Math help needed - Warning complex equation!!....read only if brain is in stable conditon

grayrest grayrest at grayrest.com
Thu Feb 6 16:22:31 CET 2003


Jay wrote:
> right, now that I got your attention, I need help on the following
> piece of python code:
> 
> distance = 1.15 * (180 * (acos((sin(pi * lat1 / 180) * sin(pi * lat2 /
> 180)) + (cos(pi * lat1 / 180) * cos(pi * lat2 / 180) * cos(pi * (lon2
> – lon1) / 180))) / pi) * 60)
> 
> when trying to compile I get the error "SyntaxError: invalid syntax".
> 
> Uses Math libray, pi is a defined constant (lat1, lat2, lon1, lon2 are
> variables - two sets of latitude and longitude values)
> 
> Using Linux Red Hat 8.0, Python 2.2.2
> 
> I've counted the number of brackets (11 in total both sides) there and
> they do match, so I can't really see anything obviously wrong with
> this.
> 
> there is a handsome reward available for the solution
> provided....(hehehhe)
 >>> def rad(deg): return 180.*deg/pi
...
 >>> lat1,lon1,lat2,lon2=60.78,  161.80, 66.92, 151.52
 >>> lat1
60.780000000000001
 >>> 
distance=1.15*(180*(acos((sin(rad(lat1))*sin(rad(lat2)))+(cos(rad(lat1))*cos(rad(lat2)) 
* cos(rad(lon2 -lon1))))/pi)*60)
 >>> distance
328.4917120736846

Taadaa! I'm pretty sure it's the "-" as has already been suggested. I'd 
also break it up if I could to make it more readable.
-- 
grayrest
http://grayrest.com/moz





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