Update a Mapbox layer by zoom level when loading geojson - r

Question

Very similar to this tutorial, I would like to create a MapBox map that at a zoomed out level shows regions (labelled Pcode in my data), but once zoomed it switched to a district level (labelled Name). Ideally both these layers would be part of a single geojson shapefile though that can be loaded from an external source (https://raw.githubusercontent.com/Laurent-Smeets-GSS-Account/geojsons/main/geojsons_files/Districts_261_simplified.json). my questions are
how can I format the geojson in such a way that is possible (in R)? (Maybe it is necessary to combine the district polygons into new region polygons and save a seperate geojson file with these regions that gets loaded at another zoom level?)
how do I load the data into Mapbox to make it switch at a certain zoom level?
I am using this example on how to load the code
mapboxgl.accessToken = 'MY TOKEN';
// Create a new map.
const map = new mapboxgl.Map({
container: 'map',
// Choose from Mapbox's core styles, or make your own style with Mapbox Studio
style: 'mapbox://styles/mapbox/streets-v12',
center: [-100.04, 38.907],
zoom: 3
});
map.on('load', () => {
// Add a source for the state polygons.
map.addSource('states', {
'type': 'geojson',
'data': 'https://raw.githubusercontent.com/Laurent-Smeets-GSS-Account/geojsons/main/geojsons_files/Districts_261_simplified.json'
});
// Add a layer showing the state polygons.
map.addLayer({
'id': 'states-layer',
'type': 'fill',
'source': 'states',
'paint': {
'fill-color': 'rgba(200, 100, 240, 0.4)',
'fill-outline-color': 'rgba(200, 100, 240, 1)'
}
});
// When a click event occurs on a feature in the states layer,
// open a popup at the location of the click, with description
// HTML from the click event's properties.
map.on('click', 'states-layer', (e) => {
new mapboxgl.Popup()
.setLngLat(e.lngLat)
.setHTML(e.features[0].properties.Name)
.addTo(map);
});
// Change the cursor to a pointer when
// the mouse is over the states layer.
map.on('mouseenter', 'states-layer', () => {
map.getCanvas().style.cursor = 'pointer';
});
// Change the cursor back to a pointer
// when it leaves the states layer.
map.on('mouseleave', 'states-layer', () => {
map.getCanvas().style.cursor = '';
});
});

Answer 1

You can combine both sets of features into one GeoJSON FeatureCollection, just be sure to add some property that you can filter on, like:
...
{
type: 'Feature',
geometry: {...},
properties: {
type: 'district'
}
}
...
When you load the data, add one source, and two layers. Each layer should have a filter attribute so that only the features of a certain type show in that layer. Make sure one has its visibility set to none when the map first loads.
map.addLayer({
...,
layout: {
visibility: 'none'
},
filter: ['==', 'type', 'district']
});
map.addLayer({
...,
filter: ['==', 'type', 'pcode']
});
Then you can follow the same example you posted, and toggle the visibility on zoom.