Hey all, I have a vector tile polygon source hosted in Mapbox Studio and an isochrone geojson generated using the isochrone api. I'm trying to use turf intersect to find a count of polygons within the isochrone, but getting
Unknown GeoJSON type: undefined because one of the data inputs is vector tiles. I found a question on this back in 2016, but looking for a current answer/resource that will help me learn a) whether I need to convert the vt to geojson and b) best method for doing this client side. Maybe the best answer is to just use a geojson source to begin with?
Has anyone done something like this?
@knownasilya By geojson spec polygon without hole like this:
{ "type": "Polygon",
"coordinates": [
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ]
]
}
and with hole:
{ "type": "Polygon",
"coordinates": [
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ],
[ [100.2, 0.2], [100.8, 0.2], [100.8, 0.8], [100.2, 0.8], [100.2, 0.2] ]
]
}
Attention: first array is bigest area
Check this two condition and do intersect.
{ "type": "Polygon",
"coordinates": [
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ]
]
}
and with hole:
{ "type": "Polygon",
"coordinates": [
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ],
[ [100.2, 0.2], [100.8, 0.2], [100.8, 0.8], [100.2, 0.8], [100.2, 0.2] ]
]
}
Attention: first array is bigest area
Check this two condition and do intersect.
Hi can anyone help as to why this dissolve example is not dissolving? http://jsfiddle.net/dejz01v4/1/
i'm wondering if there is a library like this https://www.npmjs.com/package/@turf/boolean-point-in-polygon
that instead of returning a boolean it returns the matching polygon
@benboughton1 Very strange, in source code dissolve using union . . .
I'm soooo confused by versioning - Is v7 the latest? this still seems to be an issue: Turfjs/turf#1800
Anyone experience this?
from the docs, it seems to be something that's obvious and widely known
"A buffer is an area defined by the bounding region determined by a set of points at a specified maximum distance from all nodes along segments of an object."
In practice, its a polygonal boundary drawn around a geometry of any type, with all edges at least N distance from the unbuffered geometry
PostGIS has a similar feature that has more documentation here: http://www.postgis.org/docs/ST_Buffer.html
Anyone looking to help an open source project ? For the last few years, I have been empowering people to map litter. https://github.com/OpenLitterMap/openlittermap-web is now open source
I am working on a wildfire tracking app and trying to get rid of ugly sliced, self intersecting polygons. Check it out here: firewild.netlify.app
Repo is here: https://github.com/nrhill1/firewild
Hi, I've noticed that when I generate a square grid, whether it's with degrees or radians, the cell dimensions don't match up:
> turf.squareGrid([28.225,27.925,29.275,29], .025 * Math.PI / 180, {units: 'radians'})
...
> turf.squareGrid([28.225,27.925,29.275,29], .025 * Math.PI / 180, {units: 'radians'}).features[0].geometry.coordinates
[
[
[ 28.226548620665543, 27.9375 ],
[ 28.226548620665543, 27.9625 ],
[ 28.25484328981876, 27.9625 ],
[ 28.25484328981876, 27.9375 ],
[ 28.226548620665543, 27.9375 ]
]
]As you can see, the latitudes are separated by the correct distance (.025) while the longitudes don't. The longitudes are not on the same grid as the provided bounding box. Is there an explanation for this? I've done a bunch of googling but haven't found any reasoning. Checking the source now...
https://github.com/Turfjs/turf/blob/v6.3.0/packages/turf-rectangle-grid/index.ts#L57 That's the issue. Hmmm, I wonder why this is there?
Well, that's not really the issue. But this is:
> turf.distance([28.225, 27.925], [29.275, 27.925], {units: 'degrees'})
0.9266538967022185
> 29.275-28.225
1.0499999999999972Is there an explanation for this? I guess I'll just gut rectangularGrid for my needs...
Hi everyone! ;)
I have a small - and probably silly - question. Is any way to get list of random point for a polygon? I tried to use this functions set: bbox => randomPoint => pointsWithinPolygon. randomPoint count is set to 50, but usually I get very low number of points within polygon (at most 5).
I have a small - and probably silly - question. Is any way to get list of random point for a polygon? I tried to use this functions set: bbox => randomPoint => pointsWithinPolygon. randomPoint count is set to 50, but usually I get very low number of points within polygon (at most 5).
const polygonBbox = bbox(poly);
const truncatedPoints = truncate(
randomPoint(pointsLimit, { bbox: polygonBbox }),
truncateOptions,
);
return pointsWithinPolygon(truncatedPoints, poly).features.map(getPointCoords);
Hi all, I have a multipolygon and I'd like to put markers on each area. If one of the areas is particularly large, I'd like to put a few markers on it, roughly evenly spread apart. But I can't figure out how to do the "roughly evenly spread apart" bit. It's like computing a centroid, but a distribution of sorts. I'm not sure what it's called, so I don't know what to search for. Any idea what I should look for?
Hey all! I have another question. I'm doing mapping with a lot of points near towns, and sometimes a point falls outside of the state I'm looking at. I can get a centroid for all of the towns and check the nearest centroid to the point, but I wonder if there is a way to find the nearest container, instead of depending on a centroid?
Maybe it's a dumb question?