Custom projection

<Slider bind:value={lat} min={-90} max={90} label="lat" />
<Slider bind:value={lon} min={-180} max={180} label="lon" />
<Slider
    bind:value={zoom}
    min={0.1}
    max={10}
    step={0.01}
    label="zoom" />
<Plot
    inset={5}
    projection={{
        type: ({
            width,
            height
        }: {
            width: number;
            height: number;
        }) =>
            geoOrthographic()
                .translate([width * 0.5, height * 0.5])
                .scale(width * 0.5 * zoom)
                .rotate([-lon, -lat])
    }}
    height={(w) => w}>
    <Graticule opacity={0.1} />
    <Geo
        data={countries}
        fill="currentColor"
        opacity={0.3}
        stroke="var(--svelteplot-bg)" />
</Plot>