Geovisualization Developer's Guide

H.datalens.RasterLayer. Options

Type Definition Summary

Defines data processing and rendering options for RasterLayer .

Type Definition Description

The initial step of rendering is to split the tile data by rows, where each row represents a bucket. By default this step is processed with H.datalens.RasterLayer.defaultDataToRows . This behavior can be changed by defining the dataToRows callback. To collect the rows for a tile including buffer, the rows must be translated to H.datalens.RasterLayer.TilePoint . This translation must be specified with the rowToTilePoint callback. The final rendering on the tile canvas must be defined in renderTile .

Property Details

dataToRows : { function( H.datalens.Service.Data , H.datalens.QueryTileProvider.X , H.datalens.QueryTileProvider.Y , H.datalens.QueryTileProvider.Zoom ) : Array.< H.datalens.RasterLayer.Row > } [optional]

Defines how the input tile data is split by rows. You can specify this callback to define client-side aggregation and filtering. This callback is called for each tile.

rowToTilePoint : { function( H.datalens.RasterLayer.Row , H.datalens.RasterLayer .X , H.datalens.RasterLayer .Y ) : H.datalens.RasterLayer.TilePoint }

Defines how the row is translated to the H.datalens.RasterLayer.TilePoint . This callback is called for each row that is returned from dataToRows .

buffer : { function( H.datalens.QueryTileProvider.Zoom ) : number } [optional]

Defines the buffer as a function of the zoom level. The buffer is a value (in pixels) that defines an extra area around each tile to capture data points from. This is done to avoid drawing edges between tiles. For example, if data points represented with circles with a maximum radius of 10 pixels, then the buffer must be 10 pixels.

renderTile : { function( Array.< H.datalens.RasterLayer.TilePoint > , HTMLCanvasElement , H.datalens.QueryTileProvider.Zoom ) } [optional]

Defines how tile data is represented on a canvas. Input points for each tile are collected with respect to the buffer. For progressive rendering this callback may be called more than once for the tile.

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