Help Add the Option for 'ol/layer/Graticule' to Specify the Projection to Draw

Is your feature request related to a problem? Please describe. I want to draw TWD67 (the graticule for Taiwan), except for the hard-coded EPSG:4326.

Describe the solution you’d like So it would help If there is a option, like ‘projection’ for Graticule Class.

PoC After studying Graticule class, I found it is not hard to parametrize the ‘draw projection’. I did write a PoC (the whole code is copied from v6.2.1., except for those marked “@@” ) and works well. To be short:

1. parameterize for ‘draw projection’:
   • This requires to alter not only ol/layer/Graticule, but also ol/geom/flat/geodesic (for meridian and parallel functions)
2. require the ‘projection’ option as a Projection and not a ProjectionLike
   • Because my poc need getExtent() of ‘draw projeciton’ to set the limits (i.g., min/max lat/lon), and the information is not provided when registering proj4. If the option is ProjectinLike, ensure that itsextent property is defined (see below https://github.com/openlayers/openlayers/issues/10913#issuecomment-612595474)

Demo web (Please zoom out to level 5~6 to see this is a “local” graticule)

Request I’m new to OL. For code coherence, It would better If any contributor can help review and code the idea.

Many thanks.

[dayanuyim]

Thanks! These are what I am looking for!

[mike-000]

If you set up a projection using the constructor you must add it before it can be looked by code using getProjection (but getProjection takes projectionLike so you can pass the projection without having to add it)

const TWD67 = new Projection({
  code: 'EPSG:3828',
  extent: [ 145616.57, 2419514.81, 356704.34, 2803869.61 ],
  worldExtent: [119.99, 21.87, 122.06, 25.34 ],
  units: 'm',
});
addProjection(TWD67);

Alternatively you could simply look up the projection already defined by registering proj4 and set an extent

const TWD67 = getProjection('EPSG:3828');
TWD67.setExtent([ 145616.57, 2419514.81, 356704.34, 2803869.61 ]);
TWD67.setWorldExtent([119.99, 21.87, 122.06, 25.34 ]);