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I've found these GPS charts to be helpful in correlating what I think
happened to what really happened during a race. I like to do this as
soon as possible before I forget the details. Making the chart sounds
much more complicated than it is. Now that I have it figured out,
it takes about a half hour to do. If you have any questions click here to
contact me.
Before You Start:
- You'll need a cable to connect your GPS to your computer so you can
download the track data.
- Set your GPS to record your track at the
desired intervals during the race (I use 15sec.).
- After the race, download the track data
from the GPS. I use a program called GPS TrackMaker which can be downloaded
for free from: http://www.gpstm.com/
- Save the track data in Garmin PCX5 format.
This creates a file listing your track data and waypoints in a text format that can be easily edited.
- Open the Windows "Edit" program
by clicking <Start>, <Run>, Enter "EDIT" in the
<Open> box, and click <OK>.
- Open the PCX5 you just saved from
TrackMaker.
- If you wish, delete all of the track data before the start and
after the finish and delete any waypoints you don't want. Delete only the lines of data, not the header lines before
each section. Track data lines begin with "T" and waypoint lines
with "W". Be sure to delete the entire line.
- Copy the position at each desired interval from
the track data to the waypoint area at the bottom of the list. Copy each
line up through the "Alt" column.
- Change the first letter of each line you've
copied to
"W" to indicate it is waypoint data rather than track data and type
in a name for the waypoint. Do not change the original track data lines. The names can be anything, but I use the time
from the start. The ":" character is not allowed so use 105
instead of 1:05. Make sure the columns line up
with the original Waypoint data columns.
- Save the edited track.
- Open the file again with GPS TrackMaker and
zoom/pan to display the track as desired. You can "Right-click on any of
the waypoints to change the symbol.
Continue below if you want to save the image as a picture.
- Copy the screen onto the Windows
clipboard by pressing and holding down the "shift" key.
While holding the "shift" key down, press the "Print
Screen" key.
- Click on <Start>, <Programs>,
<Accessories>, <Paint> to open the "Paint" program that
comes with windows.
- Click <Edit>, <Paste> to paste the
contents of the clipboard into the Paint program.
- Trim the picture by changing the height and
width. Click <Image>, <Attributes>, and change the height
and width as desired. Click <OK>. If you trim off too much you can
click <Edit>, <Undo>. Caution! You can only undo the
last 3 edits you performed.
- When you are finished, click <File>,
<Save As>, Enter a name for your chart, and click <OK>.
My choice of editors for manipulating the data is (in order of preference):
-
edit.com - This is the old dos text
editor. Included up through Windows XP. To start the editor, click:
"Start", "Run:, type "edit" in open box and click "OK". Use "Exit" from
the file menu to exit the editor. If you click the close button in the
upper right corner, you will get an error.
-
Notepad - Try to open tracklog file.
If it looks like garbage, move up to Wordpad. Choosing "Save" (as
opposed to "Save as") will save the file with the same name and
extension instead of automatically changing the filename extension to
"txt").
-
Wordpad - Save as plain "Text
Document" (not msdos format).
-
MS Word - Use only as a last resort!
Save files as "Plain Text" only.
-
Here's some answers to your questions:
- I haven't been able to get GPS Tracker to recognize the waypoint data I added to the PCX5v2.06 file.
You entered a lowercase "w". It must be a capital "W".
- I want to make sure my GPS is setup correctly so I can get the best data.
I have my tracklog set to:
Wrap When Full - This is a personal
preference. After about 9 hours (with interval set to 15 secs) the
tracklog starts back at the beginning and begins to overwrite the
previously recorded data.
Recording Method: Time
Interval: 15 seconds - This makes sure
you have data in between waypoints. It shows small variations in course
that can cause you to lose a few boat lengths. It also helps if you lose
reception for a few seconds.
- Should I keep my GPS off until I start and save the data right after the race to get the right data stamp.
I turn mine on/off when I leave/return home. With 9 hours recording time it's not a problem.
- Do you delete the track files from your GPS after you download the info to your computer?
Yes/No It depends on if I think of it or not. I can save them in my GPS also.
- I like how you figured out the start and finish times.
The first thing I do is save the complete tracklog to my computer with the current date in the filename and then
save it again using the date of the race followed by "_race" for the file name. This is good insurance against mistakes! If you don't already
have the starting mark as a waypoint in your tracklog, add it.
Next delete all data points that are more then a couple of minutes before or after the race. Select a single
point by clicking on the track a minute or two before the start of the race. Make sure only one data point is selected (a little red dot) and
press the "Delete" key to remove it. This "breaks" the tracklog at that point. Select all data points in the part of the track you don't want by
double clicking on it. If you get more than you want to delete, click somewhere off the track to de-select it and try again. One you have
selected the proper points, press the "Delete" key to remove them. Keep deleting portions of the tracklog until you have just the data you
wish. Save the data under a different name (I use the date of the race followed by "_race". You can add a number at the end if there was more
than one race on the same day.
After removing all of the extra data points, you can usually see where the start and finish were. If you know the
exact times, it's easy to find them in the tracklog (you'll probably
need to compensate for the GMT offset). Also: Most times I make a turn just before the start and after the finish. If you've
recorded with a short enough interval, you can find the turns on the track within a few seconds.
- GMT is about 4 hours ahead of us.
Offset from GMT is in whole hours. It can be found on your GPS setup Time page. It should be 4 hours, depending on Daylight Savings Time.
- My track data is broken into different sections - seems like I should be able to combine the different sections into one section for all the track data?
The tracklog should be one continuous list of data points.
This happens every time you turn your unit off or it loses reception. Try locating it where it has a better "view"
of the sky. You can "paste" the sections together by removing the header and blank lines.
"H LATITUDE
LONGITUDE DATE TIME ALT ;track"
- As I understand it once GPS Tracker recognizes the waypoint then I amend the name field to speed data.
You can change the name at any point by changing the name in the tracklog using the text editor.
If you don't add a name, it won't be recognized as a waypoint. Note: This waypoint name format
i.e., 5.kts) works in GPS Trackmaker; however some GPS's/Software
won't accept it and will refuse to display the waypoints (or
possibly the entire track). It this happens you will have to figure
out another format for the waypoint names (Hint: the "." is most
likely the problem).
- When you download from your GPS do you upload all routes, waypoints and tracks or just tracks and amend waypoint list and skip the route data?
I usually download just the tracklog and waypoint data from the
GPS. I download routes only to edit them on my desktop computer and then
upload them back to the GPS.
- My file includes lots of tracks dated 31Dec 89 with a 0:00:00 time stamp. Not sure if
can delete this track info? Does your file have similar data like this?
No. I'm not sure where they came from, but you should be able to delete them. They
may have
been "saved". Look in your manual for how to delete saved tracklogs. If
you can't find your manual, they can be usually be downloaded from the manufacturer's website. For example: http://garmin.com.
- I did get one of my new waypoint (1002) to show up once even thought I couldn't figure out how.
See #1 above.
- Is there any reason to upload the amended file into my GPS?
NO
- GPS Tracker doesn't show the new waypoints nor does it identify the correct number of waypoints
in the file, although it appears to identify the correct number of points.
The program ignores all lines after one with an error. See #1 above.
- Is there something I need to do in GPS Tracker under tools, maps, or tracking for
the software to fully recognize my file waypoints.
No, see #1 above.
If you have any questions click here to
contact me
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