Using the Marengo GPS Route Planner

Contents

Introduction

The Marengo GPS Route Planner is a web service to allow you to use Google Maps to define a route (specifically a set of waypoints) which you can upload to your GPS.

It has been designed primarily for use with the Garmin Edge (TM) series of GPS-enabled bicycle computers, but because it is built around open specifications, it will be of use on many other GPS devices. See here for an introduction to why this site was built.

Planning Your Route

Name Your Route
When you first start the Marengo GPS Route Planner, the text box entitled "Route Name" is highlighted. Enter a name of up to 10 characters in here to identify the route on your GPS once it's been uploaded.

Find Your Start Point
Now find your starting point. Use the slider on the left side of the map to zoom in and out, and drap the map around to change the area you are looking at. You can use the overview map in the bottom right hand corner to move further more quickly.

Set a Waypoint
Once you've located your start point, simply click on the map! Be as accurate as you can - GPS units these days are very accurate, so position your waypoints with care to ensure that the GPS warns you at the right moment. You may find that switching to Satellite view on the main map may help with your accuracy. Many areas don't have high-resolution satellite images in Google maps yet, so this may or may not be of use to you. Note that, once you've placed a waypoint marker on the map, you can drag it around, so you may find it useful to place markers roughly to start with, then zoom in and place each one more accurately.

Name Your Waypoint
When you click on the map, you'll see a box appear to the right of the screen, under the title "Waypoints". You can enter some text in here which your GPS will display beside the waypoint. On the Garmin Edge series of GPS units, at least, a waypoint's name cannot be longer than 8 characters. The Marengo GPS Route Planner requires up to four of these to ensure each name is unique, so this leaves you with four,five or six characters to give you a hint as to what to do at the waypoint. This is actually sufficient - you can use the following codes (or make your own up, of course):
  • ON - carry on
  • R - turn right
  • L - turn left
  • 2L - take second left
  • BR - bear right
  • BL - bear left
  • SO - straight over
  • CYCP - cycle path
  • GATE - through gate
  • ...etc.

Deleting a Waypoint
If you've added a waypoint somewhere you don't want it to be, simply click on the red marker on the map and then click on "delete this waypoint" in the balloon.

Finding a Waypoint
If you want to locate a particular waypoint, click on its underlined number in the waypoint list. This will cause a balloon to be displayed over that marker on the map, and the map to be centred around the point. Conversely, if you "hover" over a map marker, this will automatically select the waypoint's text in the waypoint list. This makes it really easy to enter waypoint text to existing points: just hover and type.

Inserting a Waypoint
You may find you want to insert a waypoint between two others. To do this, click on the waypoint BEFORE the one you want to insert and select "Insert waypoint after this one" (you will not see this option on the last waypoint as all new points are automatically added after this one). A new waypoint will be added halfway towards the next waypoint, and it will be displayed with its balloon showing.

Using "Lines"
For speed, the Marengo GPS Route Planner doesn't draw lines between waypoints by default. However sometimes it can be a little unclear as to which waypoint follows which. If you click on the "Lines" button in the Tools menu, a blue line is drawn from waypoint to waypoint to make the order clearer. Note this will cause things to slow down slightly if you have lots of waypoints.

Saving Your Route

To save your route, click on the "GPX" button. This pops up a window containing the GPX code describing the route. GPX is a code format which is designed to be non-proprietary and hence should work with many GPS units. This code needs to be saved to a file. Press "Ctrl-A" to highlight the whole of the GPX code, and then copy this text to the clipboard (Ctrl-C, or Edit->Copy from the menu). You can then open up a text editor (e.g. Gedit or Kate in Linux, TextEdit on the Mac, or Notepad under Windows) and paste the code into the editor. Once you have done this you can save it wherever you like. It is advisable to give the file a .gpx extension.

Note that there are two buttons on the "save" box - "Strip" and "Reverse". The "strip" will regenerate the GPX code without any waypoints which have not had a comment assigned to them. This allows you to add more waypoints to your route than you really need, to allow for more accurate distance estimation, but ensures they don't get uploaded to your GPS. The "Reverse" option will reverse the order of the waypoints to allow you to generate a return journey. Also if it finds a "R" or "RIGHT" comment, it replaces it with a "L" and vice versa.

Searching / Geocoding

There is a text box next to the "Route Name" box marked "Search". If you enter a town / city name, or full postal address in here, and press enter, the program will attempt to centre the map on that location. Please note that, as of writing, this doesn't work in many countries because of ludicrous legal/copyright restrictions. The UK, Japan and China are some of these countries. It seems to work fine in the US.

Uploading Your Route to Your GPS

Once you have saved a .gpx file (see above), you can then try to upload it to your GPS unit. To do this, you will need to download a free (open source) utility called GPSBabel, which works on Linux, Macs and even Windows. You can find it here. Under Linux, the command line required to transfer a GPX file to a Garmin Edge device is (assuming that your GPX file is called "foo.gpx") : 
    gpsbabel -r -i gpx -f foo.gpx -o garmin -F /dev/ttyUSB0

I've written a small script to wrap this call to make it a bit easier to remember. You can grab a copy here.

For Windows, you can issue a command from the command line the following (assuming again you've got the sample GPX file saved as "foo.gpx"): 
    gpsbabel.exe -r -i gpx -f foo.gpx -o garmin -F usb:

Please note that this service has been tested with GPSBabel 1.2.8 - if you experience problems, please ensure you are running the same (or a higher) version.

Loading a Route

Loading a GPX route into the Marengo GPS Route Planner is the reverse of saving. You'll need to open the GPX file in a text editor (Gedit, Kate or Notepad), select all the text (Ctrl-A), copy it (Ctrl-C), then paste it into the "Load" popup window in the route planner.

Hints and Tips

Don't Define Too Many Waypoints
There will be an upper limit on how many waypoints you can define in your GPS unit. On the Edge units, it's 100. Therefore you should only really place waypoints where you definitely need direction. However, as you will have noticed, the waypoint list shows a distance by each waypoint - this is the straight line distance between that waypoint and the previous one. You may therefore want to add more waypoints simply to allow the distance measurement to be accurate. If you are doing this, ensure the "extra" waypoints have no comment associated with them. You can then and use the "strip" functionality when generating the GPX file (see above): this ensures that only the commented waypoints will get uploaded to the GPS unit. You'd probably want to save two copies of this route: one as the full GPX and one as the "stripped" version for upload to your GPS.

Trust the GPS
If you follow the above advice and only place waypoints where necessary, it can often happen that you appear to be way off course when riding your route. This is because the GPS expects you to be following a straight line between waypoints. Keep following the road and you should eventually come to your waypoint.

Use Satellite Mode
When planning your route, if there's good satellite imagery on Google Maps for the area you are looking at, use it. If you can zoom right in, it's brilliant for: determining whether a bend is a junction or not, determining one-way streets (look at the road markings), accurately placing waypoints, and seeing landmarks which can aid navigation.

Define Your Return Journey Separately
If your route is an out-and-back rather than a loop, define the "out" portion of the journey, save the route, then save it again, but use the "reverse" button on the "GPX" popup window to reverse the order of the waypoints. If you upload these two routes separately to your GPS, it is less confusing than having the GPS display out and back routes superimposed. Note that the "reverse" button on the GPX popup window will change any "R" or "RIGHT" comments to "L", and vice versa.


Known Issues

The following problems are known regarding the initial Beta release of the Marengo GPS Route Planner:
  • Nothing resizes if you resize your browser window. True... although you can resize your browser window, then press reload (BUT SEE BELOW)
  • If you reload the page by using the browser's refresh/reload button, your route is lost. This is actually more by design, but is mentioned to remind you not to press reload when in the middle of a route planning session...
  • Searching / Geocoding doesn't work in many countries. This is because of legal/copyright issues, not a fault of Google or this application. See above for more detail.