leaflet-canvaslayer-field/spec/FieldSpec.js

A set of layers using canvas to draw ASCIIGrid or GeoTIFF files. This includes a basic raster layer (*ScalaField*) and an animated layer for vector fields, such as wind or currents (*VectorFieldAnim*)

describe('Field', function() {
    let Field = L.Field;
    let ScalarField = L.ScalarField;

    let dataFolder = 'base/docs/data';
    let f;

    beforeEach(function(fileLoaded) {
        d3.text(`${dataFolder}/U.asc`, function(asc) {
            f = ScalarField.fromASCIIGrid(asc);
            fileLoaded();
        });
    });

    it('gives general info about its cells and extent', function() {
        expect(f.nCols).toEqual(10);
        expect(f.nRows).toEqual(10);

        let xmin = -3.769470033164;
        let ymin = 43.460341898838;
        let xmax = -3.764419377714;
        let ymax = 43.465392554288;

        expect(f.xllCorner).toEqual(xmin);
        expect(f.yllCorner).toEqual(ymin);
        expect(f.xurCorner).toBeCloseTo(xmax, 8);
        expect(f.yurCorner).toBeCloseTo(ymax, 8);

        const size = 0.000505065545;
        expect(f.cellXSize).toEqual(size);
        expect(f.cellYSize).toEqual(size);

        expect(f.numCells()).toEqual(100);
    });

    it('is a regular grid with nCols & nRows', function() {
        expect(f.grid).not.toBe(null);

        let i = f.grid.length;
        let j = f.grid[0].length;
        expect(i).toBe(f.nRows);
        expect(j).toBe(f.nCols);
    });

    it('can generate a random position inside', function() {
        let pos = f.randomPosition();
        expect(pos).not.toBe(null);
        expect(f.contains(pos.x, pos.y)).toBe(true);

        let pos2 = f.randomPosition();
        expect(pos2).not.toBe(pos);
    });

    it('knows the longitude & latitude for each cell', function() {
        // longitudes
        let xminCenter = f._longitudeAtX(0);
        expect(xminCenter).toBeCloseTo(-3.7692175003915001, 6);

        let xmaxCenter = f._longitudeAtX(9);
        expect(xmaxCenter).toBeCloseTo(-3.7646719104865003, 6);

        // latitudes
        let ymaxCenter = f._latitudeAtY(0);
        expect(ymaxCenter).toBeCloseTo(43.465140021515502, 6);

        let yminCenter = f._latitudeAtY(9);
        expect(yminCenter).toBeCloseTo(43.460594431610502, 6);

        //
        let first = f._lonLatAtIndexes(0, 0);
        expect(first[0]).toBeCloseTo(-3.7692175003915001, 7);
        expect(first[1]).toBeCloseTo(43.465140021515502, 7);

        let last = f._lonLatAtIndexes(9, 9);
        expect(last[0]).toBeCloseTo(-3.7646719104865003, 7);
        expect(last[1]).toBeCloseTo(43.460594431610502, 7);

        //
        let p = f._lonLatAtIndexes(0, 8);
        expect(p[0]).toBeCloseTo(-3.7692175001640003, 7);
        expect(p[1]).toBeCloseTo(43.461099497838006, 7);
    });

    it("doesn't return a value for a lon-lat outside of the grid ", function() {
        let lon = -3.710591474014617;
        let lat = 43.47082043045964;
        expect(f.hasValueAt(lon, lat)).toBe(false);
    });

    it('accepts a spatialMask', function() {
        let lon = (f.xllCorner + f.xurCorner) / 2.0;
        let lat = (f.yllCorner + f.yurCorner) / 2.0;
        expect(f.contains(lon, lat)).toBe(true);

        const aRectangle = {
            type: 'Feature',
            properties: { name: 'small south-east portion' },
            geometry: {
                type: 'Polygon',
                coordinates: [
                    [
                        [-3.76620135256, 43.462119341],
                        [-3.76413446895, 43.462119341],
                        [-3.76413446895, 43.4600412382],
                        [-3.76620135256, 43.4600412382],
                        [-3.76620135256, 43.462119341]
                    ]
                ]
            }
        };
        f.setSpatialMask(aRectangle);
        expect(f.contains(lon, lat)).toBe(false);
    });

    describe('Field [0-360º] (simple360.asc == 6 x 3 cells))', function() {
        let f360;

        beforeEach(function(fileLoaded2) {
            d3.text(`${dataFolder}/simple360.asc`, function(asc) {
                f360 = ScalarField.fromASCIIGrid(asc);
                fileLoaded2();
            });
        });

        it('supports 0-360 longitudes', function() {
            expect(f360.longitudeNeedsToBeWrapped).toBe(true);
        });

        it('returns wrapped extent', function() {
            // const original = [ -0.25, -90.25, 359.75, 90.25 ];  //wrapped, as in some NOAA products
            const expected = [-180, -90, 180, 90];
            expect(expected).toEqual(f360.extent());
        });

        it('contains points in [-180, 180] range', function() {
            expect(f360.contains(-180, 0)).toBe(true);
            expect(f360.contains(0, 0)).toBe(true);
            expect(f360.contains(180, 0)).toBe(true);
        });

        it('returns wrapped longitudes for cells', function() {
            // longitudes
            let xminCenter = f360._longitudeAtX(0);
            expect(xminCenter).toBe(0);

            let xmaxCenter = f360._longitudeAtX(5);
            expect(xmaxCenter).toBe(-60);

            // //
            let first = f360._lonLatAtIndexes(0, 0);
            expect(first[0]).toBe(0);
            expect(first[1]).toBe(60);

            let last = f360._lonLatAtIndexes(5, 2);
            expect(last[0]).toBe(-60);
            expect(last[1]).toBe(-60);
        });

        it('returns correct values', function() {
            // raster original values...
            //  corners...
            expect(f360.valueAt(-30, 90)).toBe(1); // upper-left
            expect(f360.valueAt(-30, -90)).toBe(13); // bottom-left
            expect(f360.valueAt(-30.1, 90)).toBe(6); // upper-right;
            expect(f360.valueAt(-30.1, -90)).toBe(18); // bottom-right

            expect(f360.valueAt(-30, 0)).toBe(7); // middle-left
            expect(f360.valueAt(-30.1, 0)).toBe(12); // middle-right

            //  around the 180º meridian...
            expect(f360.valueAt(179, 0)).toBe(10);
            expect(f360.valueAt(-179, 0)).toBe(10);
        });
    });
});