mirror of
https://github.com/apache/superset.git
synced 2024-09-19 12:09:42 -04:00
29 lines
1.0 KiB
JavaScript
29 lines
1.0 KiB
JavaScript
/* eslint global-require: 0 */
|
|
const d3 = window.d3 || require('d3');
|
|
|
|
export const EARTH_CIRCUMFERENCE_KM = 40075.16;
|
|
export const LUMINANCE_RED_WEIGHT = 0.2126;
|
|
export const LUMINANCE_GREEN_WEIGHT = 0.7152;
|
|
export const LUMINANCE_BLUE_WEIGHT = 0.0722;
|
|
export const MILES_PER_KM = 1.60934;
|
|
export const DEFAULT_LONGITUDE = -122.405293;
|
|
export const DEFAULT_LATITUDE = 37.772123;
|
|
export const DEFAULT_ZOOM = 11;
|
|
|
|
export function kmToPixels(kilometers, latitude, zoomLevel) {
|
|
// Algorithm from: http://wiki.openstreetmap.org/wiki/Zoom_levels
|
|
const latitudeRad = latitude * (Math.PI / 180);
|
|
// Seems like the zoomLevel is off by one
|
|
const kmPerPixel = EARTH_CIRCUMFERENCE_KM * Math.cos(latitudeRad) / Math.pow(2, zoomLevel + 9);
|
|
return d3.round(kilometers / kmPerPixel, 2);
|
|
}
|
|
|
|
export function isNumeric(num) {
|
|
return !isNaN(parseFloat(num)) && isFinite(num);
|
|
}
|
|
|
|
export function rgbLuminance(r, g, b) {
|
|
// Formula: https://en.wikipedia.org/wiki/Relative_luminance
|
|
return (LUMINANCE_RED_WEIGHT * r) + (LUMINANCE_GREEN_WEIGHT * g) + (LUMINANCE_BLUE_WEIGHT * b);
|
|
}
|