src/layers/PolygonSeries.js
import L from 'leaflet'
import {indexOfNearest, minMaxOfRange, isDomain, fromDomain, ensureClockwisePolygon, getPointInPolygonsFn} from 'covutils'
import {enlargeExtentIfEqual} from './palettes.js'
import {CoverageMixin} from './CoverageMixin.js'
import {EventMixin} from '../util/EventMixin.js'
import {PaletteMixin} from './PaletteMixin.js'
import {DEFAULT_COLOR} from './Point.js'
// TODO nearly identical to VerticalProfile
/**
* Renderer for Coverages conforming to the CovJSON domain type `PolygonSeries`.
*
* @example
* var cov = ... // get Coverage data
* var layer = new C.PolygonSeries(cov, {
* parameter: 'salinity',
* time: new Date('2015-01-01T12:00:00Z'),
* defaultColor: 'black',
* palette: C.linearPalette(['#FFFFFF', '#000000'])
* })
*
* @see https://covjson.org/domain-types/#polygonseries
*
* @emits {DataLayer#afterAdd} Layer is initialized and was added to the map
* @emits {DataLayer#dataLoading} Data loading has started
* @emits {DataLayer#dataLoad} Data loading has finished (also in case of errors)
* @emits {DataLayer#error} Error when loading data
* @emits {DataLayer#axisChange} Axis coordinate has changed (e.axis === 'time')
* @emits {PaletteMixin#paletteChange} Palette has changed
* @emits {PaletteMixin#paletteExtentChange} Palette extent has changed
* @emits {Point#click} when the polygon was clicked
*
* @extends {L.Layer}
* @extends {CoverageMixin}
* @extends {PaletteMixin}
* @implements {DataLayer}
*/
export class PolygonSeries extends PaletteMixin(CoverageMixin(L.Layer)) {
/**
* An optional time axis target value can be defined with the 'time' property.
* The closest values on the time axis is chosen.
*
* @param {Coverage|Domain} cov The coverage or domain object to visualize.
* @param {Object} [options] The options object.
* @param {string} [options.parameter] The key of the parameter to display, not needed for domain objects.
* @param {Date} [options.time] The initial time step to display.
* @param {Palette} [options.palette] The initial color palette to use, the default depends on the parameter type.
* @param {string} [options.paletteExtent='full'] The initial palette extent, either 'full' or specific: [-10,10].
* @param {string} [options.defaultColor='black'] The color to use for missing data or if no parameter is set.
*/
constructor (cov, options) {
super()
if (isDomain(cov)) {
cov = fromDomain(cov)
delete options.keys
options.parameter = cov.parameters.keys().next().value
}
if (!options.paletteExtent) {
options.paletteExtent = 'full'
}
L.Util.setOptions(this, options)
this._cov = cov
let paramKey = options.keys ? options.keys[0] : options.parameter
this._param = paramKey ? cov.parameters.get(paramKey) : null
this._axesSubset = {
t: {coordPref: options.time}
}
this._defaultColor = options.defaultColor || DEFAULT_COLOR
}
/**
* @ignore
* @override
*/
onAdd (map) {
this._map = map
this.load()
.then(() => this.initializePalette())
.then(() => {
this._unproject()
this._addPolygon()
this._pointInPolygonPreprocess()
this.fire('afterAdd')
})
}
_unproject () {
let unproject = this.projection.unproject
let axis = this.domain.axes.get('composite')
let ix = axis.coordinates.indexOf(this._projX)
let iy = axis.coordinates.indexOf(this._projY)
this._polygonLonLat = axis.values[0].map(ring => ring.map(coords => {
let {lat,lon} = unproject({x: coords[ix], y: coords[iy]})
return [lon,lat]
}))
}
_loadCoverageSubset () {
// adapted from Grid.js
let t = this._axesSubset.t
if (t.coordPref == undefined) {
t.idx = t.coord = undefined
} else {
let vals = this.domain.axes.get('t').values.map(v => v.getTime())
t.idx = indexOfNearest(vals, t.coordPref.getTime())
t.coord = vals[t.idx]
}
// Note that we don't subset the coverage currently, since there is no real need for it
}
/**
* @ignore
* @override
*/
onRemove () {
this._removePolygon()
}
/**
* Returns the geographic bounds of the coverage.
*
* @return {L.LatLngBounds}
*/
getBounds () {
return this._geojson.getBounds()
}
/**
* Returns the geographical center position of the coverage based on its bounding box.
*
* @return {L.LatLng}
*/
getLatLng () {
return this.getBounds().getCenter()
}
/**
* @ignore
* @override
*/
bindPopup (...args) {
this._popup = args
if (this._geojson) {
this._geojson.bindPopup(...args)
}
return this
}
/**
* @ignore
* @override
*/
openPopup () {
this._geojson.openPopup()
return this
}
/**
* @ignore
* @override
*/
closePopup () {
this._geojson.closePopup()
return this
}
/**
* The coverage object associated to this layer.
*
* @type {Coverage}
*/
get coverage () {
return this._cov
}
/**
* The parameter that is visualized.
*
* @type {Parameter}
*/
get parameter () {
return this._param
}
/**
* Sets the currently active time to the one closest to the given Date object.
*
* @type {Date|undefined}
*/
set time (val) {
let old = this.time
this._axesSubset.t.coordPref = val ? val.toISOString() : undefined
this._loadCoverageSubset()
if (old === this.time) return
this.redraw()
this.fire('axisChange', {axis: 'time'})
}
/**
* The currently active time on the temporal axis as Date object,
* or undefined if no time is set.
*
* @type {Date|undefined}
*/
get time () {
if (!this._axesSubset.t.coord) {
return
}
let time = this.domain.axes.get('t').values[this._axesSubset.t.idx]
return new Date(time)
}
/**
* The time slices that make up the coverage.
*
* @type {Array<Date>}
*/
get timeSlices () {
return this.domain.axes.get('t').values.map(t => new Date(t))
}
/**
* See {@link PaletteMixin}.
*
* @ignore
*/
canUsePalette () {
return this.time !== undefined
}
/**
* See {@link PaletteMixin}.
*
* @ignore
*/
computePaletteExtent (extent) {
if (extent === 'full') {
if (!this.parameter) {
throw new Error('palette extent cannot be computed when no parameter has been chosen')
}
extent = minMaxOfRange(this.range)
extent = enlargeExtentIfEqual(extent)
return Promise.resolve(extent)
} else {
throw new Error('Unknown extent specification: ' + extent)
}
}
_pointInPolygonPreprocess () {
let polygon = this._polygonLonLat
// TODO we assume spherical coordinates for now
let isCartesian = false
// A bit evil since this modifies in-place, but nothing bad should happen.
ensureClockwisePolygon(polygon, isCartesian)
let pointInPolygons = getPointInPolygonsFn([polygon])
this._pointInPolygon = point => pointInPolygons(point) !== -1
}
_addPolygon () {
let polygon = this._polygonLonLat
let geojson = {
"type": "Feature",
"properties": {
"color": this._getColor(this.getValue())
},
"geometry": {
"type": "Polygon",
"coordinates": polygon
}
}
this._geojson = L.geoJson(geojson, {
style: feature => ({
color: feature.properties.color,
fillOpacity: 1,
stroke: false
}),
onEachFeature: (feature, layer) => {
layer.on('click', e => this.fire('click', e))
}
})
if (this._popup) {
this._geojson.bindPopup(...this._popup)
}
this._geojson.addTo(this._map)
}
_removePolygon () {
this._map.removeLayer(this._geojson)
delete this._geojson
}
/**
* Return the displayed value (number, or null for no-data),
* or undefined if not fixed to a t-coordinate or parameter.
*
* @returns {number|null|undefined}
*/
getValue () {
if (this._param && this._axesSubset.t.coord !== undefined) {
let val = this.range.get({t: this._axesSubset.t.idx})
return val
}
}
/**
* Return the displayed value at a given geographic position.
* If out of bounds, then undefined is returned, otherwise a number or null (for no data).
*
* @param {L.LatLng} latlng
* @returns {number|null|undefined}
*/
getValueAt (latlng) {
if (!latlng) throw new Error('latlng parameter missing')
// TODO longitude wrapping
if (this._pointInPolygon([latlng.lng, latlng.lat])) {
return this.getValue()
}
}
// NOTE: this returns a string, not an {r,g,b} object as in other classes!
_getColor (val) {
if (val === null) {
// no-data
return this._defaultColor
} else if (val === undefined) {
// not fixed to a param or z-coordinate
return this._defaultColor
} else {
// use a palette
let idx = this.getPaletteIndex(val)
let {red, green, blue} = this.palette
return `rgb(${red[idx]}, ${green[idx]}, ${blue[idx]})`
}
}
_updatePolygon () {
this._removePolygon()
this._addPolygon()
}
/**
* Redraw the layer.
*/
redraw () {
this._updatePolygon()
this._geojson.redraw()
}
}
