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GeoPackageLoader

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From-v3.0

caution

The GeoPackageLoader depends on the sql.js npm module which has caused issues with certain JavaScript bundlers. It is recommended that you do your own tests before using the GeoPackageLoader in your project.

GeoPackage loader

LoaderCharacteristic
File Extension.gpkg
File TypeBinary
File FormatGeoPackage
Data FormatGeometry
Supported APIsload, parse
Decoder TypeAsynchronous
Worker Thread SupportNo

Usage

To load all tables in a geopackage file as GeoJSON:

import {GeoPackageLoader, GeoPackageLoaderOptions} from '@loaders.gl/geopackage';
import {load} from '@loaders.gl/core';
import {Tables, ObjectRowTable, Feature} from '@loaders.gl/schema';

const optionsAsTable: GeoPackageLoaderOptions = {
geopackage: {
shape: 'tables',
sqlJsCDN: 'https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.5.0/'
}
};
const tablesData: Tables<GeoJSONTable> = await load(url, GeoPackageLoader, optionsAsTable);

To load a specific table named feature_table in a geopackage file as GeoJSON:

const optionsAsGeoJson: GeoPackageLoaderOptions = {
geopackage: {
shape: 'geojson',
table: 'feature_table',
sqlJsCDN: 'https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.5.0/',
}
};

const geoJsonData: GeoJSONTable = await load(url, GeoPackageLoader, optionsAsGeoJson);

Options

OptionTypeDefaultDescription
options.shapeString'tables' | 'geojson-table'Output format.
options.tableStringN/Aname of table to load
geopackage.sqlJsCDNString'https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.5.0/'CDN from which to load the SQL.js bundle. This is loaded asynchronously when the GeoPackageLoader is called on a file.

Output

The GeoPackageLoader currently loads all features from all vector tables.

  • If options.gis.format is 'tables' (the default):

    Returns Tables<ObjectRowTable>, an object whose .tables member is an array of objects with name and table keys. Each name member holds the name of the GeoPackage table name, and each .table member holds a Table instance. The Table.data member is an array of GeoJSON features, while Table.schema describes the schema types of the original Sqlite3 table.

  • If options.gis.format is 'geojson':

    Returns Record<string, Feature[]>, an object mapping from table name to an array of GeoJSON features. The Feature type is defined in @loaders.gl/schema.

Remarks

  • options.geopackage.sqlJsCDN: As of March 2022, SQL.js versions 1.6.0, 1.6.1, and 1.6.2 were tested as not working.

Future Work

  • Select a single vector layer/table to load. This could would fit well in the two-stage loader process, where the first stage reads metadata from the file (i.e. the list of available layers) and the second stage loads one or more tables.
  • Binary and GeoJSON output. Right now the output is GeoJSON-only, and is contained within an object mapping table names to geometry data. This is the same problem as we discussed previously for MVT, where with GeoPackage especially it's decently likely to only desire a portion of the layers contained in the file.