Merge pull request #11719 from ahocevar/less-aggressie-3857-clamping

Clamp EPSG:3857 y to lowest/highest possible value instead of validity extent
This commit is contained in:
Andreas Hocevar
2020-11-19 13:51:47 +01:00
committed by GitHub
2 changed files with 20 additions and 10 deletions

View File

@@ -31,6 +31,13 @@ export const EXTENT = [-HALF_SIZE, -HALF_SIZE, HALF_SIZE, HALF_SIZE];
*/
export const WORLD_EXTENT = [-180, -85, 180, 85];
/**
* Maximum safe value in y direction
* @const
* @type {number}
*/
export const MAX_SAFE_Y = RADIUS * Math.log(Math.tan(Math.PI / 2));
/**
* @classdesc
* Projection object for web/spherical Mercator (EPSG:3857).
@@ -87,14 +94,13 @@ export function fromEPSG4326(input, opt_output, opt_dimension) {
output = new Array(length);
}
}
const halfSize = HALF_SIZE;
for (let i = 0; i < length; i += dimension) {
output[i] = (halfSize * input[i]) / 180;
output[i] = (HALF_SIZE * input[i]) / 180;
let y = RADIUS * Math.log(Math.tan((Math.PI * (+input[i + 1] + 90)) / 360));
if (y > halfSize) {
y = halfSize;
} else if (y < -halfSize) {
y = -halfSize;
if (y > MAX_SAFE_Y) {
y = MAX_SAFE_Y;
} else if (y < -MAX_SAFE_Y) {
y = -MAX_SAFE_Y;
}
output[i + 1] = y;
}