Monday, 5 December 2011

Points of interest gadget

There are something in the region of a thousand scheduled monuments and protected historic buildings within cycling distance of where we now live. Some of them will be worth adding to OSM. I also see some of them as potential destinations or stopping points as I trundle around on the bike. I'm also trying to learn a bit about the area. So I'm interested in what is there, and where it is.

More importantly I felt like tinkering a bit with Openlayers on a smartphone.

So I've made myself a little gadget by kludging together various bits. There's a KML file of points of interest that I scraped (using Perl) from various published lists. I then edited the examples of Openlayers that use geolocation, display the OSM map, and overlay a KML file. The result is that I now have an "app" (really a web page with a slippy map) that works on a smartphone to mark Points of Interest with a pushpin. It follows me around, staying centred on my current location. A brief description of each point will pop up when a pin is touched.

For me it was a bit of a learning curve to get this working, but that says more about my limited expertise than it does about how difficult it really is. In truth none of it is very complicated.

To begin with I found it most useful at pointing out things that I hadn't noticed beforehand. Several buildings that I had been passing without a second glance turned out to be more interesting than I realised.

Now I've tried using it to locate a specific destination - and that worked fine as well. As I came home on a bitterly cold evenng it occurred to me that when our visitors arrive for Christmas and want to explore the area, we can send them out with this - while we stay warm indoors.

Pre-loading a smart phone with a collection of things that need fixing on the map seems like something that would be useful to the OSM community. An even larger group of people might like to pre-load the equivalent of a local guide-book.

But those happen to be the first two things I thought of. The nice thing is that, with the right tools in place it's fairly easy to generate data sets for displaying all sorts of different kinds of point of interest on a map.

Somebody must already have thought of this, and produced something a bit more sophisticated than my little gadget.

But who?


Chris Hill said...

I like the idea, but it depends on a good internet connection which is not guaranteed in some country areas. It also depends on someone's tiles, albeit just using the same access as anyone else's browser. OSM has continuing hassles with smart phone apps using tiles, usually because they are downloaded in bulk to cache the tiles for guaranteed offline use, something you are not suggesting.

I've started to write an Android app to draw a map that would move, rendering on-the-fly from downloaded data rather than tiles. It's a big job but once it works (if ever) it could have custom renders including user supplied extras.

It won't work in time for your Christmas guests though.

Martin, CycleStreets said...

Have you seen the Bike Hub app (iPhone/Android) and the CycleStreets app for Android, both of which have POI functionality now?

and another blog post on BikeHub about to go live.

gom1 said...

Thanks to Chris for raising the issues of scalability and connectivity, and to Martin for pointing out the enhancements to the excellent CycleStreets. Both make their points clearly, which is what we would expect. I on their other hand need to express myself better. What I had in mind was that there must be groups who want to lay their own content over a mobile map. Technically it isn't that difficult (scalability and connectivity apart), and I thought there would already be some solutions around. I can't find any, that don't involve carving out some code. I don't think it is a problem of scale or mobile signal becuase there are architecturally similar routing solutions around. Is that because I am looking in the wrong places? I think HP used to do something on ipaqs that used geolocation to drive multi-media content but I can't remember what it was called. I suppose I'm thinking of something similar (but less sophisticated)

Catriona said...


I'd be interested in trying this app. I'm looking for something that will let me pinpoint the precise location of every bench on Hampstead Heath as I walk around and allow me to add a little text to the pinpoint.

Something purely functional with no frills would be fine.