josephg at gmail.com
Thu Oct 16 01:17:16 BST 2008
On Thu, Oct 16, 2008 at 3:07 AM, Jochen Topf <jochen at remote.org> wrote:
> On Thu, Oct 16, 2008 at 03:49:11AM +1200, Joseph Gentle wrote:
>> On Thu, Oct 16, 2008 at 3:18 AM, Andy Allan <gravitystorm at gmail.com> wrote:
>> > 'Better' is dependent on what you're trying to achieve, but there are
>> > certainly many 'different' representations in use in different
>> > projects.
>> I want to represent the data such that a user can pan and zoom a map
>> around smoothly (25+ fps) without pre-rendering tile images.
>> Especially on devices like the iphone, that would be really nice.
>> The only data structure I can think of to do something like this would
>> be a quad tree with internal nodes containing data at particular
>> detail levels. (So that for a fixed size view you never have to
>> inspect more than a fixed number of quad tree nodes).
>> Basically, it would look the same as the current tile set; but
>> prerendered tile images would be replaced with node&way lists listing
>> the data the corresponding tile shows.
>> Has anyone written a program like this; either with that sort of data
>> format or solving that problem?
> Have a look at "navit". Although 25+ fps is somewhat optimistic for a
> mobile device... (http://wiki.openstreetmap.org/index.php/Navit)
> I use postgis for live rendering of OSM data and generally it is very fast.
> But OSM has huge amounts of data and you'll have to make compromises
I think 25fps is ambitious but possible on devices such as the iphone
which have hardware accelerated graphics capability.
More information about the talk