Planning a longer and interesting road bike tour has become a lot easier over the last few years. In an old post I compared a few choices of trip planners for road biking and a later post explained why I switched to the Komoot platform for my planning. But next to finding the "optimal" route, longer distances also require careful planning on how to maintain good physical conditions. In other words, you should better think about food and water before starting on such a trip.
A very rough rule of thumb says that you should drink between 0.5-1 liter per hour sport. The two bottles attached to my bike hold around 1.4 liters of water and at the lower end of this rule of thumb this will suffices for 2-3 hours of cycling at around 20 degrees Celsius. Substantial higher temperatures will of course exacerbate this. With an average speed of 27 km/h this translates to around 80 kilometers. So beyond that distance I will need more than that.
Tugging another (half liter) water bottle into the back of the jersey is ok, but two bottles are too heavy. The combined weight will pull down the jersey in the back such that it starts tightening uncomfortably around the throat. But even with such a single "range extender" I will need something else on hot days and routes longer than ca. 110 km.
Note that even though these numbers look kind of theoretical, I arrived at them not by theory but by real cycling trips. Just for this post I thought it might be more instructive to motivate them from first principles.
So for such long distances I started asking myself if it is feasible to fill up the bottles during the trip at suitable places, e.g. fountains or other water taps. So it seemed that all I would need is a map listing such places.
Maybe I was looking in all the wrong places, but I could not easily find a good website to do this. Once I started to focus my search around OpenStreetMap, I discovered OpenPoiMap shown in the screenshot below:
Selecting "Food shops" in the top left menu area allows to select "Drinking water" in the right hand pane and sure enough candidate places are now easily visible on the map.
Even though this is so close to a real solution for my problem, the fact that it will /not/ show any POIs above a certain zoom factor renders it completely useless for my use case. With the maximum zoom factor still showing data I can view an area of around 9x9 km^2 and so I would have to do a lot of scrolling to scan potential routes for interesting places.
/* Drinking Water in Baden-Württemberg */ area[name="Baden-Württemberg"]; node(area)[amenity=drinking_water]; out;