Freemap – OpenStreetMap for UK countryside users Nick Whitelegg Southampton Solent University

Motivations Around 10 years ago I did a long-distance walk from the south to the north of England I wished to illustrate the walk with maps However, Ordnance Survey licencing at that time did not permit including OS maps due to copyright issues This was the motivation to seek an alternative solution

GPS surveying Around the turn of the millennium, consumer GPS units were becoming more widely available This opened up the possibility of creating your own maps from scratch Maps could be created from GPS tracks, recording where you’ve been

Freemap – original approach Originally, only bends in paths marked with GPS waypoints; it was thought recording an entire track would use too much server space Waypoints joined together, and the resultant paths classified, using editing software Resulting data uploaded to a server Server-side software generated maps from a standard MySQL database using GD (graphics library) Original Freemap launched 2004

Early problems encountered Non-surveyable features (contours, water bodies, woods) Contours produced from freely-available NASA Shuttle Radar Topography Mission Other features produced from Landsat aerial imagery How to distinguish different types of path UNIX-style permissions for foot, horse, car traffic (0=no access 1=access) These permissions used in rendering

Discovering OpenStreetMap Around early 2005, I discovered the OpenStreetMap (OSM) project Like Freemap, OSM sought to produce free mapping data, but on a global scale Once OSM was mature enough, I contributed Freemap data to OSM and reworked Freemap to get data from OSM’s web service Later, Freemap DB populated with a static data download from OSM

Subsequent development (c. 2007/08) Developments in Freemap then mirrored those in OpenStreetMap itself Map rendering in OSM matured, using a high- quality rendering library, Mapnik (mapnik.org) Freemap therefore moved from standard PHP/GD to Mapnik for rendering As AJAX gained in popularity, interactive features (e.g. ability to annotate footpaths with problems, etc) were added

Subsequent problems As OSM data grew in size, the memory demands of the data import process grew The demands of server-side rendering also grew with increased volume of data Being a not-for-profit project, this caused some issues with subsequent development of Freemap for a while

Client-side rendering kothic-js ( is a recent project to render map data client-side using HTML5 Canvaswww.kothic.org/js With the server-side problems encountered, this looked an interesting option Initial tests have suggested that performance is acceptable, and could be further improved with HTML5 techniques such as local storage The in-development Freemap 0.6 takes this approach

Client-side rendering: architecture Google-style “slippy map” front end When map moved, AJAX request sent to web service Web service supplies data in JSON format kothic-js renders data in user-specified style

Other features, besides the map Existing sites (e.g. Ordnance Survey get-a- map) have been examined to obtain ideas on how to enhance Freemap User-contributable walking routes are a commonly-encountered feature Users can contribute walking routes, and share them with other users A long-standing feature has been addition of annotations (e.g. directions; problems such as blocked paths)

Android app development These days, every website comes with a companion app Freemap is no exception; OpenTrail ( map.org.uk/downloads/android/opentrail.apk) aims to provide in-the-field navigationwww.free- map.org.uk/downloads/android/opentrail.apk Currently uses raster maps but will switch to vector Will also be able to “play” walking routes so that you see the walk directions in-the-field on your phone

Developing an open-source project: final thoughts Enjoyable but very time-consuming! Work and other commitments can restrict available time for development A lot of patience needed! With no money coming in, expect to have to make compromises Certain development approaches not possible due to high memory demands Restricted dataset Requires that you keep up-to-date with the latest development techniques Rewarding to be part of a community striving for open ideals A great way to keep “on top”of your subject and keep your skills up-to-date!