-----Original Message-----
From: Russell Mincher [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, February 23, 2000 12:04 PM
To: Lisa Cloutier
Subject: Re: MI Calculating distance between to lat and long points
Back in '97 Dan Phillips gave following formula in response to a similar
question, I believe it gives the answer in statute miles but it would pay to
check. I do recall modifying it to give me the answer in metres, I still
use it and it works very well. The coordinate pairs are in decimal
degrees.
>distance=69.093
*acos(sin(lat1*.01745329252)*sin(lat2*.01745329252)+(cos(lat1*.01745329252)*
cos
>((lat2*.01745329252))*cos((lon2*.01745329252)-(lon1*.01745329252))))*57.295
77951)
>(Where lat1 and lon1 are the first coordiante pair and lat2 and lon2
>are the second coordinate pair)
This replaced my initial method which was very tedious but did utilise MI
and I provide because it may have more use in your application:
Every year I receive the start and end positions of up to 500 dredge tows
during a biomass survey together with all of the results of data regarding
what comes up in the dredge. I then provide the scientist analysing the
data with exact tow lengths so that the data can be standardised.
I received the coordinates in an excel spreadsheet.
I used to export the data as a text file and work up each pair as a line in
a MIF.
(line Lon1 Lat1 Lon2 Lat2)
I would then import the MIF
Create a new field (column) in the table and populate it with
Update TABLE set NEWCOLUMN = objectlen(obj,"m") (remember I am working
in metres)
Then I would export the table back into excel so that I could use the
lengths calculated by MI
You can see why Dan's contribution was such a help to me, I could do the
whole thing in excel which was the format I received the data and had to
produce my results in.
I would be very interested in any alternative methods / responses you
receive
Regards
Russ Mincher
----- Original Message -----
From: Lisa Cloutier <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, February 24, 2000 5:06 AM
Subject: MI Calculating distance between to lat and long points
> Hello
>
> Does anyone know the formula or method for calculating the distance in
miles
> between to latitude/longitude points. The projection is NAD 83. Either a
> formula or a MI solution would be acceptable.
>
> Thanks,
> Lisa Cloutier
> Metricom, Houston
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