vector-tile-query

vector-tile-query 1.2.0
=======================

vector-tile-query allows you to query Mapbox Vector Tiles and return data values from these tiles. This module consists of one main function, and two utility / helper functions.

$3

Parses a Vector Tile protobuf and queries a layer for a a number of fields based on a series of lat, lngs points

#### Input

* pbuf: vector tile (pbuf)
* tileInfo: tile Z,X,Y ('tileinfo: {z:,x:,y:}')
* queryPoints: array of lat, lngss ([[lat,lng],[lat,lng]...])
* pointIDs: array of point IDs that correspond to order of query lat,lngs ([0,1,2...])
* options: options for query:
* layer: layer within the tile source to query. Example: contour
* fields: array of fields within the layer to return data for. Example [ele]
* interpolate (optional): whether or not to interpolate between closest two features. Example false. Default true
* callback: function(err,data) {...} to call upon completion of query

#### Output

Array (with one record per input lat,lng) of values:
``
[
{
id: ,
latlng: { lat: , lng: },
: ,
:
},
...
]
`

$3

Given a set of lat,lng points and a zoom level, finds what tiles to load, loads these tiles asynchronously (using a defined function), splits query lat, lngss out per tile, and assigns these a sequential ID (based on input order)

#### Input

* queryPoints: array of lat, lngss ([[lat,lng],[lat,lng]...])
* zoom: zoom level of tiles to query
* loadFunction: function to load tiles / should return a pbuf
* callback: function(err,data) {...} to call upon completion

#### Output
Array of "tile objects" with tile zxy, query points within that tile, ids of these points, and vector tile pbufs.
`
[
{
zxy: { z: , x: , y: },
points: [ [lat,lng], [lat,lng], ... ],
pointIDs: [ 0, 1, ... ],
data:
}
...
]
`

$3

Helper function to asynchronously query (using queryTile (given a set of "tile objects") and return sorted values (based on input order / input point ids).

#### Input

* dataArr: array of "tileObjects" as described above - one record for each tile that will be queried
* options: options as described above in queryTile
* callback: function(err,data) {...} to call upon completion

#### Output

Array (with one record per input lat,lng) of values:
`
[
{
id: ,
latlng: { lat: , lng: },
: ,
:
},
...
]
`

$3


`
git clone https://github.com/mapbox/vector-tile-query.git
npm install
``