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Support for Graticule Drawing for Grid Projections Other than EPSG4326 #15077

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Support for Graticule Drawing for Grid Projections Other than EPSG4326 #15077

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28 changes: 22 additions & 6 deletions src/ol/geom/flat/geodesic.js
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Expand Up @@ -142,10 +142,18 @@ export function greatCircleArc(
* @param {number} lat2 Latitude 2.
* @param {import("../../proj/Projection.js").default} projection Projection.
* @param {number} squaredTolerance Squared tolerance.
* @param {import("../../proj/Projection.js").default|undefined} sourceProjection Source projection.
* @return {Array<number>} Flat coordinates.
*/
export function meridian(lon, lat1, lat2, projection, squaredTolerance) {
const epsg4326Projection = getProjection('EPSG:4326');
export function meridian(
lon,
lat1,
lat2,
projection,
squaredTolerance,
sourceProjection
) {
sourceProjection = sourceProjection || getProjection('EPSG:4326');
return line(
/**
* @param {number} frac Fraction.
Expand All @@ -154,7 +162,7 @@ export function meridian(lon, lat1, lat2, projection, squaredTolerance) {
function (frac) {
return [lon, lat1 + (lat2 - lat1) * frac];
},
getTransform(epsg4326Projection, projection),
getTransform(sourceProjection, projection),
squaredTolerance
);
}
Expand All @@ -166,10 +174,18 @@ export function meridian(lon, lat1, lat2, projection, squaredTolerance) {
* @param {number} lon2 Longitude 2.
* @param {import("../../proj/Projection.js").default} projection Projection.
* @param {number} squaredTolerance Squared tolerance.
* @param {import("../../proj/Projection.js").default|undefined} sourceProjection Source projection.
* @return {Array<number>} Flat coordinates.
*/
export function parallel(lat, lon1, lon2, projection, squaredTolerance) {
const epsg4326Projection = getProjection('EPSG:4326');
export function parallel(
lat,
lon1,
lon2,
projection,
squaredTolerance,
sourceProjection
) {
sourceProjection = sourceProjection || getProjection('EPSG:4326');
return line(
/**
* @param {number} frac Fraction.
Expand All @@ -178,7 +194,7 @@ export function parallel(lat, lon1, lon2, projection, squaredTolerance) {
function (frac) {
return [lon1 + (lon2 - lon1) * frac, lat];
},
getTransform(epsg4326Projection, projection),
getTransform(sourceProjection, projection),
squaredTolerance
);
}
40 changes: 28 additions & 12 deletions src/ol/layer/Graticule.js
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Expand Up @@ -169,6 +169,7 @@ const INTERVALS = [
* [30, 10]
* ```
* @property {boolean} [wrapX=true] Whether to repeat the graticule horizontally.
* @property {import("../proj/Projection.js").default|string|undefined} [gridProjection] The Projection used to draw the graticule lines.
* @property {Object<string, *>} [properties] Arbitrary observable properties. Can be accessed with `#get()` and `#set()`.
*/

Expand Down Expand Up @@ -208,13 +209,25 @@ class Graticule extends VectorLayer {
delete baseOptions.lonLabelStyle;
delete baseOptions.latLabelStyle;
delete baseOptions.intervals;
delete baseOptions.gridProjection;
super(baseOptions);

/**
* @type {import("../proj/Projection.js").default}
*/
this.projection_ = null;

/**
* @type {import("../proj/Projection.js").default}
* @private
*/
this.gridProjection_ =
options.gridProjection === undefined
? getProjection('EPSG:4326')
: typeof options.gridProjection === 'string'
? getProjection(options.gridProjection)
: options.gridProjection;

/**
* @type {number}
* @private
Expand Down Expand Up @@ -1017,9 +1030,13 @@ class Graticule extends VectorLayer {
/** @type {Array<number>} **/
const p2 = [];
for (let i = 0, ii = this.intervals_.length; i < ii; ++i) {
const delta = clamp(this.intervals_[i] / 2, 0, 90);
const delta = clamp(this.intervals_[i] / 2, 0, this.maxLat_);
// Don't attempt to transform latitudes beyond the poles!
const clampedLat = clamp(centerLat, -90 + delta, 90 - delta);
const clampedLat = clamp(
centerLat,
this.minLat_ + delta,
this.maxLat_ - delta
);
p1[0] = centerLon - delta;
p1[1] = clampedLat - delta;
p2[0] = centerLon + delta;
Expand Down Expand Up @@ -1050,7 +1067,8 @@ class Graticule extends VectorLayer {
minLat,
maxLat,
this.projection_,
squaredTolerance
squaredTolerance,
this.gridProjection_
);
let lineString = this.meridians_[index];
if (!lineString) {
Expand Down Expand Up @@ -1120,7 +1138,8 @@ class Graticule extends VectorLayer {
minLon,
maxLon,
this.projection_,
squaredTolerance
squaredTolerance,
this.gridProjection_
);
let lineString = this.parallels_[index];
if (!lineString) {
Expand Down Expand Up @@ -1179,9 +1198,7 @@ class Graticule extends VectorLayer {
* @private
*/
updateProjectionInfo_(projection) {
const epsg4326Projection = getProjection('EPSG:4326');

const worldExtent = projection.getWorldExtent();
const worldExtent = this.gridProjection_.getExtent();

this.maxLat_ = worldExtent[3];
this.maxLon_ = worldExtent[2];
Expand All @@ -1191,7 +1208,7 @@ class Graticule extends VectorLayer {
// If the world extent crosses the dateline define a custom transform to
// return longitudes which wrap the dateline

const toLonLatTransform = getTransform(projection, epsg4326Projection);
const toLonLatTransform = getTransform(projection, this.gridProjection_);
if (this.minLon_ < this.maxLon_) {
this.toLonLatTransform_ = toLonLatTransform;
} else {
Expand All @@ -1216,7 +1233,7 @@ class Graticule extends VectorLayer {
// Transform the extent to get the limits of the view projection extent
// which should be available to the graticule

this.fromLonLatTransform_ = getTransform(epsg4326Projection, projection);
this.fromLonLatTransform_ = getTransform(this.gridProjection_, projection);
const worldExtentP = applyTransform(
[this.minLon_, this.minLat_, this.maxLon_, this.maxLat_],
this.fromLonLatTransform_,
Expand All @@ -1241,9 +1258,8 @@ class Graticule extends VectorLayer {
// Some projections may have a void area at the poles
// so replace any NaN latitudes with the min or max value closest to a pole

this.projectionCenterLonLat_ = this.toLonLatTransform_(
getCenter(projection.getExtent())
);
this.projectionCenterLonLat_ = getCenter(this.gridProjection_.getExtent());

if (isNaN(this.projectionCenterLonLat_[1])) {
this.projectionCenterLonLat_[1] =
Math.abs(this.maxLat_) >= Math.abs(this.minLat_)
Expand Down