com.conveyal.r5.analyst.cluster

Class TimeGrid

java.lang.Object

com.conveyal.r5.analyst.cluster.TimeGrid

public class TimeGrid
extends Object

Grid for recording travel times, which can be written to flat binary output This is similar to com.conveyal.r5.analyst.Grid, but it uses ints for the pixel values, and allows multiple values per pixel. * Time grids look like this: Header (ASCII text "TIMEGRID") (note that this header is eight bytes, so the full grid can be mapped into a Javascript typed array if desired) Version, 4-byte integer (4 byte int) Web mercator zoom level (4 byte int) west (x) edge of the grid, i.e. how many pixels this grid is east of the left edge of the world (4 byte int) north (y) edge of the grid, i.e. how many pixels this grid is south of the top edge of the world (4 byte int) width of the grid in pixels (4 byte int) height of the grid in pixels (4 byte int) number of values per pixel (repeated 4-byte int) values of each pixel in row major order. Values are not delta coded here.

Field Summary

Fields

Modifier and Type	Field and Description
static int	HEADER_SIZE The offset to get to the data section of the access grid file.
static org.slf4j.Logger	LOG
int	nValues

Constructor Summary

Constructors

Constructor and Description
TimeGrid(int zoom, int west, int north, int width, int height, int nValuesPerPixel) Create a new in-memory access grid writer for a width x height x nValuesPerPixel 3D array.

Method Summary

Modifier and Type	Method and Description
boolean	anyCellReached()
void	setTarget(int targetIndex, int[] pixelValues)
void	writeGeotiff(OutputStream out, AnalysisTask request) Write this grid out in GeoTIFF format.
void	writeGridToDataOutput(DataOutput dataOutput) Write the grid to an object implementing the DataOutput interface.
PersistenceBuffer	writeToPersistenceBuffer() Write the grid out to a persistence buffer, an abstraction that will perform compression and allow us to save it to a local or remote storage location.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

public static final org.slf4j.Logger LOG

HEADER_SIZE

public static final int HEADER_SIZE

The offset to get to the data section of the access grid file. The gridType string amounts to 2 ints.

nValues

public final int nValues

Constructor Detail

TimeGrid

public TimeGrid(int zoom,
                int west,
                int north,
                int width,
                int height,
                int nValuesPerPixel)

Create a new in-memory access grid writer for a width x height x nValuesPerPixel 3D array.

Method Detail

setTarget

public void setTarget(int targetIndex,
                      int[] pixelValues)

writeToPersistenceBuffer

public PersistenceBuffer writeToPersistenceBuffer()

Write the grid out to a persistence buffer, an abstraction that will perform compression and allow us to save it to a local or remote storage location.

writeGridToDataOutput

public void writeGridToDataOutput(DataOutput dataOutput)

Write the grid to an object implementing the DataOutput interface. TODO maybe shrink the dimensions of the resulting timeGrid to contain only the reached cells.

writeGeotiff

public void writeGeotiff(OutputStream out,
                         AnalysisTask request)

Write this grid out in GeoTIFF format. If an analysis task is supplied, add metadata to the GeoTIFF explaining what scenario it comes from.

anyCellReached

public boolean anyCellReached()

Returns:

true if the search reached any destination cell, false if it did not reach any cells. No cells will be reached when the origin point is outside the transport network. Some cells will still be reached via the street network when we are outside the transit network but within the street network.