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“Waypoints”, geographic position markers created either in a GPS unit or using software, have been a function found on virtually every GPS unit ever made. More recently, “Points of Interest” or POIs have been implemented as an alternate way to store data for a point position, and many recent GPS units let you upload your own custom POI lists. POIs provide a handy way of organizing groups of points, and can also include more information on a point than a standard waypoint. I’ll be doing a short series of posts on creating and manipulating POIs. While the focus will be on Garmin GPS POI capabilities, other GPS manufacturers also support them as well, though usually in different formats. Note: As far as I know, only Garmin GPS units that use external data storage cards (like those listed in this post) can accept custom POI data.

Here’s a comparison table listing some of the characteristics of both waypoints and POIs:

As an additional comparison, here is one data point on my Garmin, stored and displayed both as a POI, and as a waypoint saved and modified from the POI data. The data point is from a database of uranium mines in Arizona, generated from a point shapefile. First, the data screens:

POI Data Screen	Waypoint Data Screen

Even after stripping out the labels (”Status”, “County”, etc.), it’s impossible to fit all of the data on the POI screen into the waypoint screen. In fact, there’s unused data space on the POI screen above, since you can have two lines of “Name” data at the top, and can also fill out the four data lines all the way to the end; on the waypoint side, every bit of data space is taken up.On the map display:

POI Map Display (with custom POI icon)	Waypoint Map Display (with standard icon)

The POI map display shows the full first line of the POI name, which can be up to 48 characters long (although this will be more like 20-25 in practice); the waypoint shows the maximum name length of only 14 characters. The POI icon covers a size of 24 x 24 pixels in this case, and there’s no limit to the number of custom icons you can create for a POI database. For the waypoint, I used a mine symbol, supplied with the unit; you can create a custom waypoint icon as well, but its size is limited to 16 x 16 pixels.So, for importing and using some kinds of point datasets in Garmin GPS units, POIs offer some useful features above and beyond what waypoints can do. Next post in this series will talk about the Garmin POI data format, how to create a POI-compatible file, and how to convert between POI data formats and those for GPS waypoints.

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Actual screenshot