Elevation info for Garmin Glide Ratio functionality

[Jack Glendening]

I've just upgraded from a Garmin 12XL to a GPSmap60csx GPS. That has
the added functionality of giving the current "Glide Ratio" and "Glide
Ratio to Destination". It seems most new Garmins have this feature,
which is obviously useful for us but does require that waypoint
elevations be specified. So I wrote a simple Perl program to convert
an on-line Soaring Turnpoint Exchange CAI file data into a wpx
waypoint file containing waypoint "elevation" fields. Since others
might have a similar need I've put it on-line at
http://www.drjack.info/MISC/SOAR/GPS/convert_cai2gpx.pl
though its use of Perl makes it useable only by a small number of
pilots.

I've been able to read its output file with Garmin's MapSource
software and use that to upload the waypoints to my GPS, but use of
G7toWin also works. I've only used this with the CAI file for my
local area and with my GPSmap60csx and so offer it on a "if it works
for you that's great" basis as I don't plan to worry about other GPSes
or possibly anomalous CAI files.

For the waypoint elevation I used the airport elevation plus 1000 ft
as a buffer (also putting the true field elevation in the comment
field as a reminder) but others may want to use other values. There
are some other caveats noted in the program - in particular, I had
some difficulty specifying symbols which would appear as other than
the default "blue flag" so while airports appear with an "airport"
symbol the non-landable waypoints use a "Glider Area" symbol which in
older GPSs appears as a glider but in mine appears as a
hangglider-like triangle.

Jack Glendening

[Cliff Hilty]

Interesting Dr Jack! I have the Garmin 196 and have
that fuction, but I input the destination altitude
in the setup/vnav/arrival altitude box. The only drawback
is that you have to set it each time you change a waypoint
unless the altitude is the same. There fore I use it
as final glide ie I set it to my final destination
and leave it unless in eminent danger of landing out
then I set to that airport or field elevation +800'.


At 03:48 29 July 2007, Jack Glendening wrote:
>I've just upgraded from a Garmin 12XL to a GPSmap60csx
>GPS. That has
>the added functionality of giving the current 'Glide
>Ratio' and 'Glide
>Ratio to Destination'. It seems most new Garmins have
>this feature,
>which is obviously useful for us but does require that
>waypoint
>elevations be specified. So I wrote a simple Perl
>program to convert
>an on-line Soaring Turnpoint Exchange CAI file data
>into a wpx
>waypoint file containing waypoint 'elevation' fields.
>Since others
>might have a similar need I've put it on-line at
> http://www.drjack.info/MISC/SOAR/GPS/convert_cai2gpx.pl
>though its use of Perl makes it useable only by a small
>number of
>pilots.
>
>I've been able to read its output file with Garmin's
>MapSource
>software and use that to upload the waypoints to my
>GPS, but use of
>G7toWin also works. I've only used this with the CAI
>file for my
>local area and with my GPSmap60csx and so offer it
>on a 'if it works
>for you that's great' basis as I don't plan to worry
>about other GPSes
>or possibly anomalous CAI files.
>
>For the waypoint elevation I used the airport elevation
>plus 1000 ft
>as a buffer (also putting the true field elevation
>in the comment
>field as a reminder) but others may want to use other
>values. There
>are some other caveats noted in the program - in particular,
>I had
>some difficulty specifying symbols which would appear
>as other than
>the default 'blue flag' so while airports appear with
>an 'airport'
>symbol the non-landable waypoints use a 'Glider Area'
>symbol which in
>older GPSs appears as a glider but in mine appears
>as a
>hangglider-like triangle.
>
> Jack Glendening
>