Topojson for polygons

[manubb]

Topojson for polygons

[manubb]

Hi.
It is possible that i'm using topojson a bit weirdly (it's been a while and i do not remember clearly).
However, the demos use Leaflet default projection which expects 4326 coords.
The example you are giving use d3.geo.albersUsa projection so bad results can be expected when using Leaflet default projection.

Can you give me a topojson sample (using 4326 coords) so that i can have a look?

[pere]

thanks for this fast answer

I am not sure the json i sent you is on Albers, I think is transforming to Albers from a spherical (geographical) coordinates, that is 4326... but I have never been good on projections
link

In any case here, on the EU comission official webpage can download different Topojson polygonal layers at different projections, including 4326. I cannot send here any example JSON, please download from the site.

I send also a screenshot of my result with one of these json. Of course I had to change a few things on code to generate it, but with this code and your french topojson it works. So, should work for others topojsons...

I think the plugin has a great potential, dreaming on creating color transitions on polygons on changing various parameters... any help appreciated

I suggest to add as base layer a grey map (see below), because maybe generated (weird) polygons are not very visible.

 var grayLayer =L.tileLayer('https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}{r}.png', {
  attribution: '&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a> &copy; <a href="https://carto.com/attributions">CARTO</a>',
  subdomains: 'abcd',
  maxZoom: 19
}).addTo(map);

[manubb]

I think you are right for the coordinate system of d3 demo.
I have added a basic demo to display the US states:
https://manubb.github.io/Leaflet.PixiOverlay/simple-topojson.html
The sources are in the doc directory. Hope this will help you.

[pere]

This is great! thanks a lot