[OSM-dev] OSM Map Browser Application

Bruce Skingle Bruce.Skingle at immutify.com
Sun Dec 6 08:17:38 GMT 2009


I've been working on a map browser project, and I have some code I'm ready
to think about releasing (free, with source, under the Eclipse Public
Licence).

 

It's a Java/Eclipse based application which is capable of displaying various
kinds of map data, including (of course) OSM data. I have tested it only on
Windows, but it should run on all other Eclipse platforms including Mac OSX
and Linux.

 

There is a some information, including screen shots on my website at
http://www.immutify.com/products/maptools/maptools.html and from there is a
link to the entire online help content for the product.

 

It can display the slippy maps, as well as rendering on the fly from the XML
data returned by the OSM API.

 

I also have code which allows it to display Google Maps, Google Satellite
maps, and QCT format commercial maps, although I have removed these features
for the time being because of legal concerns. It can interface to a GPS to
provide a moving map display, but this is also removed for the moment
because of licensing concerns with the RXTX library, which is under an LGPL
license.

 

It can call the OSM API to download the XML data for the viewable portion of
a raster map and display the OSM data as an overlay, which seems fine.

 

There are a few limitations/issues which are discussed in the on line help
available via the URL above.

 

My main issue is with the interactive map which renders on the fly from the
XML API. It requests "tiles" of XML data, equivalent to Slippy map tiles at
zoom level 12 (in terms of area covered). The calls to the API are rather
slow, which suggests to me that the server is working hard to answer the
queries, and I want to get some people who understand what's happening on
the server to look at it before I release to a wider audience, hence this
email. 

 

The program caches all data and never re-requests anything it has cached
(not actually the right behaviour, but progress so far). When the XML data
is cached the rendering is a bit slow, but workable, when the data has to be
fetched it seems to be too slow however, but my main concern is the impact
on the servers if a lot of people start using it.

 

Note that this is a browser application and any calls to the tile servers or
API are as a direct result of a user viewing a map interactively, this is
not a systematic bulk download. For the tile servers I think the load is no
more than for a user viewing the map via a web browser.

 

I'm trying to write a client app, rather than implement server
infrastructure, so I'd be happiest if I can just source the data I need
online, but options to move this forward I can see include:

 

OSM provides ready cut "tiles" of XML data, this seems like a sensible
approach to me, but I might be alone. I've heard about something called
TRAPI but haven't seen much information about it.

 

I take the planet file and produce these tiles.

 

I take the planet file and produce Eclipse plugins so users can download,
say, a countries worth of data. This makes it more useful as an offline
tool.

 

I add functionality to the client to be able to process a planet file (or
extract) and users can do this for themselves.

 

So, if you would like to take a look, or would like to suggest suitable
people to do so, please let me know and I'll send you the download details
so you can try it. If you have suggestions about how to make it better, then
so much the better.

 

Regards,

Bruce Skingle.

 

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