[OSM-dev] DBF files (shapefile) and OSM tags

Kristian Thy thy at 42.dk
Mon Jan 1 01:18:52 GMT 2007

On Sat, Dec 30, Nick Whitelegg wrote:
>> The columns in a shapefile's attributes have a fixed width, and that
>> width is reserved for each shape. So the space usage will be
>> approximately equal between using a single, concatenated column and
>> multiple columns.
>> What did you intend to gain by concatenating the columns?
> What I was wondering about in particular was how to make the shapefile DBF file
> fit in with OSM's data format (where there is technically a limitless number of
> valid tags). Having one attribute column per OSM tag would presumably mean that
> any shapefile generating application would only be able to use a particular
> subset of tags.

Couldn't you just add all used tags as columns? As far as I can tell,
OGR allows adding fields on the fly (and if you're not using OGR, why?).


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