itowns
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A JS/WebGL framework for 3D geospatial data visualization
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TypeScript
export default GeoidGrid;
/**
* An instance of `GeoidGrid` allows accessing some geoid height grid data from geographic instances (like some
* {@link Coordinates}). The geoid height grid data must contain geoid height values for a set of geographic points
* regularly dispatched on a planar surface.
*
* @property {Extent} extent The geographic extent of the geoid height grid data.
* @property {THREE.Vector2} step The distance between two consecutive points of the geoid height grid. The
* `x` value stands for the distance along the West-East direction, and the
* `y` value stands for the distance along the South-North direction.
* @property {THREE.Vector2} dimensions The planar dimensions of the geoid height grid data extent.
* @property {THREE.Vector2} dataSize The number of values in the gridded data along the West-East direction (`x`
* axis) and the South-North direction (`y` axis).
*
* @example
* // Create a set of gridded data.
* const data = [
* [1, 2, 3],
* [2, 3, 4],
* [3, 4, 5],
* ];
* // This set of data presents the following spatial distribution of geoid heights values :
* //
* // Latitudes ^
* // |
* // 41.0 | 3 4 5
* // 40.5 | 2 3 4
* // 40.0 | 1 2 3
* // |------------->
* // 1 2 3 Longitudes
*
* // Create a GeoidGrid allowing to access the gridded data.
* const geoidGrid = new GeoidGrid(
* new Extent('EPSG:4326', 1, 3, 40, 41),
* new THREE.Vector2(1, 0.5),
* (verticalIndex, horizontalIndex) => data[verticalIndex][horizontalIndex],
* );
*
* // Access a value of geoid height at some geographic coordinates.
* // The value is interpolated from the gridded data.
* const value = geoidGrid.getHeightAtCoordinates(
* new Coordinates('EPSG:4326', 1.5, 40.25)
* );
* // This should return 2.0, which is the result from the bi-linear
* // interpolation at the center of the `[[1, 2], [2, 3]]` subsection
* // of the grid data.
*/
declare class GeoidGrid {
/**
* @param {Extent} extent The geographic extent of the geoid height grid data.
* @param {THREE.Vector2} step The distance between two consecutive points of the geoid height grid. The
* `x` value stands for the distance along the West-East direction, and the
* `y` value stands for the distance along the South-North direction.
* @param {function} getData A method that allows reading a value in the geoid height grid from its
* vertical and horizontal indexes. The lower an index, the lower the
* coordinate on the corresponding axis - 0 being the index of the minimal
* coordinate of the gridded data on a given axis. In other words :
* - `getData(0, 0)` must return the geoid height value at the SOUTH-WEST
* corner of your data extent.
* - `getData(0, j)` must return a geoid height on the southern limit of your
* data extent.
* - `getData(i, 0)` must return a geoid height on the western limit of your
* data extent.
* - if your gridded data has dimensions (rowNumber, colNumber),
* `getData(rowNumber - 1, colNumber - 1)` must return the geoid height at
* the NORTH-EAST corner of your data extent.
*/
constructor(extent: Extent, step: THREE.Vector2, getData: Function);
extent: Extent;
step: THREE.Vector2;
dimensions: any;
dataSize: THREE.Vector2;
getData: Function;
/**
* Get the value of the geoid height at given geographic {@link Coordinates}. The geoid height value is
* bi-linearly interpolated from the gridded data accessed by the `GeoidGrid` instance.
*
* @param {Coordinates} coordinates Geographic coordinates to get the geoid height value at.
*
* @returns {number} The geoid height value at the given {@link Coordinates}, bi-interpolated from the gridded
* data accessed by the `GeoidGrid` instance.
*/
getHeightAtCoordinates(coordinates: Coordinates): number;
}
import * as THREE from 'three';
import { Coordinates } from '@itowns/geographic';