Example: Create a new GeoPackage

[bertday]

Hello — thank you for this awesome library!

I am a new user and would like to know how to create a new, empty GeoPackage. I'm having some trouble hunting down an example of how to do this. I see there a method GeoPackageAPI.create(), but it's not entirely clear to me how to use it. When I run this code:

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

(async () => {
  const gpkg = await GeoPackageAPI.create('/Users/me/test.gpkg');
})(); 

I get Error: Unable to initialize canvas.

Having a minimal example of this would be super helpful — thank you!

[danbritt]

In the docs for using it with node, it says you have to import setCanvasKitWasmLocateFile and then use it and return the path to the file like this

setCanvasKitWasmLocateFile(file => 'path/to/geopackage/dist/canvaskit/' + file);

Your example would change to:

import { GeoPackageAPI, setCanvasKitWasmLocateFile } from '@ngageoint/geopackage';

(async () => {
  setCanvasKitWasmLocateFile(file => 'path/to/geopackage/dist/canvaskit/' + file);
  const gpkg = await GeoPackageAPI.create('/Users/me/test.gpkg');
})();

However, I have done this and it still doesn't work. I still get Error: Unable to initialize canvas. So I'm not sure if something is broken or what. I have even returned the full absolute path to the canvaskit.wasm file and it still says it can't initialize.

[danbritt]

So it looks like you don't need the canvas stuff if all you want is to create a geopackage with geojson features in it, which is what I needed to do. You can just make it think it's initialized by using CanvasKitCanvasAdapter.initialized = true;. Here is an example:

index.mjs

import geoJson from './geoJson.json' assert { type: 'json' };
import {
    GeoPackageAPI,
    FeatureColumn,
    GeometryColumns,
    GeoPackageDataType,
    BoundingBox,
    GeometryType,
    CanvasKitCanvasAdapter,
} from '@ngageoint/geopackage';

(async () => {
	// Fake that the canvas is initialized, since it doesn't seem to initialize in a node environment
	CanvasKitCanvasAdapter.initialized = true;
	
	
	const gpkg = await GeoPackageAPI.create('./test.gpkg');
	
	// Check GeoPackageDataType enum for these values
	let fields = [
		{ name: 'ID', typeName: 'TEXT' },
		{ name: 'Count', typeName: 'INT' },
		{ name: 'ItemNumber', typeName: 'TEXT' }
	];
	
	let geomTypeName = 'POINT'; // Check GeometryType enum for these values 
	let tableName = 'MyLayer';
	let srId = 4326;
	let geomColName = 'SHAPE';
	let geomTypeId = GeometryType.fromName(geomTypeName);
	
	let geometryColumns = new GeometryColumns();
	geometryColumns.table_name = tableName;
	geometryColumns.column_name = geomColName;
	geometryColumns.geometry_type_name = geomTypeName;
	geometryColumns.z = 2;
	geometryColumns.m = 2;
	
	let columns = [];
	// Need to create an int auto increment ID for the sqlite db. Not sure if it can use guids
	columns.push(FeatureColumn.createPrimaryKeyColumn(0, 'NID', true));
	columns.push(
		FeatureColumn.createGeometryColumn(
			1,
			'SHAPE',
			geomTypeId,
			true,
			null
		)
	);
	let colIndex = 2;
	
	// Add other columns
	for (let field of fields) {
		let fieldTypeId = GeoPackageDataType.fromName(field.typeName);

		columns.push(
			FeatureColumn.createColumn(
				colIndex,
				field.name,
				fieldTypeId,
				false,
				null
			)
		);
		colIndex++;
	}

	let bbox = new BoundingBox(-180, 180, -90, 90);
	
	gpkg.createFeatureTable(
		tableName,
		geometryColumns,
		columns,
		bbox,
		srId
	);
	
	await gpkg.addGeoJSONFeaturesToGeoPackage(
		geoJson.features,
		tableName
	);
	
	gpkg.close();
	
})();

geoJson.json

{
   "type":"FeatureCollection",
   "features":[
      {
         "type":"Feature",
         "geometry":{
            "type":"Point",
            "coordinates":[
               -84.336016,
               35.906206
            ]
         },
         "properties":{
            "ID":"97bbf51e-0262-4439-a217-00b3dc282bdc",
            "Count":2,
            "ItemNumber":"Item1"
         }
      },
      {
         "type":"Feature",
         "geometry":{
            "type":"Point",
            "coordinates":[
               -84.386671,
               35.943449
            ]
         },
         "properties":{
            "ID":"9642775c-3dee-4906-8411-8040e9f3329c",
            "Count":1,
            "ItemNumber":"Item2"
         }
      },
      {
         "type":"Feature",
         "geometry":{
            "type":"Point",
            "coordinates":[
               -84.301242,
               35.943728
            ]
         },
         "properties":{
            "ID":"022d12fa-f156-4ca4-9713-e5df67c078ee",
            "Count":4,
            "ItemNumber":"Item3"
         }
      },
      {
         "type":"Feature",
         "geometry":{
            "type":"Point",
            "coordinates":[
               -84.360066,
               35.950069
            ]
         },
         "properties":{
            "ID":"98841440-789b-4441-9640-b00cc1405e75",
            "Count":8,
            "ItemNumber":"Item4"
         }
      },
      {
         "type":"Feature",
         "geometry":{
            "type":"Point",
            "coordinates":[
               -84.317448,
               35.914034
            ]
         },
         "properties":{
            "ID":"f2af3539-697a-454a-a484-0b8978556f4e",
            "COUNT":11,
            "ItemNumber":"Item5"
         }
      }
   ],
   "totalFeatures":5,
   "numberMatched":5,
   "numberReturned":5,
   "timeStamp":"2023-01-19T04:19:42.308Z",
   "crs":{
      "type":"name",
      "properties":{
         "name":"urn:ogc:def:crs:EPSG::4326"
      }
   }
}

These are the resources I used to figure this out:

Example: https://github.com/ngageoint/geopackage-csv-js/blob/main/index.ts

Useful Docs:
https://ngageoint.github.io/geopackage-js/api/modules/GeometryType.html
https://ngageoint.github.io/geopackage-js/api/enums/GeometryType.html
https://ngageoint.github.io/geopackage-js/api/modules/GeoPackageDataType.html
https://ngageoint.github.io/geopackage-js/api/enums/GeoPackageDataType.html
https://ngageoint.github.io/geopackage-js/api/classes/GeometryColumns.html
https://ngageoint.github.io/geopackage-js/api/classes/FeatureColumn.html
https://ngageoint.github.io/geopackage-js/api/classes/GeoPackage.html