Grassroots Mapping is a series of participatory mapping projects involving communities in cartographic dispute. Seeking to invert the traditional power structure of cartography, the grassroots mappers used helium balloons and kites to loft their own “community satellites” made with inexpensive digital cameras.

Post-oil spill observation trip at Bay Jimmy, LA

July 31st, 2010 by Cesar Harada

Hi, Cesar Harada here, first post and first map using the techniques of Grassrootsmapping.org for LA Bucket Brigade – thanks guys for putting this wonderful DIY technology together. So! In the late morning 22nd of July 2010, Hunter Daniel and myself went to map out of Port Sulphur, on these funky boats :

LABB troops, Seen from the ground, Bay Jimmy LA, After the Oil Spill, 20100722

With 2 boats we took this route (see google map) :

20100722 Grassroot-mapping, Bay Jimmy

I traced this route with my mobile phone Google Nexus One and the fantabulous Open GPS tracker for Android – 4 stars rating!
This is what we could see from the boat, kinda boring :

Seen from the ground, Bay Jimmy LA, After the Oil Spill, 20100722

Soon after I launched a balloon and Hunter a kite out there, kinda exciting :

Seen from the Balloon, Seen from the ground, Bay Jimmy LA, After the Oil Spill, 20100722

we captured nice pictures, here 6 details :

Bay Jimmy, Detail 01, 20100722 Bay Jimmy, Detail 02, 20100722 Bay Jimmy, Detail 03, 20100722 Bay Jimmy, Detail 04, 20100722 Bay Jimmy, Detail 05, 20100722 Bay Jimmy, Detail 06, 20100722

These 6 pictures were made using 270 stills… that was a 12 hours work on photoshop since hugin (an open-source photo mosaic software) didnt do the trick – yet :/ Still working on it to automate the process and spend more time sipping mango juice :)

In addition to what we had a bad GPS trace – my bad, I mean, it is good but I did’nt know where we started taking pictures on that route… Also the GPS time-stamp and the camera time-stamp did not match… So, here is the trick I found:

  • 1. stitch approximately consecutive images with multiple layers on photoshop, when your shape takes shape you may guess where you are on the map. If you only have pictures of water, you can make a great water map … USELESS! BOOO! When your balloon/kite is up  there, make sure it is flying over what you want to see, for us, the coast line – land and water. Wind is crucial, and because of the sun you want to avoid taking pictures when the sun is too high (reflection of the sky in the water).
  • 2. produce a very high resolution map of the area. I didn’t want to do it all manually and I wanted to figure out a hack that would work on every platform (OSX, Windows, Linux), so here we go :
    - find your point of interest on any map system, write down the coordinates of the top left hand corner of the tile you want to produce.
    - go to http://pallit.lhi.is/bigice/bigpic.html , from here enter your Lat and Long (me : 29.468400, -89.911300), the zoom, number of tiles etc… hit “submit”. It will produce a huge map with a static URL. In my case the URL that produced the map (everything is in the URL PHP request) you see here :
    http://pallit.lhi.is/bigice/supergooger.php?lat=29.468400&lon=-89.911300&zoom=18&x_tiles=40&y_tiles=40
  • – now you have this huge picture, you need to capture it from your browser, download the ScreenGrab! add-on for firefox only – but working on all platforms (download Firefox NOW if you don’t have it, you…!). Now, grab that huge picture with the tiny ScreenGrab! button at the bottom right corner of your browser, save as png or jpg.
  • 3. Now, it is much easier to map with a support map! just keep adding layers on photoshop of all the pictures you took, adjusting, stretching, so it matches roughly google maps – you will often find that land shape changes, trees, rivers, buildings etc… that’s very exciting, this is why we are mapping : everything changes !
  • Ok, so now we have this huge empty map :

    Bay Jimmy, empty old google map, 20100722

    That’s another 6 hours work adjusting 700 pics layer by layer on photoshop ; hey, 270 images in 12 hours VS 700 images in 6 hours => see, it is much faster with a support map! We got that :

    Bay Jimmy LA, After the Oil Spill, 20100722 _Desaturated

    Don’t forget to put a scale and cardinal orientation + legal mentions.
    So, under your eyes that’s a 17000 x 17000 pixel map, made of 970 pictures taken at 1000ft altitude, depicting about 5 linear km of damaged coastline. Combining the 6 details views and the general map we could observe that the south side was much more exposed to the spill (more dark brown brrrrr). Using this map we could also establish that on the exposed side, even the inland waterways are strongly affected by the spill : we can use these maps to quantify the surface affected by the oil spill, and the mass of crude attached to the surface coastline. Now even cooler, you can see these maps on google earth, download the KMZ file here (dont worry it is a tiny file – all the content is online). FLY !

    Apart from mapping this catastrophe – which is very useful for scientific study and for lawsuits against BP- why am I personally learning aerial photography? Well, because I am currently designing an oil collecting robot called “protei“.

    Protei.org

    Protei is a sailing semi-autonomous robot with a long oil absorbing tail. Surface oil drifts downwind, so Protei sails upwind, taking and taking, intercepting oil sheens. Imagine many many of these cheap machines out there in the ocean collecting oil :)

    Protei.org

    After some research …
    Protei technical drawing

    I built a steampunk test machine that is pretty promising with a flexible hull front-steering :

    Protei.org

    We are also testing at sea the behavior of a long tail, and same, going pretty well …

    Long test for Protei.org

    See these little balloons on the surface of the water? And this is when aerial photography comes handy : to evaluate the efficiency and behavior of Protei, seeing everything from above helps a lot, I can see the trajectory, the movement of the tail, the interaction with oil.  Also having a highly visible “flying flag” in the sky is amazing to optimize safety and long range communication (flying antenna)… Exciting no? And the challenge is here, millions of liters of crude oil gushing in the Gulf of Mexico, in the Niger Delta, in Latin America, the middle east, in Asia… Protei_Oil_Spill has a busy future!

    Of course, just like grassroots mapping, Protei is developed open-source and collaboratively, so I hope that sometimes soon, Protei will come back to land with a lot of amazing pictures for LA Bucket Brigade and its amazing oil  spill map, GrassrootMapping, Cartagen and Open_Sailing! I received most electronic parts for the next prototype of Protei_Oil_Spill this morning (YAY!), I am building in New Orleans, so if you are around, or if you want to help the project remotely, do get in touch – cesar@protei.org – thanks!

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    6 Responses to “Post-oil spill observation trip at Bay Jimmy, LA”

    1. gwspace Says:

      have you seen autostitch
      http://cvlab.epfl.ch/~brown/autostitch/autostitch.html
      it seam to work on all sorts of odd images?

    2. Jeffrey Warren Says:

      Yes, we’ve tried automatic stitching but it hasn’t resulted in any successful maps yet – most systems assume a fixed camera position (that is, you spin the camera, but don’t move it), rather than what we have, which is all over the place, all altitudes, etc.

      That’s not to say it’s impossible, but I think we appreciate the more participatory hand-stitching anyways, and so far nobody’s demonstrated an automated system which is more effective. Please get in touch if you do!

    3. cesarharada Says:

      I dont know if you guys have tried this, but it remarkable.
      Sony’s Intelligent Sweep Panorama Mode
      http://www.sony.co.uk/article/id/1237476029876
      it works really well.

      There must be some on-the-fly stitching
      http://www.co.palm-beach.fl.us/publicsafety/emergencymanagement/floodawareness/expo/_images/lidar1.gif
      Pretty sure, military have this :)
      But just like Jeff said, if you have a really good [preferably open-source one] Shout !
      Thanks !

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