The following converts latitude co-ordinates in cell A3 from NN:NN:NN and
N:NN:NN format to N.NN format. (A similar formulae does the same for
longitude co-ordinates.)

=IF(RIGHT(A3,1)="W",IF(MID(A3,2,1)=":",(LEFT(A3,1) )+(MID(A3,3,2)/60)+(MID(A3,6,2)/60/60),(LEFT(A3,2))+(MID(A3,4,2)/60)+(MID(A3,7,2)/60/60))*-1,IF(MID(A3,2,1)=":",(LEFT(A3,1))+(MID(A3,3,2)/60)+(MID(A3,6,2)/60/60),(LEFT(A3,2))+(MID(A3,4,2)/60)+(MID(A3,7,2)/60/60)))

It is complicated as it needs to accommodate source information in degrees
in NN and N format (others are given in NN format) and, of course, the
output to be both positive (east of Greenwich and north of the equator) and
negative. Is there a better (shorter) formulae that will do the same job?

Thanks.

Bill R