Robert G. asks:
I have a client who is interested in providing their trail network for users to download to their handheld GPS receivers. After searching extensively, I have not been able to find a solution to what I thought would be a simple process: How to convert existing GIS data into a format that can be downloaded onto any GPS receiver, without having to convert the data each time. Ideally, the file would be converted once (or at least once per receiver manufacturer), and provided for download via their web site.

GPX, the GPS Exchange Format, has become the de-facto standard for delivering GPS and GIS data to consumer-grade GPS receivers. GPX files can be used by hundreds of GPS receivers and mapping programs, including ExpertGPS, Google Earth, MapSource, MapSend, and MapCreate. Ten years ago, there simply wasn't a common file format, so you had to distribute different files for each brand of GPS receiver (and usually, several different formats for the GPS receivers within a single brand). GPX has changed all of that.

I happen to be one of the founding fathers of the GPX file format - I helped write the initial GPX 1.0 file format, and have written and maintained the GPX documentation since day 1. ExpertGPS, as you might expect, uses GPX as its native file format, and is widely used as a GPX authoring tool and GPX file converter.

Converting GIS shapefile data to GPX

Once you configure ExpertGPS to use the same coordinate format and datum as ArcMap, you just click Import on the File menu, and select your shapefile data. ExpertGPS Pro will convert your .shp polylines and points into GPS tracks and waypoints. Click Save to save the trail network in GPX format. Your data is ready to be distributed - anyone who downloads the GPX file from your Web site can send it to their GPS using their favorite mapping software. (If they don't have software, EasyGPS is GPS freeware that works with any GPS.

An ExpertGPS user asks:
When I trace a stream over the map in ExpertGPS, why does ExpertGPS connect the end of my drawn shape back to the beginning?

The short answer: because you are drawing with a filled shape type. ExpertGPS allows you to assign a cartographic style to the objects you draw on the map. Every shape, track, and waypoint in ExpertGPS has a Type that you assign. You define the cartographic style (color, line pattern, fill color) for that Type in the Edit Type dialog (the Edit Shape Type dialog is shown below). For Routes, Tracks and Shapes, you can choose a fill pattern. Obviously, only filled objects should have a fill pattern. A lake would have a blue fill. A stream, being a linear object, shouldn't have any fill. It should just have a blue line color.

Automatic Closing of Filled Shapes

When you draw a new object on the map, and assign it a filled shape type, ExpertGPS automatically closes the shape (by connecting the last point you drew back to the beginning point). Otherwise, you'd end up with lakes with holes in them, and your map would get all wet!

You can manually close any route, shape, or track by selecting it, right-clicking, and clicking Close. To save you this effort, ExpertGPS does it automatically when you assign a filled type to something you've just drawn on the map.

So, if you are tracing the lakes, ponds, streams, and creeks of your area off the topo maps, you should create two Shape Types: Lake and Stream. Lake would have a Solid fill, and Stream would have fill set to None. Choose the Lake type for any body of water (lake, pond, reservoir) and Stream for any linear waterway (stream, creek, canal).

To learn more about the power of ExpertGPS' cartographic styles and types, read Working with Types in the ExpertGPS Help File.