Eventually I did it… the cycle version of Tiramisù is here. Actually, it’s a very preliminary version, but it should mostly work ok.
The base theme
The cycle theme draws paths according to the MTB tags when available. The colour scheme is the same of the hiking version, I just added a darker brown for MTB 0 (SAC starts from 1). Untagged paths are shown in grey, at higher zoom levels the SAC scale is shown with bullets up to T3. T4 and above are a dotted thinner line, T5 and T6 have transversal red and black bars to show they aren’t suitable for bikes. I chose to differentiate T4 because (if you happen to be a vertrider…) it is sometimes rideable, and also because there is a number of mistagged paths that are actually in the T1-T3 range.
Tracks are rarely tagged for MTB, so I left the basic tracktype classification unchanged. When there is MTB tagging available it is shown in form of dashed core with rounded linecaps. Colours are the same used for paths. To help differentiating higher grades have shorter and more spaced dashes.
Uphill scale is shown in the form of a circle drawn on top of the path/track. Colours match the ones used for downhill. I stole this from Dsvilko’s Simply Hike theme.
The predictive “Oronzo” version
I don’t really know how this is going to end up, but I wanted to try to interpret the available data to guess MTB difficulty on paths where the MTB scale is absent. The idea is to automate the mental process I’m doing anyway when I look at a map without MTB indications.
Analysis on tag usage on tagwatch (just before it died) showed a certain correspondence between SAC and MTBscales, that sort of confirms experience on the terrain. For example amongst the trails with a T1 SAC classification 62% have a MTB 1, 26% are MTB 2. So, as a base I match the two scales, adding a bias in case of bad trail visibility (that usually means not so rolling terrain).
Codenamed “Oronzo” this isn’t a working theme at the moment, but a proof of concept for testing. It only shows paths that have both SAC and MTB tagging and some basic land use for orientation. A line is drawn according to the real MTB scale. The colours are the same of the main theme, except MTB 0 which is green to stand out more. On the top of that two concentric circles are drawn: the inner one shows the SAC scale, the outer one the SAC+visibility bias. When the line colour coincides with the circles the system works, else you can check how much it screwed up.
Anybody with a lot of time to waste can pan around to check how well it works and share his opinion. :-)
Quite a few things. The final (distant) goal is to have a theme that is complete for cycling, both off and on road, showing everything relevant. At the moment network routes aren’t shown, nor are restricted accesses. Cycleways should be better highlighted, too.
I’m also not really happy with the rendering. There is simply too much stuff to show at once. It’s difficult to differentiate things enough to be easy to distinguish at a glance and at the same time avoid a total mess of colours and symbols… The great news is that Mapsforge 0.5 will have modular themes and much more control on line-symbols which will solve the problem (I hope). Until then I think this is more or less the best I have to offer, but I’m open to suggestions.