@zwaarcontrast/ol-graticule-nei

Netherlands East Indies WWII grids for @zwaarcontrast/ol-graticule, both on Bessel 1841 / Batavia datum (EPSG:8452 shift to WGS84):

• NEI Southern Zone (NEI:SOUTHERN_ZONE): Java and the Lesser Sundas. Lambert Conformal Conic, one standard parallel, origin 8°S 110°E, k0 0.9997, false origin 550 000 m E / 400 000 m N. Not in EPSG.
• NEI Equatorial Zone (EPSG:3001, Batavia / NEIEZ): the rest of the archipelago. Mercator, lon_0 110°E, k0 0.997, false origin 3 900 000 m E / 900 000 m N.

Live demo: https://zwaarcontrast.nl/ol-graticule/ol-graticule-nei/

Zone parameters and limits: C. J. Mugnier, "Grids & Datums: Netherlands East Indies", citing US Army Map Service "Notes on East Indies Maps" (1945). The Southern Zone is checked against the Batavia Military Guide Map 1:20 000 (HIND/SEA/B/951, Dec 1945), whose 195 to 206 km E × 595 to 609 km N frame lands on Jakarta.

Each zone is clipped to Mugnier's limits. The source leaves the Equatorial Zone's western limit open, so it is closed at 94°E past Sumatra's coast; unlike EPSG:3001's area of use, the Equatorial Zone here excludes Java, which the Southern Zone covers.

The datum shift is EPSG:8452, "Batavia to WGS 84 (1)": three translations with 6 m accuracy, which EPSG defines only for Bali, Java and western Sumatra. Both zones apply it throughout; outside that area its accuracy is unknown.

Early 1942 British DSvy Java sheets print the Southern Zone grid with +3 000 000 m E and +1 000 000 m N; that variant is not registered.

Usage

import { UniversalGraticule } from '@zwaarcontrast/ol-graticule';
import { createNEISouthernZoneGridSystem } from '@zwaarcontrast/ol-graticule-nei';

map.addLayer(
  new UniversalGraticule({ gridSystem: createNEISouthernZoneGridSystem() }),
);

Both factories take the ProjectedGridSystem options except crs, proj4Def and extent, which the zone fixes. NEI_GRIDS holds every zone keyed by CRS (crs, name, proj4, validityWgs84, createGridSystem()). The CRS codes, proj4 strings and WGS84 validity rings are also exported ol-free from @zwaarcontrast/ol-graticule-nei/headless.