# Distance between latlongs varies in different projection systems?

I have shapefiles with correct projections. The SRS is EPSG 32735 (WGS 1984 UTM 35S)

Now, I have these two coordinates from this projection system:

(31.3751,-23.4388) and (31.3779,-23.4355).

Obviously the coordinates (format and value) will vary on different projection systems, and there in lies my confusion.

I used the following link to calculate the distance between the two points: http://www.movable-type.co.uk/scripts/latlong.html

I copy pasted the lat/longs exactly as shown above and the distance it gives me is 0.313 meters. But I'm not sure if this is correct at all, since the calculator didn't ask me for any projection system? So:

1. Does this mean the projection doesn't matter to calculate the distance?
2. Does it differ between different projection systems?
3. Is the tool I'm using incapable?

Thanks,

Kaushik

• 0.313 meters is incorrect. When I use the web site you link to I get 441.7 meters and, indeed, this is the geodesic distance on the surface of the ellipsoid. In fact, a more accurate distance is 441.504 meters. However, the geographic coordinates are only specified to the nearest 0.0001 degree, about 10 meters, so interpret the distance accordingly. (BTW, I interpreted your coordinates as (lat,lon). If you meant (lon,lat), the distance is 464.158 meters.)
– cffk
Commented Sep 18, 2013 at 14:19
• P.S. The more accurate geodesic calculator I used is geographiclib.sourceforge.net/cgi-bin/GeodSolve
– cffk
Commented Sep 18, 2013 at 14:26