Using Josm on a mac (v.2561). When I download OSM server maps, they’re out of proportion relative to how they appear on the standard slippy map (and reality!). They’re vertically squished by a small amount, but enough for me to notice this problem. I tried josm several months ago and had the same problem. Both times I’ve started from scratch without changing any preferences.
Check what map projection JOSM is set to: on Edit → Preferences, map settings (third icon down).
Make sure it is set to “Mercator”, then the maps should look right (and the same as the slippy map)
If its set to WGS84 (or something else) it will make the map look squashed out of shape.
That worked perfect, thanks! I was hoping it would be a simple fix.
Out of curiousity… I can’t yet imagine a use for the original proportions josm gave me. If there are some, would they be important enough to give preference to them over the same proportions as the slippymap, as josm does?
Presumably OSM uses Mercator to simplify tiling. But, compared to reality, Mercator is the squished one.
JOSM’s default has been switched from WGS84 to Spherical Mercator a long time ago, exactly because these questions about squished appearances kept popping up.