Sunday, March 24, 2013

Hands Off Data Collecting With Huey, Dewey and Louie

A few weeks ago I posted a blog discussing how my organization is testing the newest release of ArcGIS for Windows Mobile 10.1.1.  I've started to use the combination of the ArcGIS mobile software and my Trimble Juno to collect walking trail data on a fairly regular basis.  I call it 'development'.  My wife calls it 'playing around.'

Anyway there are three occupants of my house that think my only job in life is to take them outside and entertain them.  They shall rename nameless, but they each have four legs and a tail.  Whenever they see me putting on a jacket or lacing up my boots or tossing things into a backpack they go nuts jumping around, barking and causing general mayhem.  "It's walkie time!"

Now, I don't mind having them along on a walk or hike.  They are generally well behaved.  Unless they see a cat.  Or a deer, squirrel, rabbit, duck, goose, bird, grasshopper, snail, ant or, heaven forbid, another dog.  Other than that they're fine.  Great company.

But managing three dogs and a data collector is all but impossible unless you're an octopus.  I was in a quandary; how do I take these three amigos along on a data collection hike and get everything done?  Well today I had one of those 'duh' moments, as in 'duh, why didn't I think of this before?'  Just launch the collection job on the Juno, toss it into the zippered compartment in the lid of the rucksack (where it sits up high and the internal GPS receiver should have a fairly good 'view' of the sky), hitch up the dogs and start walking!

Launch the data collection job on the Juno and go!

When I started today's walk I wasn't 100% sure how this would work out.  I've carried other GPS receivers in pockets on the shoulder straps of rucksacks before, but I wasn't collecting data with those units.  As I walked the trail my mind was working, thinking up all sorts of configurations and contraptions I might use to improve signal reception.  By the end of the walk I had myself convinced that what I needed was some sort of pole mounted external antenna.  I had it all figured out in my mind - about 4' of quarter inch PVC with a metal plate epoxied to one end and a magnetic patch antenna (which Trimble makes for the Juno) stuck to that, with the antenna cord running down the tubing and connecting to the Juno inside my rucksack.  I could lash the PVC tubing to the side of the pack using the compression straps.  Absolutely, perfectly Rube Goldberg-esque!  Why it was so clever I'd be the envy of all the neighborhood GPS data collecting kids!

Rides nice and high in the pack where signal reception is pretty good!

At the end of the hike I pulled the Juno out of the bag and realized I didn't need all the fancy gadettry I was dreaming up.  The Juno did just fine collecting data while sitting snugly inside the rucksack lid.  It's not a perfect setup by any means; the GPS signal still has to penetrate the bag material and my big fat noggin' blocks a lot of the signals, and it's impossible to stop collecting streaming GPS data to collect point data.  But for hikes like these where I'm just after trail alignments it works fine.  The Juno isn't a survey-grade instrument anyway so some GPS track shift is to be expected, particularly under heavy tree canopy.

"Hey, we really like this data collection thing!"

So how did we do?  Not bad.  I need to clean the data up somewhat and I know that in the future if I'm set up for GPS data post processing I'll get better accuracies, but for now it'll work.  As was said in that classic movie about chronic over-achievement, "That'll do pig."

 

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