Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | 1x 2x 1x 1x 1x 1x 1x 1x | /** ****************************************************************************************************
* File: sizeOf.js
* Project: geohash
* @author Nick Soggin <iSkore@users.noreply.github.com> on 19-Feb-2019
*******************************************************************************************************/
'use strict';
const
{ PRECISION_AREA } = require( './variables' );
/**
* sizeOf
* Calculate the size of a given geohash
* | Precision | Width | Height |
* |:---------:|:-----------:|:-----------:|
* | 1 | `≤ 5,000km` | `× 5,000km` |
* | 2 | `≤ 1,250km` | `× 625km` |
* | 3 | `≤ 156km` | `× 156km` |
* | 4 | `≤ 39.1km` | `× 19.5km` |
* | 5 | `≤ 4.89km` | `× 4.89km` |
* | 6 | `≤ 1.22km` | `× 0.61km` |
* | 7 | `≤ 153m` | `× 153m` |
* | 8 | `≤ 38.2m` | `× 19.1m` |
* | 9 | `≤ 4.77m` | `× 4.77m` |
* | 10 | `≤ 1.19m` | `× 0.596m` |
* | 11 | `≤ 149mm` | `× 149mm` |
* | 12 | `≤ 37.2mm` | `× 18.6mm` |
*
* @param {string} geohash - Geohash to determine precision size
* @return {{geohash: string, area: number, precision, width, height}} - area, width, and high in meters
* @example
*
* sizeOf( 'dqcjpxetz' );
* // { geohash: 'dqcjpxetz', precision: 9, width: 4.77, height: 4.77, area: 22.7527 }
*/
function sizeOf( geohash ) {
if ( geohash.length === 0 ) {
throw new Error( 'Invalid geohash' );
}
const
precision = geohash.length,
{ width, height } = PRECISION_AREA[ precision ],
area = width * height;
return { geohash, precision, width, height, area };
}
module.exports = sizeOf;
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