New computed bounding box code

[stansmith907]

I found an issue with improperly computed bounding boxes when one geometry was fully contained in the eastern hemisphere and another fully contained in the western hemisphere. I think this new code should work in all cases, please review and let me know if you see a problem.

    # compute bounding box
    def self.computeBbox(aGeo)

        # find all the eastings (x) and northings (y) in the GeoJSON object
        aNorthings = []
        aEastings = []
        aGeo.each do |hGeo|
            unpackGeometry(hGeo, aNorthings, aEastings)
        end

        # find most north/south points
        north = aNorthings.max
        south = aNorthings.min

        # find most east/west spanning the meridian
        eastM = aEastings.max
        westM = aEastings.min

        # find most east/west spanning the anti-meridian
        positiveEast = []
        negativeEast = []
        aEastings.each do |east|
            negativeEast << east if east < 0.0
            positiveEast << east if east >= 0.0
        end
        eastAM = negativeEast.max
        westAM = positiveEast.min

        # if eastings are all positive or all negative no meridian was spanned
        if positiveEast.empty? || negativeEast.empty?
            east = eastM
            west = westM
        else
            # choose which meridian was spanned based on smaller edge-to-edge distance
            distanceM = eastM - westM
            distanceAM = (180 + eastAM) + (180 - westAM)
            if distanceM <= distanceAM
                # this spanned to  meridian
                east = eastM
                west = westM
            else
                # this spanned tne anti-meridian
                east = eastAM
                west = westAM
            end
        end

        bBox = {}
        bBox[:westLongitude] = west
        bBox[:eastLongitude] = east
        bBox[:southLatitude] = south
        bBox[:northLatitude] = north

        return bBox

    end