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refacto: migrate Crs to typescript
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@Desplandis
Desplandis committed Oct 11, 2024
1 parent cfb9d0f commit b6e923f
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Showing 2 changed files with 58 additions and 53 deletions.
103 changes: 50 additions & 53 deletions src/Core/Geographic/Crs.js → src/Core/Geographic/Crs.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,50 +2,55 @@ import proj4 from 'proj4';

proj4.defs('EPSG:4978', '+proj=geocent +datum=WGS84 +units=m +no_defs');

function isString(s) {
/**
* A projection as a CRS identifier string.
*/
export type ProjectionLike = string;

function isString(s: unknown): s is string {
return typeof s === 'string' || s instanceof String;
}

function mustBeString(crs) {
function mustBeString(crs: string) {
if (!isString(crs)) {
throw new Error(`Crs parameter value must be a string: '${crs}'`);
}
}

function isTms(crs) {
function isTms(crs: string) {
return isString(crs) && crs.startsWith('TMS');
}

function isEpsg(crs) {
function isEpsg(crs: string) {
return isString(crs) && crs.startsWith('EPSG');
}

function formatToTms(crs) {
function formatToTms(crs: string) {
mustBeString(crs);
return isTms(crs) ? crs : `TMS:${crs.match(/\d+/)[0]}`;
return isTms(crs) ? crs : `TMS:${crs.match(/\d+/)?.[0]}`;
}

function formatToEPSG(crs) {
function formatToEPSG(crs: string) {
mustBeString(crs);
return isEpsg(crs) ? crs : `EPSG:${crs.match(/\d+/)[0]}`;
return isEpsg(crs) ? crs : `EPSG:${crs.match(/\d+/)?.[0]}`;
}

const UNIT = {
DEGREE: 1,
METER: 2,
};
} as const;

function is4326(crs) {
function is4326(crs: ProjectionLike) {
return crs === 'EPSG:4326';
}

function isGeocentric(crs) {
function isGeocentric(crs: ProjectionLike) {
mustBeString(crs);
const projection = proj4.defs(crs);
return !projection ? false : projection.projName == 'geocent';
}

function _unitFromProj4Unit(projunit) {
function _unitFromProj4Unit(projunit: string) {
if (projunit === 'degrees') {
return UNIT.DEGREE;
} else if (projunit === 'm') {
Expand All @@ -55,22 +60,22 @@ function _unitFromProj4Unit(projunit) {
}
}

function toUnit(crs) {
function toUnit(crs: ProjectionLike) {
mustBeString(crs);
switch (crs) {
case 'EPSG:4326' : return UNIT.DEGREE;
case 'EPSG:4978' : return UNIT.METER;
default: {
const p = proj4.defs(formatToEPSG(crs));
if (!p) {
if (!p?.units) {
return undefined;
}
return _unitFromProj4Unit(p.units);
}
}
}

function toUnitWithError(crs) {
function toUnitWithError(crs: ProjectionLike) {
mustBeString(crs);
const u = toUnit(crs);
if (u === undefined) {
Expand All @@ -80,100 +85,92 @@ function toUnitWithError(crs) {
}

/**
* This module provides basic methods to manipulate a CRS (as a string).
*
* @module CRS
* This module provides basic methods to manipulate a CRS.
*/
export default {
/**
* Units that can be used for a CRS.
*
* @enum {number}
*/
UNIT,

/**
* Assert that the CRS is valid one.
* Assert that the CRS is a valid one.
*
* @param {string} crs - The CRS to validate.
* @param crs - The CRS to validate.
*
* @throws {Error} if the CRS is not valid.
* @throws {@link Error} if the CRS is not valid.
*/
isValid(crs) {
isValid(crs: ProjectionLike) {
toUnitWithError(crs);
},

/**
* Assert that the CRS is geographic.
*
* @param {string} crs - The CRS to validate.
* @return {boolean}
* @throws {Error} if the CRS is not valid.
* @param crs - The CRS to validate.
* @throws {@link Error} if the CRS is not valid.
*/
isGeographic(crs) {
isGeographic(crs: ProjectionLike) {
return (toUnitWithError(crs) == UNIT.DEGREE);
},

/**
* Assert that the CRS is using metric units.
*
* @param {string} crs - The CRS to validate.
* @return {boolean}
* @throws {Error} if the CRS is not valid.
* @param crs - The CRS to validate.
* @throws {@link Error} if the CRS is not valid.
*/
isMetricUnit(crs) {
isMetricUnit(crs: ProjectionLike) {
return (toUnit(crs) == UNIT.METER);
},

/**
* Get the unit to use with the CRS.
*
* @param {string} crs - The CRS to get the unit from.
* @return {number} Either `UNIT.METER`, `UNIT.DEGREE` or `undefined`.
* @param crs - The CRS to get the unit from.
* @returns Either `UNIT.METER`, `UNIT.DEGREE` or `undefined`.
*/
toUnit,

/**
* Is the CRS EPSG:4326 ?
* Is the CRS EPSG:4326?
*
* @param {string} crs - The CRS to test.
* @return {boolean}
* @param crs - The CRS to test.
*/
is4326,
/**
* Is the CRS geocentric ?
* Is the CRS geocentric?
* if crs isn't defined the method returns false.
*
* @param {string} crs - The CRS to test.
* @return {boolean}
* @param crs - The CRS to test.
*/
isGeocentric,

/**
* Give a reasonnable epsilon to use with this CRS.
*
* @param {string} crs - The CRS to use.
* @return {number} 0.01 if the CRS is EPSG:4326, 0.001 otherwise.
* @param crs - The CRS to use.
* @returns 0.01 if the CRS is EPSG:4326, 0.001 otherwise.
*/
reasonnableEpsilon(crs) {
reasonnableEpsilon(crs: ProjectionLike) {
if (is4326(crs)) {
return 0.01;
} else {
return 0.001;
}
},
/**
* format crs to European Petroleum Survey Group notation : EPSG:XXXX.
* Format crs to European Petroleum Survey Group notation: EPSG:XXXX.
*
* @param {string} crs The crs to format
* @return {string} formated crs
* @param crs - The crs to format
* @returns formated crs
*/
formatToEPSG,
/**
* format crs to tile matrix set notation : TMS:XXXX.
* Format crs to tile matrix set notation: TMS:XXXX.
*
* @param {string} crs The crs to format
* @return {string} formated crs
* @param crs - The crs to format
* @returns formated crs
*/
formatToTms,
isTms,
Expand All @@ -183,9 +180,9 @@ export default {
/**
* Define a proj4 projection as a string and reference.
*
* @param {string} code code is the projection's SRS code (only used internally by the Proj4js library)
* @param {string} proj4def is the Proj4 definition string for the projection to use
* @return {undefined}
* @param code - projection's SRS code (only used internally by the Proj4js
* library)
* @param proj4def - Proj4 definition string for the projection to use
*/
defs: (code, proj4def) => proj4.defs(code, proj4def),
defs: (code: string, proj4def: string) => proj4.defs(code, proj4def),
};
8 changes: 8 additions & 0 deletions test/unit/crs.js
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Original file line number Diff line number Diff line change
Expand Up @@ -34,13 +34,21 @@ describe('CRS assertions', function () {
assert.strictEqual(CRS.toUnit('EPSG:7133'), CRS.UNIT.DEGREE);
assert.strictEqual(CRS.toUnit('EPSG:4978'), CRS.UNIT.METER);
assert.strictEqual(CRS.toUnit('EPSG:3857'), CRS.UNIT.METER);
assert.strictEqual(CRS.toUnit('EPSG:INVALID'), undefined);
});

it('should check if the CRS is EPSG:4326', function () {
assert.ok(CRS.is4326('EPSG:4326'));
assert.ok(!CRS.is4326('EPSG:3857'));
});

it('should assert that the CRS is geocentric', function () {
assert.ok(!CRS.isGeocentric('EPSG:4326'));
assert.ok(!CRS.isGeocentric('EPSG:7133'));
assert.ok(CRS.isGeocentric('EPSG:4978'));
assert.ok(!CRS.isGeocentric('EPSG:3857'));
});

it('should return a reasonnable epsilon', function () {
assert.strictEqual(CRS.reasonnableEpsilon('EPSG:4326'), 0.01);
assert.strictEqual(CRS.reasonnableEpsilon('EPSG:3857'), 0.001);
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