See more pictures of balloon aerial photography on Flickr: Balloon Aerial Photography
(See [Balloon Mapping Materials](/wiki/balloon-mapping-materials) for a full list of required materials)
Satellite images can be a great place to start when making a map. But Google’s images are often several years old, and may not be high resolution enough. And isn’t it creepy that they’re taking pictures of you?
With a helium filled balloon you can take your own aerial pictures, stitch them together, and view them a web map like Cartagen or Google Maps. We’re working on a way to trace them and create a PDF to print out.
When you fly your balloon, check for any local regulations - federal regulation say less than 500 feet high is OK, and if your balloon is smaller than 6-feet in diameter and less than 115 cubic feet in volume, you're even excepted from that: [Federal moored balloon regulations](http://www.chem.hawaii.edu/uham/part101.html). Try to stay away from tall buildings because you could scrape against them, but also because the wind currents near them cause a lot of turbulence and your photos come out blurry.
## Materials ##
**Balloons**
Weather balloons can be kind of pricey, starting at ~$12 US dollars in packs of 2 (for 24 dollars total plus shipping) for a three foot wide and 20 dollars plus shipping for an eight-foot balloon. You can compare prices here:
[8 foot weather balloon from Edmund Scientifics](http://scientificsonline.com/product.asp?pn=3041755&cmss=weather+balloon) ($24.95 each)
Buying big party balloons can be cheaper, at ~$6 per balloon, and three or four of them together can lift quite a bit. An added bonus is that if one balloon pops, you have a few more for a soft landing. You can also get them in beautiful red:
[3 foot party balloons on Google Shopping](http://www.google.com/products?q=red%20weather%20balloon) ($4.85 each)
Finally, for the cheapest option, try giant trash bags:
[95 gallon 2.7 mil trash bags](http://www.plasticplace.net/index.php?file=productdetail&iprod_id=341) (roll of 50 for $58.99)
**Helium**
Helium can be bought from Airgas if they’re nearby, or you can ask your local party store where they get theirs. A small tank of 60 cubic feet or so should be more than enough for several flights. 80 cubic feet cost me ~$30. We’re also experimenting with [HotAirBalloons](HotAirBalloons) and HydrogenBalloons but don’t advise that you try this yet. See [this page](http://www.chem.hawaii.edu/uham/lift.html) for some guidelines on lift and different gases.
(Some great documentation on building this rig and using even hot air balloons can be found here: [http://www.paulillsley.com/airphoto/systems/balloons-kites.html](http://www.paulillsley.com/airphoto/systems/balloons-kites.html))
**String**
You’ll need about 400 feet minimum of string. Either fishing line or nylon will do; I used a $3 roll of nylon string which is woven. I worry about the string getting caught on a building so I think the woven stuff is good - it can fray without breaking.
[Video](http://vimeo.com/12292673) of winding 4,500' of string onto a reel with a bicycle.
**Camera mounting**
Your camera will bob and wave around in any amount of wind. I try to fly balloons only in minimal wind (less than 5mph) but if you do have bobbing and spinning you can stabilize things by using a Picavet suspension, which is made from a small wooden X (about a 30 cm across) with rings at each corner, and a kind of complicated string setup. I taped the camera to the center of the X and things improved a lot. See instructions for a Picavet here: [Picavet suspension](http://arch.ced.berkeley.edu/kap/equip/picavet.html)
A simpler rig can be made from a soda bottle: SodaBottleRig
[Cartagen Knitter](http://cartagen.org/maps) can be used to 'knit' the images you've captured into a completed, georeferenced map.