nycplanning / labs-geojson2mvt Goto Github PK

Running geojson2mvt on a large region tends to crash with the javascript heap size limit being reached. I think something is leaking memory in there. Plot shows heapsize vs tile number. You can see the Garbage collection working but its not grabbing everything.

Not sure if this is an issue in geojson2mvt or one of the required libraries but investigating.

A bit revision will benefit users of older Node.js versions.

Would be great to have available as a shell command, for global install and quick usage from the command line.

See: https://developer.atlassian.com/blog/2015/11/scripting-with-node/#packaging-shell-commands

Maybe an issue with default setting of geojson-vt. Used your example but end up with all mvt's having file size 0 from z=15 and up.

Reading big files in node

I would like to generate mvt pyramids with your package for really big geojson file(2GB). It is not possible with fs.readFileSync, because of file size. How can I deal with this problem?
Is it possible to generate piramides for many geojson files? Or maybe I should use streams?

Is it use case for multiple layers? Should I cut geojson on many smaller?

Would you be open to accepting a pull request that changes the API slightly to support multiple layers? Something like

var fs = require('fs');
var geojson2mvt = require('geojson2mvt');
 
const busRoutes = './bus_routes.geojson';
const busStops = './bus_stops.geojson';
 
var options = {
  rootDir: 'tiles',
  bbox : [40.426042,-74.599228,40.884448,-73.409958], //[south,west,north,east]
  zoom : {
    min : 8,
    max : 18,
  },
  layers: {
    'layer0': JSON.parse(fs.readFileSync(busRoutes, "utf8")),
    'layer1': JSON.parse(fs.readFileSync(busStops, "utf8"))
  },
};
 
// build the static tile pyramid
geojson2mvt(options);

I could also make this in a backwards compatible way, if desired.

We should have the first argument be a geojson object, not a path to a geojson file. This will allow people to manipulate their data in javascript before passing it into geojson2mvt()

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