io / proto-projection

Mirror page of Geo / Projection under the io sub-tree.

Exported symbols

export function sanitizeProjString(s: string): string;

export interface PointXY {
  x: number;
  y: number;
  z?: number;
}

export interface Projection {
  readonly projString: string;
  toLonLat(p: PointXY): PointXY;
  fromLonLat(p: PointXY): PointXY;
}

export function makeProjection(projString: string): Projection;

export function utmProjString(zone: number, hemisphere?: 'N' | 'S'): string;
export function utmZoneFromLon(lonDeg: number): number;

export const UTM_PRESETS: {
  readonly sunnyvale: string;
  readonly beijing: string;
  readonly shanghai: string;
  readonly shenzhen: string;
};

Source: src/io/proto/projection.ts:1-81.

Behaviour

• sanitizeProjString strips Apollo-style +lat_0={...} template braces.
• makeProjection builds a bidirectional proj4 pipeline between the PROJ string and WGS84.
• toLonLat / fromLonLat preserve z absence to keep round-trips byte-equal.
• utmProjString throws for zones outside [1, 60].
• utmZoneFromLon applies the 6°-per-zone rule.
• UTM_PRESETS exposes the four common Apollo deployment regions. apolloIOBridge.FALLBACK_PROJ = UTM_PRESETS.beijing.

Consumers

Consumer	Usage
src/io/proto/adapter.ts	makeProjection + transformPointsInMessage
src/io/apolloIOBridge.ts	UTM_PRESETS.beijing as fallback
src/store/projDialogStore.ts	populates the projection-picker UI presets

Notes

• No instance caching here — proj4 caches pipelines internally per (source, target) PROJ pair, so re-calling makeProjection with the same string is cheap.
• proj4 throws on malformed input; the bridge surfaces this as IMPORT/EXPORT ERROR.

See also

• Geo / Projection — top-level mirror.
• io/proto-adapter — primary consumer.

Contributors

kent

Changelog

Last edited 4 minutes ago

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8d55547-test(e2e): run the full playwright suite