In a few days I will be heading towards McAllen, Texas and across the McAllen International Toll Bridge into Mexico with my school bus packed full of household belongings.

Google Maps takes a very reasonable route from Mountain View CA to McAllen TX, basically Hwy 101 to I-5 to LA, then I-10 across the country to San Antonio TX, then Hwy 281 to McAllen. (I simplified this somewhat). Google lists the distance as 1948 miles.

My Garmin Nuvi 360 shows similar routing (hard to compare, the Garmin seems to note every exit and crossroad in its instructions) but shows the distance as 1596 miles.

I cannot believe that Garmin plotted a route that was 350 miles shorter while still using Hwy 101, I-5, I-10, and Hwy 281. Or that Google somehow added the miles up wrong and came out 350 miles longer.

Who do I believe?

Anybody want to try their own GPS plot from 300 Tyrella Street in Mountain View, CA, to 1023 International Boulevard, Hidalgo, TX and see what they get?

tanstaafl.

Multimap/Bing gives the Google answer of roughly 1900 miles.

I'll bet it's a question of data set resolution. The longer answer is more likely to be true.

How many miles long is the coast of Britain?

Unlikely. Both are measuring in miles/tenths-of-miles, and a difference of 18% would be more than data set resolution would provide.

I have great faith in Google's distance measurements. I have mapped bicycle rides on Google, then compared the distances against a calibrated odometer on my bike that measures to the 1/100th of a mile, and found errors of less than 100 feet in a 20 mile ride. That's 99.9% accuracy, a far cry from the 18% difference between Garmin and Google.

The GPS in my Honda shows a distance of 1996 miles for the trip, but I haven't checked to see the actual route it chose, so it may be Apples and Oranges comparison.

tanstaafl.

Yow! Can't answer your question, but very cool to hear that the bus is rolling. I would greatly appreciate it if you can post some pics along the way, let us know how it is going. Oh, and once you have settled in, remember to send an email that it is OK for me to come visit

Just finished reading Phillip Caputo's latest book _Crossers_. Maybe not exactly what you want to be reading as you roll across the bridge, but a fantastic book. Mexico has its problems (dang, some huge problems) but I will be following in your tracks, with any luck. A country with some big problems but a big heart.

Vaya con Dios.

Firstly it appears to be Tyrella Avenue (not Street).

TomTom on my WinMo phone said it couldn't find a route in the direction you were travelling which was a bit strange. Google seemed to have the exact same problem.

Running it reverse from TX to CA gave 1949 miles on Google and 1984 miles on the TomTom so near enough for all intents and purposes and within a couple of percent which is about as good as I'd expect.

Congrats! I'm not too far behind you. Currently planning to roll through Mexico en route to Belize in late January.

Some questions for you:

What are you using to map your route through Mexico? Do you have a GPS with accurate maps of Mexico that can do turn-by-turn directions? What type of place should I be looking for for overnight stops? Is fuel readily available for a vehicle that only has a range of 250-300 miles (perhaps even a little less when loaded and pulling a trailer)? Out of curiosity, why McAllen instead of Brownsville or Laredo?

Did you *read* that linked article about the coastline of Britain?

It's not about whether or not they give you the answer in tenths of miles or not. It's about how much detail they measure in the crinkly bits.

Although I agree that 18 percent seems kind of high on the face of it, if the Garmin device is trying to save ROM/RAM space by not mapping the crinkly bits very tightly, you could get quite significant differences.

While all that it true, it is perfectly possible to not store many crinkly bits on the device, but to still report distances of routes as if you had. The device doesn't just have to store the vectors that represent the road, it can also store the length of the road between two points, even if it has relatively little detail on the actual route the road takes.

My Garmin has Mexico Maps from these folks. Much better than that, though, is that the man we bought our condominium from is meeting us at the border and will ride with us to Ajijic. He has arranged for me to hire a driver who is a professional used to handling big rigs and dealing with Los Transitos, the Mexican highway patrol. That school bus is a MONSTER to drive, 5-speed manual transmission with 2-speed rear axle, no power steering, and a turning radius comparable to your neighborhood Costco parking lot. We will actually have to block off the main road through Ajijic so we can back-and-fill to make the right-angle turn onto Colon street.

McAllen was chosen over Laredo on the recommendation of the driver. We will travel about 100 miles further overall, but will be on better roads and avoid the worst of the mountain passes. We will be on toll roads the whole way, figure about $300 in tolls for the two vehicles (the bus and SWMBO's Honda) but the money spent is well worth it in terms of easier passage, available services, and peace of mind.

Fuel range isn't a problem. At current prices, the bus holds about $225 worth of gas (75 gallons) and will go nearly 600 miles on a tank. The Honda only holds $30 worth of gas, but it will go 400 miles. We will only have to refuel one time in Mexico before reaching our destination.

As for accommodations... I have no idea. That's SWMBO's department. She will be ranging ahead (she won't want to go at the bus's snail pace) and making the arrangements. I will probably sleep in the bus as a security measure. We'll only have to make one overnight stop, in any case.

tanstaafl.

I wasn't going to question your driving or interpersonal skills by asking "Are you driving?", but I am guessing this might be the best money you ever spend. Very cool that you already have an agent in place.

Might be a little late, but do you fancy a pint/mini meet pint with the locals before you set off? (not *immediately* before, obviously )

Would be good to finally meet you!

Hugo

Actually... probably not, Hugo. We are absolutely buried with the packing up and are facing an implacable deadline by which we MUST be in Guadalajara to pick up SWMBO's brother at the airport.

It isn't the packing up so much as the sorting through. We are downsizing by a factor of six in terms of square footage (counting the Alaska home and the California home) and so much stuff has to be disposed of. For me, it's no problem. I've got two bicycles, a computer, and a large duffel bag full of clothes, the rest (what little there is) I don't care about. Oh, a few odds and ends here and there, an empeg or two, a nice camera, bits and pieces. SWMBO, on the other hand... the duffel bag that contains all of my clothing wouldn't be big enough to hold her shoes. The problem is, her stuff (in contrast to mine) is nice $tuff that she can't bear to part with. Sigh...

Oh, we have met on two occasions. The first time was when Tony Fabris and I drove down in the ShoWagon to wherever it was (San Francisco?) for a mini-meet where you were giving out tuners for beta testing. The second time was at the empeg meet in Amersfoort in 2005.

Thanks very much for the invite/suggestion, but I just don't see a way to make it happen.

tanstaafl.

Thanks for the info. I'm still in the planning stage for my trip, so it'll come in handy. I too have a guide that's flying up from Belize to make the drive down with me. Seems to be the way to go.