Adding projection control and map instance logic #132
Conversation
| /** | ||
| * Returns whether a globe projection is currently being used | ||
| */ | ||
| isGlobeprojection(): boolean { |
| ## Field of view (FOV) | ||
| The internal camera has a default vertical field of view [*(wikipedia)*](https://en.wikipedia.org/wiki/Field_of_view) of a wide ~36.86 degrees. In globe mode, such a large *FOV* reduces the amount of the Earth that can be seen at once and exaggerates the central part, comparably to a fisheye lens. In many cases, a narrower *FOV* is preferable. Here is how to update if: | ||
|
|
||
| ```ts | ||
| // Ajust de FOV, with values from 1 to 50 | ||
| map.transform.setFov(10); | ||
| map.redraw(); | ||
| ``` | ||
| > 📣 *__Note:__* with the Mercator projection, it is possible to set a FOV of `0`, which yields a true orthographic projection [*(wikipedia)*](https://en.wikipedia.org/wiki/Orthographic_projection), but the globe projection does not allow this. | ||
|
|
||
| Here is a table of FOV comparison: | ||
| | 01° | 10° | 20° | 30° | 40° | 50° | | ||
| | :--------: | :-------: |:-------: |:-------: |:-------: |:-------: | | ||
| |  |  |  |  |  |  | | ||
|
|
There was a problem hiding this comment.
I'm thinking whether this is not too specific and maybe does not need to be documented directly in the readme? (Especially since it adds several megabytes of data to the repo.)
There was a problem hiding this comment.
Also, there is now a public method to adjust the FoV nicely: maplibre/maplibre-gl-js@d3f2bca
| > 📣 *__Note:__* Terrain is not fully compatible with the globe projection yet so it's better to disable it at low zoom level (from afar) and to choose the Mercator projection at higher zoom level (from up close). | ||
|
|
There was a problem hiding this comment.
Looks like this is getting fixed soon: maplibre/maplibre-gl-js#4977
There was a problem hiding this comment.
Kinda, yes, but there's a few gotchas that'll persist even after my PR is in, that could justify keeping the recommendation as is.
There's still an issue with the poles on the globe if terrain is active, which often will be visible at low zoom levels. Disabling terrain from the globe will make it look better. - maplibre/maplibre-gl-js#4984.
There's not support for fog on the globe yet with terrain, even after the transition to mercator at high zoom levels - due to the way it's disabled, switching to mercator projection will allow the fog to render at high zoom. Tickets here.
There was a problem hiding this comment.
Thanks a lot for the advice @birkskyum !
This is adding the projection control as well as Map class methods to address the projection change in an easier and more complete way than Maplibre
This also include the readme documentation about projections