Zoom levels 1 and 2 produce incorrect tile URLs when using non-mercator projections

[simonmckenzie]

Describe the bug

I am experiencing a bug where zoom levels 1 and 2 are producing ESRI tile URLs that look like this:

https://<server>/arcgis/rest/services/<...>/MapServer/tile/r/438/307
https://<server>/arcgis/rest/services/<...>/MapServer/tile/s/438/307

Note the "r" and "s" in place of the zoom levels.

This is caused by changes made in #1411, where _lodMap is set to the literal string "crs":

esri-leaflet/src/Layers/TiledMapLayer.js

Lines 190 to 191 in 590cb47

	// if the projection is WGS84, or the developer is using Proj4 to define a custom CRS, no action is required
	this._lodMap = "crs";

When getTileUrl runs, it will index into this string:

esri-leaflet/src/Layers/TiledMapLayer.js

Lines 89 to 94 in 590cb47

	// try lod map first, then just default to zoom level
	z:
	this._lodMap && this._lodMap[zoom] !== undefined
	? this._lodMap[zoom]
	: zoom,
	},

For zoom level 1, this produces the "r" ("crs"[1] == "r"), and for zoom level 2, this produces the "s" ("crs"[2] == "s").

Reproduction

https://jsbin.com/fenugafuha/edit?html,output

You can see the "r" in the tile URLs being requested. Once you zoom in past level 2, the tile URLs become correct.

System Info

esri-leaflet: 3.0.19
leaflet: 1.9.4

[simonmckenzie]

Hi @gavinr-maps and @patrickarlt - hopefully this issue is clear to you (tagging you because you were involved in #1411)

[gavinr-maps]

Thanks for reporting this. I've reviewed your replication case and it definitely seems like an oversight/issue with #1411.

I have a potential fix here: #1417 ... would you be able to test that out to see if it resolves your issue?

[simonmckenzie]

Thanks for looking into this @gavinr-maps - yes, this resolves my issue.