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

[HARVEY, PHILIP O NH-03 USAF AFMC 412 OSS/OSW]

See Ed Williams' Aviation Formulary at http://williams.best.vwh.net/avform.htm for great circle distance, etc formulas.  The formula you desire is only requires 1 line and can easily be written into a function.

Phil


-----Original Message-----
From: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org] On Behalf Of wendi harjupa
Sent: Tuesday, November 01, 2016 2:01 AM
To: GrADS Users Forum <gradsusr at gradsusr.org>
Subject: [gradsusr] convert world coordinate distance to real distance (km)

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