Draft workflow for loading FORMA hits to CartoDB from GEE

draft-gee.py

import pandas as pd
import forma
import ee

from bbox_tiler import bbox
from globalmaptiles import GlobalMercator

def coordsToTiles(lon, lat):
    # Convert the supplied latitude and longitude coordinates to
    # mercator tiles at zoom level 16, ready for upload to CartoDB.
    mercator = GlobalMercator()
    mx, my = mercator.LatLonToMeters(lat, lon)
    tminx, tminy = mercator.MetersToTile(mx, my, 16)
    return tminx, tminy

def grabPixels(img, coords):
    # Accepts the FORMA alert image and the coordinates of a polygon
    # and returns a list of lists, one for each pixel.
    polygon = ee.Feature.Polygon(coords)
    coll = ee.ImageCollection.fromImages([img])
    return coll.getRegion(polygon, 250).getInfo()

def convertEntry(x):
    # Convert the GEE output for each pixel into a dictionary entry
    # that will eventually be converted to a Pandas data frame row;
    # keys are the variable names.
    x, y = coordsToTiles(x[1], x[2])
    return {'x':x, 'y':y, 'z':16, 'p':'first-half 2007 alerts'}

def tileToPandas(img, tile):
    # Accepts a FORMA alert image and the tile object and returns a
    # Pandas data frame of the results
    print tile
    pixels = grabPixels(img, tile[2])
    data = map(convertEntry, pixels[1::])
    return pd.DataFrame(data)

def genResultCSV(filename = "/mnt/hgfs/Dropbox/forma_hits.csv"):
    # Generate a CSV of the results for the entire ecoregion
    img = forma.calcChange(40160, '01/17/2007', '12/31/2007')
    UPPER_LEFT = [99.53064,3.25346]
    LOWER_RIGHT = [106.23779,-4.31029]
    tiles = bbox.mk_tile_bounding_points(UPPER_LEFT, LOWER_RIGHT, 20)

    res = map(lambda t: tileToPandas(img, t), tiles)
    coll = pd.concat(res, ignore_index=True)
    coll.to_csv(filename)

    return coll