(window["webpackJsonp"] = window["webpackJsonp"] || []).push([[120],{

/***/ 349:
/***/ (function(module, __webpack_exports__, __webpack_require__) {

"use strict";
__webpack_require__.r(__webpack_exports__);
/* harmony import */ var _src_ol_Map_js__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(3);
/* harmony import */ var _src_ol_source_Raster_js__WEBPACK_IMPORTED_MODULE_1__ = __webpack_require__(162);
/* harmony import */ var _src_ol_View_js__WEBPACK_IMPORTED_MODULE_2__ = __webpack_require__(2);
/* harmony import */ var _src_ol_source_XYZ_js__WEBPACK_IMPORTED_MODULE_3__ = __webpack_require__(27);
/* harmony import */ var _src_ol_layer_js__WEBPACK_IMPORTED_MODULE_4__ = __webpack_require__(5);
/* harmony import */ var _src_ol_layer_js__WEBPACK_IMPORTED_MODULE_5__ = __webpack_require__(69);






var minVgi = 0;
var maxVgi = 0.25;
var bins = 10;

/**
 * Calculate the Vegetation Greenness Index (VGI) from an input pixel.  This
 * is a rough estimate assuming that pixel values correspond to reflectance.
 * @param {Array<number>} pixel An array of [R, G, B, A] values.
 * @return {number} The VGI value for the given pixel.
 */
function vgi(pixel) {
  var r = pixel[0] / 255;
  var g = pixel[1] / 255;
  var b = pixel[2] / 255;
  return (2 * g - r - b) / (2 * g + r + b);
}

/**
 * Summarize values for a histogram.
 * @param {numver} value A VGI value.
 * @param {Object} counts An object for keeping track of VGI counts.
 */
function summarize(value, counts) {
  var min = counts.min;
  var max = counts.max;
  var num = counts.values.length;
  if (value < min) {
    // do nothing
  } else if (value >= max) {
    counts.values[num - 1] += 1;
  } else {
    var index = Math.floor((value - min) / counts.delta);
    counts.values[index] += 1;
  }
}

/**
 * Use aerial imagery as the input data for the raster source.
 */

var key = 'get_your_own_D6rA4zTHduk6KOKTXzGB';
var attributions =
  '<a href="https://www.maptiler.com/copyright/" target="_blank">&copy; MapTiler</a> ' +
  '<a href="https://www.openstreetmap.org/copyright" target="_blank">&copy; OpenStreetMap contributors</a>';

var aerial = new _src_ol_source_XYZ_js__WEBPACK_IMPORTED_MODULE_3__[/* default */ "a"]({
  attributions: attributions,
  url: 'https://api.maptiler.com/tiles/satellite/{z}/{x}/{y}.jpg?key=' + key,
  maxZoom: 20,
  crossOrigin: '',
});

/**
 * Create a raster source where pixels with VGI values above a threshold will
 * be colored green.
 */
var raster = new _src_ol_source_Raster_js__WEBPACK_IMPORTED_MODULE_1__[/* default */ "a"]({
  sources: [aerial],
  /**
   * Run calculations on pixel data.
   * @param {Array} pixels List of pixels (one per source).
   * @param {Object} data User data object.
   * @return {Array} The output pixel.
   */
  operation: function (pixels, data) {
    var pixel = pixels[0];
    var value = vgi(pixel);
    summarize(value, data.counts);
    if (value >= data.threshold) {
      pixel[0] = 0;
      pixel[1] = 255;
      pixel[2] = 0;
      pixel[3] = 128;
    } else {
      pixel[3] = 0;
    }
    return pixel;
  },
  lib: {
    vgi: vgi,
    summarize: summarize,
  },
});
raster.set('threshold', 0.1);

function createCounts(min, max, num) {
  var values = new Array(num);
  for (var i = 0; i < num; ++i) {
    values[i] = 0;
  }
  return {
    min: min,
    max: max,
    values: values,
    delta: (max - min) / num,
  };
}

raster.on('beforeoperations', function (event) {
  event.data.counts = createCounts(minVgi, maxVgi, bins);
  event.data.threshold = raster.get('threshold');
});

raster.on('afteroperations', function (event) {
  schedulePlot(event.resolution, event.data.counts, event.data.threshold);
});

var map = new _src_ol_Map_js__WEBPACK_IMPORTED_MODULE_0__[/* default */ "a"]({
  layers: [
    new _src_ol_layer_js__WEBPACK_IMPORTED_MODULE_4__[/* default */ "a"]({
      source: aerial,
    }),
    new _src_ol_layer_js__WEBPACK_IMPORTED_MODULE_5__[/* default */ "a"]({
      source: raster,
    }) ],
  target: 'map',
  view: new _src_ol_View_js__WEBPACK_IMPORTED_MODULE_2__[/* default */ "a"]({
    center: [-9651695, 4937351],
    zoom: 13,
    minZoom: 12,
    maxZoom: 19,
  }),
});

var timer = null;
function schedulePlot(resolution, counts, threshold) {
  if (timer) {
    clearTimeout(timer);
    timer = null;
  }
  timer = setTimeout(plot.bind(null, resolution, counts, threshold), 1000 / 60);
}

var barWidth = 15;
var plotHeight = 150;
var chart = d3
  .select('#plot')
  .append('svg')
  .attr('width', barWidth * bins)
  .attr('height', plotHeight);

var chartRect = chart.node().getBoundingClientRect();

var tip = d3.select(document.body).append('div').attr('class', 'tip');

function plot(resolution, counts, threshold) {
  var yScale = d3
    .scaleLinear()
    .domain([0, d3.max(counts.values)])
    .range([0, plotHeight]);

  var bar = chart.selectAll('rect').data(counts.values);

  bar.enter().append('rect');

  bar
    .attr('class', function (count, index) {
      var value = counts.min + index * counts.delta;
      return 'bar' + (value >= threshold ? ' selected' : '');
    })
    .attr('width', barWidth - 2);

  bar
    .transition()
    .attr('transform', function (value, index) {
      return (
        'translate(' +
        index * barWidth +
        ', ' +
        (plotHeight - yScale(value)) +
        ')'
      );
    })
    .attr('height', yScale);

  bar.on('mousemove', function (count, index) {
    var threshold = counts.min + index * counts.delta;
    if (raster.get('threshold') !== threshold) {
      raster.set('threshold', threshold);
      raster.changed();
    }
  });

  bar.on('mouseover', function (count, index) {
    var area = 0;
    for (var i = counts.values.length - 1; i >= index; --i) {
      area += resolution * resolution * counts.values[i];
    }
    tip.html(message(counts.min + index * counts.delta, area));
    tip.style('display', 'block');
    tip.transition().style({
      left: chartRect.left + index * barWidth + barWidth / 2 + 'px',
      top: d3.event.y - 60 + 'px',
      opacity: 1,
    });
  });

  bar.on('mouseout', function () {
    tip
      .transition()
      .style('opacity', 0)
      .each('end', function () {
        tip.style('display', 'none');
      });
  });
}

function message(value, area) {
  var acres = (area / 4046.86)
    .toFixed(0)
    .replace(/\B(?=(\d{3})+(?!\d))/g, ',');
  return acres + ' acres at<br>' + value.toFixed(2) + ' VGI or above';
}


/***/ })

},[[349,0]]]);
//# sourceMappingURL=raster.js.map