GPS and location shooting

[Ed Richards]

Anyone using GPS for location shooting? I will be shooting in some areas where the map coverage is not much more than a line indicating a road through a marsh. I would like to use GPS to identify where I take shoots, which will also facilitate relocating the site after the next hurricane, when things like roads and landmarks will have disappeared. Ideally I would like a handhelp I can take readings on and then dump these to a laptop to print maps.

[Mike H.]

Ed, I use Google Earth to search locations I want to visit, then transfer Long./Lat. readings from there to my Garmin 60CS via the software that comes with it. There are city maps and topo maps available from Garmin. Haven't learned all the ins and outs yet, since I only got the 60CS as a present at Christmas, but it has been really beneficial. When I'm in the field I have both the topos, a printout of the Google Earth view and the software transferred to the hand held. The hand held also works with a cigarette lighter plug in for my jeep, so that saves the batteries on the drive out to the desert or the mountains or where ever it is I'm going. The overall system has been really great in helping me locate stuff in areas where I had never been and each fork in the unmaintained dirt road looks like the last and is unlabeled. The accuracy factor is something that may concern you - depending on the number of satellites you can pick up, you could be anywhere within a margin of error of 14 feet to 200 feet. I've gone back and forth over the same route using exactly the same two ruts in the road for my wheels and had the resulting GPS map show two different tracks, side by side. On my last trip Monday, I came out in the dark after having photographed at some indian ruins during the last two hours of light and the GPS was fun to use. I also scared the bejabbers out of a bunch of jack rabbits. :-)

[Daniel Geiger]

I use a cheapo GPS (I think it was about $150 about a year ago) and it works just fine. What you want to look for is the ability to connect to a PC (too bad if you want to connect to a Mac). For some GPS units, software is bundled with it, with some it is extra, so watch for that one. But pretty much all can interface with maps that you can then print. If you are in the US, check out REI as they have a nice comparison chart of current models.

[Erik Gould]

I've been using a hand held gps unit lately so I can geotag my images. It's very easy to mark a location in the unit, give it a unique name, and then download it to the computer later. I use this app: http://oregonstate.edu/~earlyj/gpsphotolinker/ to take the data from the gps to my desktop, and then match it up to scans of my images. Then it can be viewed on a google map like this:
http://www.communitywalk.com/map/1799

click on the blue "pins" to see the images. Eventually this map will be full of points, one of my ongoing projects.

I bet this would work great for what you want to do.

no jack rabbits here, but i did see a fox.

[Erik Gould]

Daniel,
I actually do all this on a mac, using a Garmin unit that cost about 200.00. It just needed a cheap serial/pda to usb adapter.

[Conrad Hoffman]

I do something very similar when hunting and photographing NGS elevation benchmarks. I use a Magellan 210 because it has a Windows file structure and interfaces via a simple USB cable. It is also extremely accurate if you can pick up WAAS signals. I also downloaded a nifty map & photo interface, USAphotomaps. Using this, you can download both topo maps and aerial views from the MS Terraserver, and mark your locations. Excellent interface. You can also do a variety of other things, but this is sufficient for me.

Get two pairs of good NiMH batteries for the GPS unit, and a decent charger made for them. Maha makes good ones. With a permanent marker, label them set A and set B. They'll work best if used and recharged as matched pairs. You can then swap them out when necessary and never miss a beat.

Finally, if for some reason you want a more accurate position, or just want to see how good your unit is under differing conditions of signal and satellite pattern, download a copy of SA Watch. This will interface to the 210 and show you the normal wander in graphical form, and will apply sophisticated averaging based on the quality of the fix, to give you sub-foot accuracy under good conditions.

[Kirk Gittings]

Ed,
I can't answer the GPS question but I think where you are going conceptuallw with this project could be very interesting.

[Caroline Matthews]

Check out stephenwillard.com. I think he has GPS coordinates for all his work and his website shows the map.

[Oren Grad]

Then it can be viewed on a google map like this: http://www.communitywalk.com/map/1799

Erik, that's extremely cool. I'll be checking back in the future to see what else you add.

[Ralph Barker]

Ed, I think you'll find the big difference between the various handheld models is the amount of internal memory it has. I opted for the Garmin GPSmap 76CS a few months back, so I'd have enough memory to store more maps (purchased separately) in the unit. Pretty handy. If you want to use it while driving, you'll probably want the optional external antenna.

[QT Luong]

Some of the CS models memory is unsufficent to hold enough data for long road trips. It doesn't even hold all of California. I saw that Garmin introduced recently a new series with removable memory cards.

[Erik Gould]

Thanks Oren. I'm having a show of this work in mid April and I've been holding back the web stuff until then, don't want it getting stale...yet. please do check back then. The geo-tagging stuff is pretty fun, and if you use firefox there are little plug-ins that adapt flickr in such a way that if the image has the Lat and Long. in the metadata, you click on a button and there it is on a google map. cool, esp. considering flickr is yahoo.
which is what i said when i first learned about this stuff.
Oh and btw: My Garmin unit is the eTrex Legend.

[steve_782]

Having purchased my first hand-held GPS in 1992 for logging photo locations, calculating sunrise/sunset, moonrise/moonset; and having worked for three years on a US Army project using kinematic GPS equipment with an inertial guidance system - let me give you a few things to consider.

The accuracy of the unit has to do with the number of satellites available. Depending upon the satellite calendar, that can be anywhere from 4 to 11 - if you have an unobstructed view horizon-to-horizon.

You need three satellites for position and four for elevation. If you're in a canyon, or on a road in the woods with tall trees on either side, this will obstruct your view of the satellite constellation. There is a very good chance you won't have enough satellites available for the GPS receiver to find the position.

The satellite signal levels are about minus 126dBm and minus 135 dBm. That's nearly background noise level. What the units are looking for is a constant 1 pulse per second signal (P3) to locate one satellite and find the L1 and L2 signals out of the background. Once a unit finds a single satellite, it knows the rest of the constellation from its internal calendar and will find the remaining satellites quite rapidly. However, at those low energy levels, don't expect reception everywhere.

Pine tree needles are the exact size needed to act as a natural filter for the L1 and L2 frequencies. You won't get a position in a pine forest, and if you're in a deciduous tree forest when the trees are leafed out - there's a good chance you won't get a position there either.

GPS units are fun, easy to use and can provide valuable information. However, you need to understand their limitations in receiving signals and how the satellite constellation can change rapidly (about a 10 minute time window) causing satellite lock to be lost. If you lose position, just wait about 10 minutes and the constellation should have changed enough to bring more satellites into view.

I currently use a Garmin 60CS. It is far better, smaller, more sensitive, and has way more features than the original Trimble Scout I purchased in 1992.

[Stephen Willard]

As jay pointed out my website does provide GPS location information and maps for all my photographs. The website <A HREF="http://www.stephenwillard.com">[/u] is a prototype site. I did not know if anyone had seen it.

I have also been prototyping an electronic system for managing all my images for three years now. I currently am monitoring about 350 images using this solution. Of those images I have only phot0graphed about 60 of them. It takes me on average about 2.5 years to make the final photograph. I simply revisit the composition continually until finally the light conforms to how I visualized the images many years ago.

All compositions are stored in a database on my desktop, but can be downloaded to a smaller database that resides on my Palm Pilot. I use FileMaker Pro 7 and FileMaker Mobile 7 for my databases that I have designed to fit my needs.

The actual record for each image is created in the field on my Palm Pilot when I discover the composition. At that point a GPS reading and a point-n-shoot photo of the scene is taken. All camera settings, movement settings, tripod settings, site orientation, site location info, and many other things are recorded in the field. The database on my Palm Pilot is a subset of the database on my desktop. All of this information from the field is then merged onto the database on my desktop including the point-n-shoot picture with a push of a button. Furthermore, the GPS way points are also uploaded to my map software so I can actually see exactly where the photograph lives on the map. For example


http://www.stephenwillard.com/documents/photos/Map.jpg




The compositions are illustrated on the map as small blue diamonds. All of the compositions shown above are 4x10 panoramic images and have enormous potential as shown by one of the snap shoots I took while I was there.




http://www.stephenwillard.com/documents/photos/NS-MB-06.jpg


My desktop database has additional fields for characterizing the nature of the image as well as fields for recording all printing information. Some of you may ask why I do this to this extent. In most cases I never get the light I need to take the picture while in a particular drainage. This system consolidates everything about the composition in one place and lets me monitor it over a period of years. Eventually when I final make a real print of the image, I then replace the point-n-shoot image with a scan of the real print in the database.

When I go into the field to revisit a composition, I download the information and point-n-shoot photo onto my Palm and GPS. Sometimes many years go by before I get a chance to revisit, and with my GPS I can find it very quickly and set up my camera in minutes from the information stored in the record in my Palm Pilot. For example


http://www.stephenwillard.com/gallery/imageBig/IP-AP-02.jpg


this image was taken under those circumstances.

This approach has increased my yields in the field significantly. With a database I can query it with many questions, like list all the compositions in a particular area I intend to visit that I have not photographed. Or list all images with a western aspect. It also as helps me in the darkroom by consolidating everything about the image in one place.

I also use my TOPO map software to determine optimal times of the years to visit a composition or site. I use TOPO's ability to build profiles of the land along with sunrise or sunset azimuths to determine when the sun's position would be optimal for shooting a particular drainage or composition. This information is also recorded in the database for each image. I can then query the database to list all images for a particular month that would be best to shoot. At which point I grab my two llamas, my cameras, my camping gear, and enough grub for 5 days and head into the Colorado mountains to do some serious damage!!