Talk:WhereAmI/OSM Binary Format

From OpenStreetMap Wiki
Jump to navigation Jump to search

Discuss OSM Binary Format here:


An implementation for binary OSM can be found here:;f=osmbinary;hb=HEAD

Currently the decoder is partially done, it is able to output all string, so it is also able to get everything in the middle :)

--Skinkie 06:17, 9 November 2008 (UTC)

optional header

Why is the 6 byte-header optional? Doesn't this break parsers? --MarcusWolschon 11:55, 6 January 2009 (UTC)

Its optional because earlier versions of scripts working with this format did not include it. Correctly written parsers for OBF should ignore types they don't understand so adding it should not break old code. It was added to provide easy Symbian recogniser support for files containing OBF (so if you send an OBF file via say bluetooth to your Symbian mobile it will know to open the file in WhereAmI). An OBF file is more complete with the header, but it contains no essential information, OBF is designed to be as forwards and backwards compatible as possible. --Adamboardman 14:55, 9 January 2009 (UTC)

32-Bit Lat/Lon Range

Why limit precision? why not map the lat/lon to the full range of signed integers: (e.g., intlon = round(lon*(0xFFFFFFFF)/180.0), intlat = round(lat*(0xFFFFFFFF)/90.0))

First of all: CPU time for conversion, second: Converting ranges forward and back may result in precision loss. Because source data has low resolution, it's not possible to make thing better. That's why precision not limited, but saved. --Socketpair
Space. --MarcusWolschon 07:14, 29 October 2009 (UTC)

Nodes Correlation

How do you correlate nodes? For example, how can you determine that two ways share nodes? Using just node's coordinates seems a bit problematic --Breki 12:41, 12 January 2010 (UTC)

Rename the page. *The* OSM Binary Format?

You bagged the name of a wiki page here to describe one possible binary format, but these days there are several, including one (PBF) which is becoming much more widely used. This format is supported by just one piece of software (according the page here). I suggest we come up with a better name (or just a codename) for this format and move the wiki page. Suggestions?

It will make more sense to newcomers if we could move towards a situation where the "OSM Binary Format" wiki page is a short page linking to a choice of several binary formats

-- Harry Wood 11:02, 6 June 2011 (BST)