MapKit JS TileOverlay tile size

Question

Created Nov ’20

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I've added a tile overlay on a MapKit JS map, but I cannot find any way to set the tile size for the overlay.

The tiles do appear but they are not sharp on a retina display and now appear blurry. The text on them is too large and should be half the size it is now.

I have tried looking for any kind of scale, retina, tileSize or similar parameter on mapkit, map and TileOverlay objects. There must be a way to do this, right?

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Answer 1

Frameworks Engineer OP

Apple

Dec ’20

See mapkit.TileOverlay.

The template string must be in the format: https://myserver/tile?x={x}&y={y}&z={z}&scale={scale}. MapKit JS replaces the x, y, z, and scale values depending on the displayed map region and screen resolution, then loads an image from that URL.

Setting up the right scale should help.

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Answer 2

pasi OP

Dec ’20

But wouldn't this require that the API supports this scale query parameter? I'm using a public API, which I have no control over, and the API does not recognise this parameter or any other scale argument like @2x etc.

Wouldn't the tile size need to be configured for the TileOverlay object itself? Now it seems to default to 512x512, and I would need to change that size to make the PNG tiles appear sharper, right?

I just checked and the map tile API seems to have tile dimensions of 256x256, which would appear blurry if drawn at 512x512.

In UIKit, it is possible to set the tileSize for a MKTileOverlay, which solves this problem for my native app.
https://developer.apple.com/documentation/mapkit/mktileoverlay

var tileSize: CGSize
The size (in pixels) of your tile images.

The MapKit JS TileOverlay object does not offer a similar property, as far as I can see
https://developer.apple.com/documentation/mapkitjs/mapkit/tileoverlay/2974035-mapkit_tileoverlay

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