Best GPS units for the job in the field?

June 1, 2008 10:20 AM

What is the best GPS unit to buy for my fieldwork, that would ideally display a list of homes to be mapped in a spreadsheet format and allow touchscreen entry of information into the spreadsheet (coordinates, consent obtained [yes/no], why home was unable to be mapped [drop-down menu])? Does this type of interface exist for GPS units?

I am headed to Thailand for some fieldwork for my research, and will need to hire village health workers in a rural area to GPS map the homes of approximately 3000 individuals (geocoding in Thailand is not possible, I don't think).

I need to buy 2 GPS units but don't know much about the technology and what units and features will help me get the job done most efficiently and simply. I'm hoping that if I describe what I would like to be able to do, you guys may have some suggestions for good units to buy.

The village health workers will have a list of addresses and names. They will then physically locate the homes, talk to the residents of the house, and get consent to GPS map the house. Ideally, the list of addresses and names could show up on the GPS unit as a spreadsheet and they would be able to tap a screen to document that consent was obtained and again to record the X- and Y- coordinates. If the house was not able to be mapped, they would be able to select from a drop-down menu to explain why they couldn't map it (no consent, couldn't find house, etc.). After they were done mapping, the list could be downloaded and linked to existing excel files with clinical information.

Can this be done? I know that Palm Pilots, for example, have some flexibility for use in field work (administering questionaires, etc.) but don't know about these types of interfaces with GPS units. Any guidance you may provide would be very helpful, I appreciate you helping a newbie out!

posted by xholisa13 to technology (13 comments total)

You can get a little battery powered bluetooth GPS device that can talk to a modern palmpilot wirelessly. Also Garmin was selling a compatible PalmPilot with in-built GPS - not sure if they still do. Should also be a bunch of Windows Mobile/Windows CE (Whatever it is called now) devices that might suit you.
posted by schwa at 10:55 AM on June 1, 2008

I have a five-year-old Garmin iQue 3600 which might be able to do what you want. It's a Palm device with built-in GPS. You could make a new contact with the location set to your current location, and add in whatever notes you want. Not sure about drop-down menus, but since it's a fully-featured Palm OS device, it must be possible to write a program that does that.

The iQue 3600 has really terrible battery life, but GPS devices have come a long way in five years.
posted by Dec One at 11:07 AM on June 1, 2008

One additional question - what store would have the most knowledgeable staff as I seek to follow up on your recommendations?
posted by xholisa13 at 11:10 AM on June 1, 2008

asus eeepc901 when it comes out
posted by complience at 11:29 AM on June 1, 2008

If you need something rugged and tightly controlled for data collection, I think you want something like Esri's Arcpad, which you can buy bundled with different hardware depending on your needs. Another alternative along similar lines would be the Thales MobileMapper.

Alternatively, if you don't want to muck about with custom software, those little Bluetooth dongles also connect to laptops and tablet PCs. You should be able to use a standard spreadsheet program, and feed in GPS data using fairly common software. (GPSy comes to mind on the Mac side, but I know many options exist.)
posted by j-dawg at 11:32 AM on June 1, 2008

A Nokia N810?

It's an Ultra Mobile PC (UMPC) that runs linux and includes a GPS receiver. Touch screen. Should be easy to write up an application that does what you want (drop-down menus, spreadsheet).
posted by notyou at 11:34 AM on June 1, 2008

Just be aware that there is some margin of error when you pull GPS data into GIS -- maybe the interface is better than it was when I was using pretty high-end equipment a few years ago, but I could take a point standing on one side of the road and then pull it into ArcView/Map and it would be on the other side of the road -- For your sake, I hope the technology is beyond this and the layers blend more seamlessly --

I don't know how close the house will be in this village, but it might be an issue.
posted by nnk at 11:39 AM on June 1, 2008

that's "houses." Sorry.
posted by nnk at 11:40 AM on June 1, 2008

Just be aware that there is some margin of error when you pull GPS data into GIS -- maybe the interface is better than it was when I was using pretty high-end equipment a few years ago, but I could take a point standing on one side of the road and then pull it into ArcView/Map and it would be on the other side of the road -- For your sake, I hope the technology is beyond this and the layers blend more seamlessly --

No, that's just the margin of error built in to civilian GPS units to keep you from building your own cruise missile.
posted by b1tr0t at 12:27 PM on June 1, 2008

No, that's just the margin of error built in to civilian GPS units to keep you from building your own cruise missile.

Bill Clinton scrapped that 8 years ago. It is unlikely to return.
posted by Olli at 3:53 PM on June 1, 2008

This depends on your budget, of course, but an off the shelf solution is a mobile computer running windows CE, a GPS unit (either cabled or bluetooth), and then software: ArcPad and ArcView, both from ESRI, the industry standard (but most expensive) GIS. Here's an example of what we put together some years ago. At the time, off the shelf solutions were fewer and farther between. What you describe sounds like a much easier problem. You might want to hunt around on the esri site for ArcPad applications and suggested hardware.

Both posters are wrong about the source of the inaccuracy. It is because the GPS accuracy is on the order of ten or twenty meters (within the US, a system called WAAS broadcasts a correction that gives you accuracy to about 5 meters). It is not because of intentional disabling of the system. Selective availability was the name for the intentional introduction of random errors in civilian GPS equipment. It was turned off years ago. If you need sub-5 meter accuracy, either you will pay thousands of dollars for real time DGPS or you can set up a base station and post-process.

If you need to post-process, your best bet may be to get equipment and software from Trimble that is already set up to do such things. They have software and hardware that interfaces nicely with ArcPad, ArcGIS and other GIS apps. Here is a good overview of equipment, software and procedures for GPS and post-processing. Once you get into survey quality hardware, the costs go way up, but you can lease the equipment for the duration of your project.
posted by bumpkin at 3:58 PM on June 1, 2008

Both posters are wrong about the source of the inaccuracy. It is because the GPS accuracy is on the order of ten or twenty meters (within the US, a system called WAAS broadcasts a correction that gives you accuracy to about 5 meters).

Within Thailand he may be able to use MSAS which would bring accuracy to around 3 metres.
posted by Olli at 4:51 PM on June 1, 2008

Thanks all! I appreciate your comments. After considering the options, I decided the most cost-effective and simple option would be to invest in the Garmin GPSmap 60CSX (on sale for $300) and then simply have the field workers record the waypoint number on a paper spreadsheet. Should be easy enough. Thanks again!
posted by xholisa13 at 1:58 AM on July 2, 2008