[OSM-dev] Scale of downloaded images seems to vary.

[Bjoern Hassler]

Hi Tom, dear friends,

I'm not really sure what you mean by geographical scale?


It would be helpful to have text like this:

"This image is 90.7 dpi, or 28 dots per cm.
If printed at this dpi, the scale will be 1cm to 25,000 cm."

Particularly if the formula is complicated, then it would be helpful to
retrieve this information from the libraries.

The online map has a scale bar super-imposed - how is that produced? Maybe
the relevant information could also be read as part of that.

Regarding the missing DPI information in the png: It would be great to add
it. But with the above statement, at least the user is warned, esp. if that
led to a wiki page with additional information. So not too bothered about
getting it all right or make it all explicit, but it would be really
helpful to provide a link so users don't have to hunt around (as I did, and
I do a lot of work with OSM...).

Many thanks!
Bjoern
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