Moving maps and vehicles - making the two work together.

During the past year or so, I have been asked several times about what's needed to get an in-vehicle moving map display going. So I thought it was about time I put fingers to the keyboard and published some notes. I welcome any feedback, suggestions or criticisms.

Cheers
brian

What's is a moving map display?

Basically a moving map display is the ability to display, in real time (as you go), your current position on an electronic display. The display can be anything from small grey scale device like a Palm Pilot, right through to a colour laptop. The latter seems to be the most popular due the fact that it's colour and the amount of information displayed is more useful. Most of the points below refer to laptop-based configurations but are equally valid for other display types.

Apart from your current position, most moving map software packages offer additional information, for example, heading, past track information, time of arrival at your next waypoint etc etc.

What you need to get started:

GPS:
Any GPS capable for outputting a NMEA data stream. Most units on the market these days do this but it will pay to check the fine print in the users manual before purchase,

A data cable, usually "serial", to connect your GPS to the laptop. These can also have the ability to connect your GPS to your vehicles power supply saving your GPS batteries. These are sometimes called 'Y' cables, power, GPS and PC connections.

Laptop:
There are many laptops on the market at the moment, and the most common question is what should I buy. Maybe the question should be "What do I need?" The two are different!!

Most moving map software packages need very little compute power. Most of the computing resources needed, are I/O related i.e. the ability to read your maps from disk or CD and display them in a reasonable timeframe.

Most scanned or digitised maps are large, several mega bytes each are not uncommon. For example, Auslig's RASTER 250K series, 1:250,000 maps average 6MB each, about 100 per CD and need 7 CD's to cover Australia. This equates to about 4.2Giga Bytes. Imagine the resources needed to store 1:100,000 or 1:25,000 scale maps for all of Australia.

Probably the most important item is the display, resolution (display detail), size and robustness. Try gently "twisting" the screen and see what happens to the image on the screen. Look also at the construction of the hinges. This is typically the weakest construction point.

One of the biggest drawbacks of most laptops is the ability to read the display in bright light or sunlight. Make sure you try the laptop into natural light before you buy it. Also take a floppy disk or CD with a sample map on it to see how it looks on the laptop. You'll be surprised how different each display looks, colour, definition etc etc.

I prefer a laptop that has an inbuilt CD and floppy disk. Some have external units but there's enough stuff in my truck without having to worry about extra bits.

Not many PC's run off 12v, most use 15 or even 18v internally. In car kits usually cost $200-$300 which is probably better spent on and inverter, 12v DC -> 240v AC.

So in summary:

New Laptops start at around $2000. Second hand around $1000, available via auctions, classifieds and PC stores. Don't forget that you get what you pay for!! Buy a named brand with a good warranty.

You may want to add a scanner to you home PC as well, then there is the local area network to connect your laptop to your home PC, cable modem for faster downloads and ...

Digitised Maps:
This is probably the area most lacking from an availability point of view. There are very few "electronic" maps of Australia compared to the rest of the world. For example, the whole of the USA, in a multitude of different scales, is available on CD for a handful of $$$'s. In Australia, there is only one product, NATMAP 250K that covers the whole of Australia. At $99 for the set of 2 CD's its excellent value. It works out at a little over a 20c per map. This compares to paper based maps at around $8.95 each.

MAPTRAX www.maptrax.com.au can also provide other scale maps scanned and written onto CD or any other media.

Software:
I know of four very good software packages suited to moving map applications. FUGAWI (Canada), GPSS (UK), TrackRanger (Aus) and OziExplorer (Aus), all have their own web site on the Internet. Each have their pluses and minuses but as time goes on their features are becoming more and more similar.

My preference lies with OziExplorer. As the name implies it is written in Australia by an Australian, which is one of the reasons I prefer it. Oh and it does everything that I have needed from a moving map point of view as well.

For all packages look for things like, local datum support (eg Aus Geo 66), ease of transfer of information from GPS to package, speed of loading maps, zooming capabilities, track capacity, route editing. Evaluation copies are available for all packages.

Anything else:

Mounting laptops in a 4WD in particular can be tricky. There are many mounting brackets and arms on the market but make sure you remain legal, i.e. your not supposed to be able to see and use a PC from the drivers seat unless its for Navigation purposes, ie no DVD playing! See www.mobiledesksolutions.com/ for some ideas.

Cables, make sure all cables are secure, safe and the power line is fused.

An external aerial is also useful to increase coverage but that's a subject for another time. See Need one?