[postgis-users] question on returning area size using st_area.

[Sidney Cadot]

> Tells me that it wants the units to be in degrees?  So then, what is  
> the 0.0174xx number there? Once again, I can only speculate, but I  
> am assuming that perhaps this is a conversion to meters or some  
> other standard unit at some point on the map (perhaps at the prime  
> meridian).

It's the conversion factor to get from degrees to radians, i.e. Pi/180;

     angle_rad = angle_deg * 0.01745329251994328.

(actually it should be 0.01745329251994330 ...)

Hope this helps.

Sidney