GPS with Laptop

[scoundrl <scoundrl@vnet.net>]

The following is a report I have written about my experiences connecting 
my TP755CD to a GPS receiver and using DeLorme's MapExpert software to 
display a continually updated map in my car.  The report is long, but 
quite ontopic for this group.  I have "mined" this group for a number of 
questions I've had as I explored the system and the report might be of 
interest to any of you who might be considering such a system.

The following is a report about using software by DeLorme Mapping with a
laptop computer (with CD ROM) and a Global Positioning Satellite receiver
to display a continuously updated map in a vehicle.  The DeLorme map
covers all roads, streets, streams, political boundries and most other
common features in 15 levels of detail, down to a level of about 1" = 1/10
mile in the USA.  The map automatically centers as the vehicle moves,
leaves "breadcrumbs" and can be modified by the user to show other
features, using "overlays."  Having just completed a 2,500 mile trip using
the setup in our van, I am writing this report for anyone interested in
trying it for themselves.  The text of the report follows: 


GPS and a Map In Your Car!
^^^^^^^^^^^^^^^^^^^^^^^^^^

There are a few things in this world that fall into the totally,
absolutely, unquestionably neat category.  Friends who know me well, know
that I seldom go off on tangents about things unless they are really
unique or solve a specific long-standing problem.  The system I recently
assembled from off-the-shelf components fits that bill and I want to share
with you how I did it, how it works and how it can be used. 

EQUIPMENT and SOFTWARE

The components necessary for having a continually updated map in your 
vehicle are as follows:

MapExpert 2.0 CD ROM by DeLorme Mapping (207) 865-1234

    This CD Rom is a street atlas of all streets, drives, roads, lanes,
creeks etc. in the continental USA, including Alaska and Hawaii.  A
simpler version of this incredible good software is sold at most software
stores as Street Atlas 2.0 or Street Atlas 3.0 by DeLorme.  MapExpert is a
superset of Street Atlas 2.0, in that it includes a large number of
additional tools, such as the ability to locate a place by its longitude
and latitude and the ability to add overlays.  As far as I know, MapExpert
is only available directly through DeLorme.  More about it later-

GPS Link II software by Delorme

    This additional software is on a floppy and "wraps around" the 
MapExpert software.  It takes an industry-standard signal that is sent 
out by a GPS receiver and feeds it to MapExpert to "center" the map on 
the generated longitude and latitude, leave breadcrumbs as you travel and 
control several other features.

Eagle Accunav Sport GPS Receiver with NMEA-183 output
  
     We had a boat which used this handheld GPS receiver.  When we sold
the boat, I kept the reciever.  The Eagle Accunav has many more features
than are needed for use with the DeLorme software, since it is also a
competent stand-alone product for boaters.  Virtually any other, less
expensive, GPS receiver could be used, provided that it has a connector on
the back that outputs the industry-standard NMEA-183 signal and an antenna
that can be detatched and located on the vehicle's dash for a clear view
of the sky.  The NMEA port is quite common, since most GPS receivers now
use it for input of differential Loran signals and/or output (the
NMEA-183) to other devices. Most of the handheld receivers are small
enough to fit easily in a shirt pocket nowdays. 

     Eagle sells a cable that is has a plug matching the receiver on one
end and with bare wires on the other.  Eagle's owners manual specifies the
use of each of the wires, and it is necessary to only use two of them. 
These two are soldered to a standard DB-9 serial connector from Radio
Shack, which connects to the laptop.  Both the GPS manufacturer and
DeLorme provide excellent and clear instructions on how to do this. 

Laptop Computer with CD ROM drive.

   My own laptop is an IBM Thinkpad 755CD.  The key components for a
system, however are merely 1) a 12 volt laptop machine, 2) a connected
internal or external CD ROM drive for the MapExpert software, 3) a serial
connector on the laptop and a power supply from the vehicle for the laptop
and the GPS receiver.  While both COULD be run from internal battery
power, it is desirable to supply them with a continuous 12 volt power
source.  An active matrix screen is a nice feature for the additional
brightness in a vehicle. 

ASSEMBLY and SETUP

AI began my "great adventure" by ordering the software from DeLorme and
installing it on the laptop.  Both the MapExpert CD and the GPS Link II
installed on the first try and I spent a day just playing with the
MapExpert software alone.  I had also ordered the NMEA connecting cable
from Eagle and it arrived in a few days as well.  A trip to Radio Shack
for the DB-9 female plug and ten minutes at my desk connecting the two
wires from the cable to the plug were all it took to complete the
assembly.  The assembly of the connector had seemed intimidating, but
turned out to be anticlimactic. 

When I connected the receiver to my laptop and fired the GPS Link II
software up, however, I got an error message on the screen that there was
no connection to the serial port!  After a moment of panic, I read the
laptop's manual and learned that I had to select the serial port, activate
it and do several other gyrations on the Thinkpad.  Having done this, I
STILL had no connection. A call to IBM's support 800 number resulted in
over an hour of "hold" and no assistance.  Fortunately, I had made the
correct changes, it turned out. 

I then gritted my teeth and e-mailed DeLorms's support hotline.  DeLorme 
advertised voice, fax and e-mail support.  What I recieved was an 
almost-instantaneous response from DeLorme's support staff suggesting 
several changes to the GPS Link II software. I made the changes, but 
still had no luck.  

I e-mailed them again and AGAIN received a reply within minutes!  The
suggestions were to 1) change the baud rate from the default values in
their software and to 2) GO OUTSIDE and try it.  There I stood in freezing
rain with the laptop under visqueen.  Suddenly, the "No Serial Connection"
message changed to an "Excellent 3-D Quality"  message.  The screen with
the map on it flashed and I was looking at a high resolution map of the
street in front of my own home, with the cursor centered in my driveway! 
What a thrill! 

I found I could "zoom" in or out in 15 steps from a now-centered map of
the USA, down to a street-level detail map.  Always, the map stayed
centered (can be turned on or off) on where I was.  At resolutions of 14
or more, even the exit and on-ramps of highways are visible! 

I took the setup to my pickup truck and placed everything in the seat.  
Almost immediately, I began to get error messages again.  It seemed that 
the GPS receiver must have an unobstucted view of the sky to maintain 
contact with the 5 most visble satellites!  

A call to Eagle ordered their remote antenna cable.  This cable is about 
3' long and permits you to dismount the antenna from the GPS unit and to 
use it remotely- as on the dash of a vehicle- so that it gets an 
unobstructed view of the sky.

With the system now working, I drove around town.  As the vehicle moved, 
every six seconds (adjustable) a little "breadcrumb" would be added to 
the map as an overlay, showing where I'd been.  I could also add little 
windows that could show altitude, speed and direction and the time.  I 
cannot describe the fun of seeing a map unfurl as you drive (yes- I was 
careful and stopped to make changes in the setting).  It was like having 
a navigator in the car with SIXTEEN maps of different scales and 
complexities that were updated for location every 6 seconds!  

The next step was to try figuring out how to put everything neatly in our 
van for an anticipated vacation, but to still have the individual components 
available for other use and to make it readily removable for nightime 
when the van would be unattended.  

Our van is a 1996 Chrysler Town and Country and has a cupholder in the 
center of the dash down low.  I first traced the bottom of the Thinkpad 
onto a piece of 1/4" plywood and then cut it to shape.  The front of the 
plywood rested on the extended cupholder and the rear rested on a single 
2" wide "Leg" made out of the same plywood that rested on the floor of 
the van.  To secure the plywood base in the cupholder, I merely glued 
blocks of wood to the bottom of the plywood that fit into the cupholder 
sockets and held everything securely.  The leg was fastened to the base 
with screws, glue and a block of wood for reinforcement and was stained 
to match the trim of the van.

I purchased some Velcro from the hardware store and placed two 4" strips 
at the front and back of the Thinkpad, with corresponding strips on the 
top of the plywood base.  These worked out wonderfully to hold the 
Thinkpad securely, while permitting easy removal for other uses.  I was 
sure to leave room behind the Thinkpad for its power connection and the 
serial connector.  

Another piece of Velcro on the leg of the platform permitted me to mount 
the GPS receiver where I could easily reach its on/off buttons, while 
keeping it low and out of the way.  A hole in the leg was necessary for 
the NMEA/serial cable to pass through.

The IBM Thinkpad uses a fairly large "power brick" for 115 volt power, and
the IBM Car Battery Adapter is fairly expensive at $120.  Since
electronics are included in the external power supply, merely getting a
cigarette lighter plug at Radio Shack won't work for the IBM.  For many
OTHER laptops with CD ROM, however, it will work just fine. 

Instead or paying for the separate Car Battery Adapter at $120, I opted to
buy a power inverter that outputs 115 VAC with 150 watts continuous power
for just under $50.  The inverter plugged into the cigarette lighter and
was fastened to the other (hidden) side of the plywood leg with velcro and
the power brick for the thinkpad was then fastened to it. It worked just
fine, but I later switched to the IBM Car Battery Adapter to save on the
bulk and weight of the inverter.  I also soldered a lead to the 12 volt
input to the Car Battery Adapter that neatly ran to the GPS receiver to
supply it with current from the vehicle as well, eliminating a second 
cigarette lighter connection.

All cables were bundled and tied to the platform using tie straps to keep
them neatly in place and to prevent breakage from excess flexing.  The 2" 
square GPS antenna was held in place on the van's dash with a 3/4" square
of velcro.  To remove the entire system only took a moment to undo the
antenna and to stick it to the top of the laptop (another velcro patch),
to pull out the cigarette lighter plug and to lift the assembly out of the
cupholder.  It fit neatly under an arm to take into hotels along the way. 
To use the laptop (such as logging onto the 'net or Prodigy) from the
hotel room, pulling out the power and serial connectors and lifting it
free from the platform's velcro strips was a snap. 

USING THE SYSTEM FOR TRAVEL

One thing that sets the MapExpert CD software apart from its sister
program, Street Atlas 2.0 is the ability of the user to create overlays on
the map and to store them for future use.  The overlays can be combined,
such as layering different marked sheets of clear acetate over a map at 
different times.

Using my desktop machine and other software, I planned our trip to 
Florida out and planned the route we'd take.  This information was then 
placed on a single overlay on MapExpert using text, symbols and arrows.  
Using some of its other tools, I also located where we'd be staying at 
nights and located the hotels locations, even!  It was easier to do this 
ahead of time, since a large monitor, good mouse and fast machine make 
the job go much smoother.  The overlay was then stored and copied to the 
laptop's hard drive as well.

In using the system, we soon learned that the three most useful scales 
for travel were 1"=5 miles, 1"=2 miles (to get crossroad names) and 
1"=1 mile for on-ramp and off-ramp information.  The highest levels of 
detail, such as 1"=1/2 mile and 1"=1/10 miler simply were TOO much detail 
for general highway travel.  However, the two highest resolutions DID 
prove very helpful when we took a wrong turn once and ended up on the 
back streets of Miami Florida.  Then, without any assistance, we 
immediately located the next on-ramp to the highway and navigated about 2 
miles of city streets, with turns, to get back onto the highway!  That 
alone made the system worthwhile, in my opinion!

CONCLUSION

I think that the software and support of DeLorme are some of the finest
examples of what good people with good tools can do today.  The software
is above and beyond anything I ever imagined was available for the "common
man" today and has to be seen and used to appreciate.  DeLorme's support 
is instantaneous and highly knowledgable- in keeping with thier products.

Connecting the GPS to the laptop was easy.  Installing the software was a 
no-brainer and the debugging was not bad.  I am glad that I didn't need 
to use IBM's non-existent support, since you can easily grow old waiting 
for a person to answer.  The Eagle receiver had an excellent manual and 
the two cables I ordered were handled promptly and correctly.

DeLorme recommends, and even sells, GPS receivers and CD ROM add-ons to 
facilitate thier software, but I suspect that mail order houses can 
provide the same materials for less money.  I am not connected with 
DeLorme in any way and paid retail for the software I purchased, so my 
comments are unbiased.   



Thomas A. Gauldin       Here's to the land of the longleaf pine,
Raleigh, NC             The summerland where the sun doth shine,
BSRB45A on Prodigy      Where the weak grow strong and the strong grow great,
FAX (919) 676-1404      Here's to Downhome, the Old North State.