Documentation for mapping caves

[antevens]

I've been trying to add underground layers and have them rendered but despite my best efforts I'm unable to get underground layers to render.

I'm propably missing something basic but so far it's eluded me.
My current config includes the following sections and I've cleared all tiles and the mapserver.sqlite DB on multiple occations.

Any thoughts on why nothing would be rendereed?

"layers": [
	{
		"id": 0,
		"name": "Ground",
		"from": -1,
		"to": 10
	},
	{
		"id": 1,
		"name": "Sky",
		"from": 11,
		"to": 24
	},
	{
		"id": 2,
		"name": "BaseCave",
		"from": -2400,
		"to": -2300
	},
	{
		"id": 3,
		"name": "Caves",
		"from": -2335,
		"to": -2350
	}
],

[BuckarooBanzay]

Yeah, i think i know why:

This: "from": -2400, (and the "to" field) are in mapblocks, not nodes and your coordinate would result somewhere around -38'000, far outside the world borders :/

I documented this here: https://github.com/minetest-mapserver/mapserver/blob/master/doc/config.md#layers but i think i have to place it somewhere more visible in the future.

In your case, this config should work:

"layers": [
	{
		"id": 0,
		"name": "Ground",
		"from": -1,
		"to": 10
	},
	{
		"id": 1,
		"name": "Sky",
		"from": 11,
		"to": 24
	},
	{
		"id": 2,
		"name": "BaseCave",
		"from": -150,
		"to": -144
	},
	{
		"id": 3,
		"name": "Caves",
		"from": -145,
		"to": -147
	}
],

Just divide the node-coordinates by 16 and you have the mapblock coordinates

[antevens]

Thanks!

That works perfectly and the documentation is clear, it's the user that's the problem :)

Perhaps inline comments or bounds checking with a warning might be the best way to go?
The lower example also has the from/to reversed in which case nothing is shown so if a check were to be added that might be another good thing to add to the check.