planning

node_modules/ol/src/proj/Units.js

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+/**
+ * @module ol/proj/Units
+ */
+
+/**
+ * Projection units: `'degrees'`, `'ft'`, `'m'`, `'pixels'`, `'tile-pixels'` or
+ * `'us-ft'`.
+ * @enum {string}
+ */
+const Units = {
+  /**
+   * Radians
+   * @api
+   */
+  RADIANS: 'radians',
+  /**
+   * Degrees
+   * @api
+   */
+  DEGREES: 'degrees',
+  /**
+   * Feet
+   * @api
+   */
+  FEET: 'ft',
+  /**
+   * Meters
+   * @api
+   */
+  METERS: 'm',
+  /**
+   * Pixels
+   * @api
+   */
+  PIXELS: 'pixels',
+  /**
+   * Tile Pixels
+   * @api
+   */
+  TILE_PIXELS: 'tile-pixels',
+  /**
+   * US Feet
+   * @api
+   */
+  USFEET: 'us-ft',
+};
+
+/**
+ * See http://duff.ess.washington.edu/data/raster/drg/docs/geotiff.txt
+ * @type {Object<number, Units>}
+ */
+const unitByCode = {
+  '9001': Units.METERS,
+  '9002': Units.FEET,
+  '9003': Units.USFEET,
+  '9101': Units.RADIANS,
+  '9102': Units.DEGREES,
+};
+
+/**
+ * @param {number} code Unit code.
+ * @return {Units} Units.
+ */
+export function fromCode(code) {
+  return unitByCode[code];
+}
+
+/**
+ * Meters per unit lookup table.
+ * @const
+ * @type {Object<Units, number>}
+ * @api
+ */
+export const METERS_PER_UNIT = {};
+// use the radius of the Normal sphere
+METERS_PER_UNIT[Units.RADIANS] = 6370997 / (2 * Math.PI);
+METERS_PER_UNIT[Units.DEGREES] = (2 * Math.PI * 6370997) / 360;
+METERS_PER_UNIT[Units.FEET] = 0.3048;
+METERS_PER_UNIT[Units.METERS] = 1;
+METERS_PER_UNIT[Units.USFEET] = 1200 / 3937;
+
+export default Units;