wv.proj.change.js

/*
 * NASA Worldview
 *
 * This code was originally developed at NASA/Goddard Space Flight Center for
 * the Earth Science Data and Information System (ESDIS) project.
 *
 * Copyright (C) 2013 - 2014 United States Government as represented by the
 * Administrator of the National Aeronautics and Space Administration.
 * All Rights Reserved.
 */

/**
 * @module wv.proj
 */
var wv = wv || {};
wv.proj = wv.proj || {};

/**
 * @class wv.proj.change
 */
wv.proj.change = wv.proj.change || function(models) {

    var PROJECTION_CHANGE_DATE = new Date(Date.UTC(2013, 5, 6));
    var EARLIEST_CHANGE_DATE = new Date(Date.UTC(2012, 11, 31));
    var DO_NOT_SHOW_AGAIN = "arcticProjectionChangeNotification";
    var notified = false;
    var polarVisited = 0;
    var self = {};

    self.events = wv.util.events();
    self.old = false;
    self.crs = null;
    self.epsg = null;

    var init = function() {
        models.proj.register("EPSG:3995",
            "+title=WGS 84 / Arctic Polar Stereographic +proj=stere " +
            "lat_0=90 +lat_ts=71 +lon_0=0 +k=1 +x_0=0 +y_0=0 " +
            "+datum=WGS84 +units=m +no_def");
        models.proj.events.on("select", onChange);
        models.date.events.on("select", onChange);
        update();
    };

    var update = function() {
        var proj = models.proj.selected;
        self.old = false;

        if ( proj.id === "arctic" || proj.id === "antarctic" ) {
            polarVisited = polarVisited + 1;
            var day = models.date.selected.getTime();
            var change = PROJECTION_CHANGE_DATE.getTime();
            var earliest = EARLIEST_CHANGE_DATE.getTime();
            self.old = day < change && day > earliest;
        }

        if ( proj.id === "arctic" && self.old ) {
            self.crs = "EPSG:3995";
            self.epsg = 3995;
        } else {
            self.crs = proj.crs;
            self.epsg = proj.epsg;
        }
    };

    var onChange = function() {
        var wasOld = self.old;
        update();
        self.events.trigger("select", self);
        if ( polarVisited > 1 && wasOld !== self.old ) {
            checkNotify();
        }
    };

    var checkNotify = function() {
        // If the flag cannot be stored in local storage, do not notify
        // the user which will constantly annoy them.
        if ( !wv.util.browser.localStorage ) {
            return;
        }
        if ( wv.util.localStorage(DO_NOT_SHOW_AGAIN) === "true" ) {
            return;
        }
        if ( notified ) {
            return;
        }
        notify();
    };

    var notify = function() {
        notified = true;
        var message = [
            "From 2013-01-01 to 2013-06-05, imagery in the polar projections",
            " are different than the other dates as follows:",
            "<br/><br/>",
            "The <b>Arctic projection</b> is in Arctic Polar ",
            "Stereographic (EPSG:3995, \"Greenwich down\") rather than NSIDC ",
            " Polar Stereographic North (EPSG:3413, \"Greenland down\"). ",
            "Coastlines and Graticule for this time range ",
            "can be found in the Add Layer tab by searching for ",
            " \"EPSG:3995\". Note that the image snapshot tool will not work ",
            "for Arctic imagery during this time range.",
            "<br/><br/>" +

            "The <b>Antarctic projection</b> is a sphere with radius of ",
            "6371007.181 meters during these dates rather than being ",
            "projected onto the WGS84 ",
            " ellipsoid. For all other dates, the projection is now the ",
            "correct Antarctic Polar Stereographic (EPSG:3031). This change ",
            "results in a shift of the imagery that ranges up to tens of ",
            "kilometers, depending on the location.",
            "<br/><br/>",

			"Imagery during this time range will be reprocessed during winter ",
            "2017-18 to be made consistent with all other imagery. In the ",
            "meantime, imagery will continue to be back-processed to the ",
            "start of the Terra and Aqua missions in 2000 and 2002, ",
            "respectively.",
            "<br/><br/>",

            "Thanks for your patience as we improve and expand our ",
            "imagery archive.",
            "<br/><br/>",

            "<input id='arcticChangeNoticeDontShowAgain' value='false' ",
                "type='checkbox'>Do not show again"
        ].join("");
        wv.ui.notify(message, "Notice", 400);
        var $check = $("#arcticChangeNoticeDontShowAgain");
        $check.on("click", function() {
            if ( $check.is(":checked") ) {
                wv.util.localStorage(DO_NOT_SHOW_AGAIN, "true");
            }
        });
    };


    init();
    return self;
};