[josm-dev] bug in JOSM - moving objects introduces scaling

[Tobias Wendorff]

Dear Community,

I started to port some of my geodetic functions from PHP to JAVA.

One of my first affords is a drastical improvement of the measurement
plugin. It directly works on the geoid (no, it's not Vincenty).

The error for distance is ZERO up to 15 km and then it's about
3 cm for 50 km ... however the performance is great.

Distortion of area measurement is a little higher (some millimeters),
but still acceptable.

You can download the compiled version here [1] - I'm going to
release the sourcecode and a mathematical description in the next
days! More later.

Using this new function, I was able to detect a bug:
When you create a perfect rectangle [2] and move it some meters,
it gets scaled in size.

25 km to South-West introduces a scaling of 1,0068%.
Even duplication of a way or node introduces a scaling of
1,0005% and changes the angles of the rectangle!

Oookay ... the scaling is pretty low, but I would like to fix
it. Could anyone tell me, where duplication is calculated?

Please report results & opinions about the new measurement-plugin.

Best regards,
Tobias

[1] http://raumplanung.tobwen.de/OSM/JOSM/measurement.zip
[2] http://raumplanung.tobwen.de/OSM/JOSM/square.zip