00:01Well I'm here to talk about something not quite so glamorous and it's not sunshine. Accuracy.
00:06And accuracy is important and that's why you need volunteered geographic information.
00:13Doesn't sound quite right, does it?
00:14What's a surveyor doing talking about accuracy and a bunch of guys running around with cell phones collecting information?
00:20Well if we believe the currency and correctness and completeness are forms of accuracy, then we all need VGI.
00:26We need accurate information to get the efficiencies out of our systems.
00:31We need accuracies to expand the uses.
00:33And we need accuracy just to get the right answer.
00:36So accuracy is improving at a rapid rate in all forms of data.
00:41So let's look at a parallel.
00:45How accurate is this?
00:46Eons ago you want to meet for a beer at 3:00.
00:49This is what we had.
00:50Good to about 20 minutes on a sunny day and in the daytime.
00:56And not everybody had one.
00:58So we put them on the walls of public buildings and churches, so it kind of brought us together little bit as a community.
01:02We're beginning to synchronize and get some efficiencies from time.
01:06And as technology progressed, we built pendulum clocks.
01:09Want to meet for 3:00 at the community pub?
01:14Even multimedia, had chimes, right?
01:16So we really gained a lot of efficiencies through this synchronization.
01:22And we could even meet after dark, right, because it worked after dark.
01:27At this same time, for a couple centuries from about 1500 to 1750...
01:31...the Europeans were crashing ships into the east coast of the Americas, and they were losing thousands of ships.
01:37They couldn't calculate longitude.
01:39Actually, Sir Isaac Newton thought that longitude was not a calculable thing, it's a function of time.
01:46But pendulum clocks were fixed.
01:48The most important invention at the time was the Harrison clock.
01:51This is the H4 that's revolutionized navigation.
01:54It revolutionized time.
01:55It allowed us to take time from being fixed and we could...it was now portable.
02:00This actually ended up becoming wristwatch and all kinds of things.
02:02Technology was going from a pendulum to a clock spring.
02:10The next change is the Casio watch.
02:14This is when we went from a mechanical device to a digital device.
02:19It's hard to think about any piece of electronics right now without a clock on it.
02:24It's just a little chip.
02:25It's just a little piece of electronics, faster, cheaper, better, smarter.
02:28Just the whole way electronics goes.
02:32GPS is the Casio watch of positioning.
02:36Right now, we can do subcentimeter worldwide in real time.
02:41Devices are getting smaller.
02:42They're getting cheaper.
02:43They're getting easier to use.
02:45We're attaching GPS to everything.
02:48It's in our phones of course.
02:50Nokia owns all the patents to make our phones good to 10 cm.
02:56What happens when the accuracy of the phone is better than your basemap?
03:02What happens when everybody's phone is better than your basemap?
03:06What do we do?
03:07We can't remap.
03:09It's too expensive and we don't have the time.
03:12So what do we do?
03:14We need to build incremental improvement of accuracy into our daily workflows...
03:19...and using all different types of data, lidar, imagery, even volunteered geographic information.
03:25So let's take a look at an example.
03:28County does a new ortho project, 6-inch positional accuracy, 3-inch pixels.
03:32Pretty good stuff.
03:34Parcels don't overlay.
03:35We're not going to go remap the parcels.
03:37But we can harvest the measurements from those parcels and build a measurement network...
03:41...to improve the parcels and synchronize them with the orthos.
03:46We can actually take the information from that synchronization and use that to control the accuracies of other features in GIS.
03:53We have time/date stamps and we have feature-level metadata.
03:57So we have a lot of tools in the toolbox to build these workflows to keep ahead of the improving accuracy.
04:06Alright, now let's look at another example here, everybody's favorite, sewer manhole.
04:11Who has the most accurate information on this manhole?
04:16Well the engineer has the rim to about a hundredth of a foot which is about an eighth of an inch...
04:19...so you don't go thump, thump when you drive over it.
04:22He also has the inverts or the flow lines so things flow the appropriate direction.
04:27Now the public works director has a mapping location, and he's got inspection reports, and he's got construction specifications...
04:34...he's got all kinds of information on this manhole.
04:38But who really has the most accurate information on this manhole?
04:41The manhole cover was stolen.
04:45This is a hazard, it's a liability, and it needs to be fixed immediately.
04:51Guy walks out his front door, picks up the newspaper, and takes a picture with his GPS phone.
04:58Who has the most accurate information on that manhole?
05:03So as GIS professionals, we need to think about aggregating all types of data together...
05:08...and we need to think about our workflows to increase to our daily work the accuracy of our data.
05:16It's not authoritative data versus volunteered geographic information...
05:20...it's authoritative data and volunteered geographic information.
Who Has the Most Accurate Information?
Brent Jones, Esri surveying and engineering manager, talks about building accuracy into all our workflows and how to gather the most recent and accurate data.
- Recorded: Mar 6th, 2011
- Runtime: 05:26
- Views: 14339
- Published: Mar 28th, 2011
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