[gradsusr] convert world coordinate distance to real distance (km)

[wendi harjupa]

Dear every one

I have problem with converting distance in world coordinate to distance,

I have map with
lon = 135  135.5
lat = 34.5   35

I want to set lon =135, as 0 km, and lat=34.5 as 0 km.
as we know that 1 deg is about 110 km.

Is there any function in grads that can directly convert the world
coordinat distance to real distance (km)?

Please, any help would be very appreciate.

thank you
regards,
wendi
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20161101/778ab920/attachment.html