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Table of Contents
Share GPS Data
- 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:
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.
- 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:
- GeoServer can produce the SuperOverlay from cascaded WMS:
- mod_mapnik_wms to create the WMS
Detailed Architecture Proposal
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?)
Can we develop a Flash(?) interface to actually manage the transfer to/from the unit of the GPX &/or basemap?
Local OSM Server
Edit Base Map
- 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:
If we're making local edits then we need to feed those back to the master repo.
Export to Base Map