Share GPS Data

Problem Description

• Field staff for NGOs (both Humanitarian & Development) visit Programme sites with handheld GPS (e.g. Garmin eTrex).
• They collect data as they go (Tracks & Waypoints).
• They would like a way of easily sharing this information between each other:
  • uploading data to a central repository
  • managing this master repository to have a reference dataset: no duplicates, names checked for consistency
    • this management should work offline
  • download the reference dataset to each GPS
• A secondary benefit will be in terms of wider communications (e.g. reporting to Donors)
• A potential future enhancement would be to be able to download GPX routes from/to specific locations.

This requirement is defined by ​Oxfam in Haiti, but is applicable to many other organisations & locations as evidenced by this combined Problem Definition for RHoK:

• ​http://wiki.rhok.org/Sahana_Eden_Offline_Mapping

High-Level Architecture Proposal

It would be ideal if as much of the reference dataset as possible could be incorporated into the Base Map - OpenStreetMap is ideal for this.

Propose to:

• Set up a Virtual Machine containing all necessary software (to make it easy to install on any available PC - this setup may need replicating in several offices, although no need to sync between offices except via main OpenStreetMap database at this time)
• Local OSM Server
• Build a GUI within Sahana to allow the uploading/editing of GPX data

Other Options Considered

• Garmin MapSource
  • can't load more than 1 GPX file at a time
• Google Earth
  • allows access to simple, known tools for manipulating the Waypoints to download an authoritative GPX
  • treat the basemap as more static (do an initial 1-time basemap inc contours & follow this up with a process for updating the contours.osm with Osmosis)
  • doesn't work offline, although could use a KML super-overlay when offline:
    • ​http://svn.openstreetmap.org/applications/utils/wms2kml/
    • GeoServer can produce the SuperOverlay from cascaded WMS:
      • ​http://geoserver.org/display/GEOS/GSIP+47+-+WMS+cascading
      • ​http://docs.geoserver.org/stable/en/user/googleearth/index.html
    • ​mod_mapnik_wms to create the WMS
• ​Depiction
  • Data primarily only shareable with other Depiction users which means hard to gain traction even within an organisation let alone for interagency work.
  • Installation requires admin rights on the PC, which many field staff won't easily have access to - again lowering the ability to get wider adoption.
  • Can't create new Depictions or use BaseMaps at all without an active Internet connection.
  • Revealers seem very gimmicky: I don't find them useful & they're really hard to use in practise (I just wanted a 'full-screen option').
    • GeoExplorer already has the ability to dynamically edit layer opacity, which is the 1 thing I'd use them for.
  • Licensing costs push this beyond local partners to whom we want to handover the tools when moving from Response -> Recovery -> Mitigation/Preparedness (USD 200/machine + add-ons, such as $50 just for icons that come free with Sahana!)
  • No support for KML (or GeoRSS)
  • No ability to edit the OpenStreetMap base layer which adds so much value to these maps
  • Adding Elevation data is clumsy (fairly easy to make this 'seamless' ;) )

Detailed Architecture Proposal

Sahana

The current GPX layer interface is probably insufficient.

Instead have 2 tables:

• WayPoints (where each point is individually editable for a label & marker - often the raw data will just have numeric labels, so we'll need to add a prefix to distinguish for when re-labelling from written notes)
• Tracks (where all points are equal - we don't need to keep track of time or person: if we wish to see a specific track we can use the current GPX file interface for that...so maybe we keep the file uploads but add to the main table via an onaccept?)
  • ​http://www.postgresonline.com/journal/index.php?/archives/116-Loading-and-Processing-GPX-XML-files--using-PostgreSQL.html

Can we develop a Flash(?) interface to actually manage the transfer to/from the unit of the GPX &/or basemap?

Ideas from Depiction

​Depiction has some useful functionality with some nice UI ideas...there are videos which can be downloaded to review.

• Simple UI
  • add new Features to the map via the mouse inc Single/Multiple options
  • QuickAdd toolbar for common resources
  • Manage Elements tool to locate features within viewport (category, tags or name) & edit their properties (global type or individual)
    • Colour picker
    • Label
    • Icon (Image/Size)
• Modelling
  • elevation data within the database
    • can we use the same datamodel as for Mapnik's contours?
    • add an easy downloader like srtm2osm
  • models could come from GRASS or R, maybe via WPS?
    • Plumes: Wind speed, direction, volume
    • Flood
    • Liquid flow
    • Antennas (do we need this within Sahana?)
• Routing
  • road structure within the database
    • imports from OpenStreetMap
    • imports from Shapefiles
    • ​pgRouting for back-end calculations?
    • build on Measure tool (if no better ones available) for front-end UI?
• GeoReferencing
  • integrate one of the existing tools: BluePrintGISRectifier
• Shapefiles support
  • integrate OGR2OGR (usable even with basic sqlite versions) - e.g. ​Ogre
  • GeoServer via REST? (-> PostGIS where available)
• Permatext (useful for printing, especially)
• Draggable property (default based on resource type?)
• Interactions
  • Zones of Influence
    • Barriers are polygons
      • Default to octagon
      • Can create custom polygons by dragging/adding/removing polygons (UI for this already in OpenLayers)
    • Calculated (e.g. Plumes/security cameras)

Local OSM Server

• InstallationGuidelinesGISDataLinux

Edit Base Map

• Potlatch2
  • Editing local database or only main one?
  • Need better integration into Sahana:
    • passing in the area of the current viewport
    • seeing Sahana overlays inside Potlatch (can export as either GPX or OSM)

Sync Base Map

Our local install needs to be kept up to date from the global repo:

• ​Osmosis
• ​osm2gis

If we're making local edits then we need to feed those back to the master repo.

• This may be hard. Team up with ​OSM-in-a-Box to look at this?
• ​Discussion in OSM Wiki

Export to Base Map

• UserGuidelinesGISDataOpenStreetMapGarmin
  • ​srtm2osm (only needs to be run once per location - e.g. country, so can be done outside VM in Windows)
  • ​mkgmap

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