base elipsoid
|
|
| [http://gagravarr.org/code/#geo_helper geo_helper.py]
|
| [http://www.ponies.me.uk/maps/cassini/ cassini-coord.js]
|
|}

== GPS and EXIF ==
* Problem: Extract GPS exif tags from photos
* Problem: Add GPS exif tags at the time a photo is taken
* Problem: Add GPS exit tags to photos, based on the time they were taken and a GPS track

{| class="wikitable" style="text-align:center" border="1" cellpadding="2"
| Use case || Description || Perl || Ruby || Python
|-
| Get GPS EXIF data
| Extract lat and long from GPS Exif tags
|
|
| [http://www.benno.id.au/code/pexif/ pexif]
|-
| Set GPS EXIF date
| Add lat and long GPS Exif tags
|
|
| [http://www.benno.id.au/code/pexif/ pexif]
|}

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Developing Geospatial Solutions using Open Source