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A TileDao provides access to raster tiles stored in a GeoPackage tile table. Each tile is identified by its column, row, and zoom level. Obtain a TileDao from an open GeoPackage. 
const tileDao = geoPackage.getTileDao('imagery');
TileDao extends UserDao, so generic row operations such as queryForAll(), create(), update(), and deleteById() are also available.

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Creating a TileDao

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getTileDao()

Call this on an open GeoPackage to get a TileDao for the named tile table. 
geoPackage.getTileDao(tableName: string): TileDao

const tileDao = geoPackage.getTileDao('world_imagery');

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Querying tiles

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queryForTile()

Returns the TileRow at the given tile grid coordinates, or null if no tile exists at that location. 
queryForTile(column: number, row: number, zoomLevel: number): TileRow
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column
number
required
Tile column index (x-axis).
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row
number
required
Tile row index (y-axis).
​
zoomLevel
number
required
Zoom level of the requested tile.
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return
TileRow | null
The matching tile row, or null if not found.
const tile = tileDao.queryForTile(3, 2, 5);
if (tile) {
  const bytes = tile.getTileData();
}

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queryForTiles()

Returns a TileResultSet of all tiles at the specified zoom level. 
queryForTiles(zoomLevel: number): TileResultSet
​
zoomLevel
number
required
Zoom level to query.
​
return
TileResultSet
Result set that should be closed after use.
const results = tileDao.queryForTiles(4);
try {
  while (results.moveToNext()) {
    const row = results.getRow();
    console.log(row.getTileColumn(), row.getTileRow(), row.getTileData()?.length);
  }
} finally {
  results.close();
}

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queryByTileGrid()

Returns a TileResultSet for all tiles within the given TileGrid at a zoom level. Use this for range queries across columns and rows. 
queryByTileGrid(tileGrid: TileGrid, zoomLevel: number, orderBy?: string): TileResultSet
​
tileGrid
TileGrid
required
A TileGrid specifying min/max column and min/max row bounds.
​
zoomLevel
number
required
Zoom level to query.
​
orderBy
string
Optional SQL ORDER BY expression.
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return
TileResultSet | null
Result set, or null if the tile grid is null.
import { TileGrid } from '@ngageoint/geopackage';

// Columns 2–4, rows 1–3 at zoom 5
const grid = new TileGrid(2, 1, 4, 3);
const results = tileDao.queryByTileGrid(grid, 5);

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queryForTilesInColumn()

Returns a TileResultSet of all tiles in a specific column at a zoom level. 
queryForTilesInColumn(column: number, zoomLevel: number): TileResultSet

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queryForTilesInRow()

Returns a TileResultSet of all tiles in a specific row at a zoom level. 
queryForTilesInRow(row: number, zoomLevel: number): TileResultSet

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deleteTile()

Deletes the tile at the specified coordinates. Returns the number of rows deleted. 
deleteTile(column: number, row: number, zoomLevel: number): number

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Zoom level helpers

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getMinZoom()

Returns the minimum zoom level present in this tile table. 
getMinZoom(): number

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getMaxZoom()

Returns the maximum zoom level present in this tile table. 
getMaxZoom(): number

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getZoomLevels()

Returns an array of all zoom levels that have a corresponding TileMatrix entry. 
getZoomLevels(): number[]

const zooms = tileDao.getZoomLevels(); // [0, 1, 2, 3, 4, 5]

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getTileMatrix()

Returns the TileMatrix for a specific zoom level, or null if none exists. 
getTileMatrix(zoomLevel: number): TileMatrix
​
zoomLevel
number
required
Zoom level to look up.
​
return
TileMatrix | null
The tile matrix describing tile dimensions and pixel sizes at this zoom, or null.

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getTileMatrixSet()

Returns the TileMatrixSet that defines the spatial extent and SRS for the entire tile table. 
getTileMatrixSet(): TileMatrixSet

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getTileGrid()

Returns a TileGrid representing the full column/row range at the given zoom level, or null. 
getTileGrid(zoomLevel: number): TileGrid

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countAtZoomLevel()

Returns the number of tiles stored at a specific zoom level. 
countAtZoomLevel(zoomLevel: number): number

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TileRow

A TileRow is a single row returned from a tile table query, containing the encoded image bytes and the tile’s position.

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getTileData()

Returns the raw encoded image bytes for this tile. 
getTileData(): Buffer | Uint8Array
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return
Buffer | Uint8Array
The raw image bytes (typically PNG or JPEG).

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getTileDataImage()

Decodes the tile bytes and returns a Promise<GeoPackageImage>. 
getTileDataImage(): Promise<GeoPackageImage>

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getTileColumn()

Returns the tile column index (x position) for this row. 
getTileColumn(): number

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getTileRow()

Returns the tile row index (y position) for this row. 
getTileRow(): number

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getZoomLevel()

Returns the zoom level of this tile. 
getZoomLevel(): number

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getId()

Returns the primary key value of this row. 
getId(): number

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Full example

import { GeoPackageManager } from '@ngageoint/geopackage';

const geoPackage = await GeoPackageManager.open('./tiles.gpkg');
const tileDao = geoPackage.getTileDao('world_imagery');

console.log('Zoom levels:', tileDao.getZoomLevels());
console.log('Min zoom:', tileDao.getMinZoom(), 'Max zoom:', tileDao.getMaxZoom());

// Retrieve a specific tile
const tile = tileDao.queryForTile(0, 0, 0);
if (tile) {
  const bytes = tile.getTileData();
  console.log('Tile size (bytes):', bytes?.length);
  console.log('Position:', tile.getTileColumn(), tile.getTileRow(), 'z:', tile.getZoomLevel());
}

geoPackage.close();

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