Best Tile for this area

Satellite images are not perfect: the day will be covered with clouds and you will not be able to see anything, of area was not covered and you will see a white strip.

In order to solve this problem, experts analyze several images of the same area and pick the best "sections" to join them in the best possible image: minimum number of clouds, and broken areas.

This ForestWatchers application tries to replicate this procedure presenting a set of images for the same area and asking the volunteers to pick the best ones. Once all the area is covered, the selected sections will be merged into one final image to procedure with the next steps of deforestation assesment.

Creating Tasks in PyBossa

This web application uses the PyBossa framework in order to manage the tasks and distribute them among the volunteers.

The application has three main items:

• createTask.py script to create the tasks for the application,
• template.html: the web application (it requests a task and loads it for the user),
• tutorial.html: a tutorial about the application (for the moment only one video, we will finish this soon!).

If you want to create your own application you will need the following structure for the application:

• A folder with several raster images of the same area:
  • demo/2012-01-01.tif
  • demo/2012-02-02.tif
  • demo/...

The folder name is the area that you want to analyze, and the raster images should be named according to the following format: %Y-%M-%D.tif.

The script will read the firs raster image, compute sub-areas or sub-tiles to show to the volunteers and create the tasks in PyBossa. The structure of the tasks is the following:

 {
    "info": {
      "tile": {
        "tiles": [
          "2012-01-01.tif",
          "2012-01-02.tif",
          "2012-01-03.tif"
        ],
        "projection": "GEOGCS[\"WGS 84\",DATUM[\"WGS_1984\",SPHEROID[\"WGS 84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]],AUTHORITY[\"EPSG\",\"6326\"]],PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433],AUTHORITY[\"EPSG\",\"4326\"]]",
        "restrictedExtent": [
          -55.908811789016355,
          -10.105939376000004,
          -55.77804053901635,
          -9.989690469750004
        ],
        "bounds": [
          -57.739609289016386,
          -12.430917501000005,
          -53.554929289016385,
          -8.710952501000005
        ],
        "height": 1657,
        "width": 1864,
        "name": "demo"
      },
      "question": "Which is the best tile for this area?"
    },
    ....
  },

The script creates the info section.

Requirements

If you want to use this application you will need a map server serving the tiles. Then, you will have to install PyBossa and follow the documentation to run the software and create the application.