Public Lab Wiki documentation


  • 0

GMF-8-An-Ode-To-Maps



By Diana Di Leonardo

Published July 2015 Grassroots Mapping Forum #8. Order online - link forthcoming

I love maps. I love street maps and topographic maps and geologic maps. A well made map contains and communicates a wealth of information. A street map can tell you how to get from point A to point B. A topographic map can tell you how hard it will be to climb that hill. A geologic map can tell you the type and age of the rocks you’re standing on.

You could imagine an infinite number of maps to convey an infinite variety of information.

The goal of the Urban Waters Mapping project is to use aerial photos to map urban restoration sites in New Orleans, and do it in a way that is accessible to everyone. As the name suggests, aerial photos are taken from high in the air. Aerial photos are often taken from a plane, but other less expensive solutions are also possible.

Public Lab has been developing techniques for taking aerial photos using high-flying balloons, kites, and poles. The balloon is the easiest to get up in the air and can go thousands of feet up. Height is important because the higher the camera goes, the more ground area you capture. Kite mapping achieves a similar result as the balloon. With pole mapping, the camera is much lower to the ground, maybe 15 to 30 feet. This approach is great for trying to map areas with a lot of tree cover because you can easily maneuver around and under trees. The drawback is that each photo captures less area of the ground so it takes more photos to map a site, and it is harder to stitch the photos together because there are fewer landmarks in each photo.

Building a pole that was light enough to be easily carried, but sturdy enough to be easily maneuvered was challenging. We’ve ended up with two poles: one made of PVC pipe and another made of carbon fiber. The PVC pole is made of 1 ½ inch PVC pipe and has screw fittings so that it can be disassembled for transport. The carbon fiber pole is a carp fishing pole, no construction required.

The PVC pole is heavier and shorter, but as we would find out during our test of the carp pole, it is less likely to break. The carp pole is much lighter and taller. However it is also more expensive, and can more easily break. On our first test run, we found out that our camera was perhaps just a little too heavy for the smaller sections of the carp pole; the end nearly broke off and dropped the camera in the water!

Public Lab sells kits to get you started with any or all of these mapping techniques.
What would you like to map? Maybe you have a garden in your backyard. You could take an aerial photo of it every week in the summer and watch it start to grow. Maybe you live near the beach. You could go to the beach in the summer and take photos and then go again in the winter and see how the beach changes seasonally.

The possibilities are endless.


grassrootsmappingforum gmf-8

style:fancy