fun with POI

POI are like stripped down waypoints that live in your GPS. You can use them to manage large numbers of locations, subvert your firmware waypoint limitations, etc. You can hack, convert, and sort your POI using gpsbabel.

The POI files are very simple. They contain 3 comma-separated text fields, and an optional fourth field. To leverage an example from the link above:

long,lat,title,description
-110.12345,44.98765,"ACME Shoe Store","Phone: 555-829-8293"

POI are textfiles that have a .csv extension. They are not Excel files, although your windows box probably uses Excel as the application handler for .csv files. Do you see the difference? Trying opening the file in Notepad to see them in their natural state. Many things that have been unclear will be revealed unto you....

Why POI and not waypoints

To quote Red90 in this thread:


Waypoints:
- Amount limited by firmware - Sorted by icon only.
- 14 characters in name and 30 in comment field.
- Can be viewed at any zoom level
- Can be deleted and added from the unit.
- Can use the "Geocaching" feature.

Custom POIs:
- Amount limited by card space only.
- Sorted by file name.
- 44 character in name and 88 in comment
- Can be viewed up to 200 meter (or is it 300 meter?) zoom level only (at the moment).
- Can not be deleted from the unit. Waypoints, however, can be individually created from a POI on the unit.
- Can have proximity alarms built into each POI from the computer files.

I would also add that POI can be organized into different databases for easy storage, maintenance, and use.

converting your .gpx to POI (.csv)

gpsbabel -i gpx -f example.gpx -o garmin_poi -F example.csv Later versions of poiloader can use .gpx files directly so you may not have to do this.

converting your .kml to POI (.csv)

gpsbabel -i kml -f example.kml -o garmin_poi -F example.csv

the file structure on your microSD card

'\' contains .gpx track files, one per day
'\Garmin' contains gmapsupp.img, your map image
'\Garmin\Poi' contains poi.gpi (can be renamed, can contain many files in the directory than one file in).

find the POI within a certain distance

Should all be on one line. Replace the in/outfile names, distance, lat/lon with your own values.
The example below takes the original.csv file, finds points within 1.5 miles of some lat/long reference point and writes them out to nearby.csv.

gpsbabel 
	-i garmin_poi 
	-f original.csv 
	-x radius,distance=1.5M,lat=33.0,lon=-96.8 
	-o garmin_poi
	-F nearby.csv

Note that unless the points are very close to you there is no need to specify a great deal of precision in your reference point.
more details

sorting the POI by distance

Note that if you run the distance filter immediately above and give it a Very Large Radius (like 10000m) it will include all the POI. You will just have the side effect of being sorted by distance from the reference point you specify.

POI-related links

$Id: poi.orb,v 1.1 2009/01/05 02:40:35 mouse Exp $

You can if you are not a spammer. My public key is here.