leaflet-virtual-grid
v1.0.7
Published
A lightweight DOM-less tile layer for Leaflet that can be used to query APIs with bounding boxes or center/radius as opposed to loading tiles.
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6,193
Readme
Leaflet Virtual Grid
You can use new VirtualGrid
to generate simple, cacheable, grids of L.LatLngBounds
objects you can use to query APIs. This lets you query APIs for smaller units and space and never make a call data in the same area twice.
Usage with Events
var vg = new VirtualGrid();
// listen for when new cells come into the view for the first time
vg.on("cellcreate", function(e){
console.log(e.type, e);
});
// listen for when cells reenter the view
vg.on("cellenter", function(e){
console.log(e.type, e);
});
// listen for when cells leave the view
vg.on("cellleave", function(e){
console.log(e.type, e);
});
// add the grid to the map
vg.addTo(map);
Usage as a Class
var MyGrid = new VirtualGrid.extend({
createCell: function(bounds, coords){
console.log('create cell', bounds, coords);
},
cellEnter: function(bounds, coords){
console.log('cell enter', bounds, coords);
},
cellLeave: function(bounds, coords){
console.log('cell leave', bounds, coords);
}
})
var thingWithGrid = new MyGrid().addTo(map);
Options
var vg = new VirtualGrid({
cellSize: 512,
updateInterval: 150
});
updateInterval
How often to update the grid. Defaults to 150
cellSize
How big each cell is in pixels. Defaults to 512
Example
Here is what the grid looks like under the hood...
Each rectangle would represent a call to an API or query to a data source. You would only make one request per cell so you not make repeat calls to areas like requesting all the data in a map view when a user performs a small pan.
Credit
Most of this code is based on L.Grid
from https://github.com/Leaflet/Leaflet/commit/670dbaac045c7670ff26198136e440be9c2bb3e5.