Extract 2500 geoJSON polygons to map flyers

Question

I searched but cannot find a solution.

I have a 170 MB GeoJSON file. It contains about 2500 polygons. Somehow I need to display it on the flyer card. Obviously, in this amount I have no chance.

What will be the easiest way to visualize this data? Can I create a complete transparent png that can simply be visualized on a world map. The huge size is due to the complexity and number of polygons. At the moment, I do not need this to be interactive.

Thanks Brian

Answer 1

The easiest way is to create your own map tiles based on this data. There are several ways to achieve this, but I suggest you use TileMill . It is free and very easy to use. So basically you would:

• Use TileMill and specify the GeoJSON file as the data source

• Customize the map display (e.g. polygon color) with a special CSS-like language inside TileMill

• Creating Fragments

• Download the new TileLayer to the Leaflet map that links to your files

I actually wrote a tutorial some time ago that uses .shp instead of GeoJson, but should be pretty similar:

http://build-failed.blogspot.pt/2012/03/custom-map-tiles-part-2-tilemill.html

Answer 2

I can not argue with the recommendation of psousa. For a simple presentation, TileMill is a great idea.

However, if you want to overlay your polygons on another card, I think the only way is to use Mike Bostock TopoJSON and D3.

TopoJSON Home: https://github.com/mbostock/topojson/wiki

An example on the scale you're talking about: http://bl.ocks.org/mbostock/4206573

You will need to inspect Mike's great examples on github to see how to combine the flyer with the D3 overlay.

I am doing this successfully with hundreds of complex polygons. There was no need to break into thousands ... yet.

Answer 3

There is also geojson-vt , which apparently can for shingles without a server on the fly - after a short load time.

Answer 4

Just one modest offer. I successfully loaded 10,000+ polygons and attribute queries, deploying my own Geoserver and PostgreSQL DB + PostGIS instance and creating WMS (not WFS), as you can see in the image.

But this is impractical to implement, especially if the geoisone data is the source (and only) data

In this regard, I would answer the second psousa question to use TileMill.