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I have a project where I need to save polygons to a database. I found that you can get the coordinates array from a feature using: feature.getGeometry().getCoordinates(). This returns an array of all the coordinate points. Is this the bare minimum I have to save to a database in order to redraw this feature from scratch again later?

I don't need a PostGIS database to save all of the other feature data. The other information is not needed for my application. All I need is too redraw the exact same feature that was saved into the database.

I also only use EPSG:3857. But I would also save this with a feature just to be sure.

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    If you have only polygons and you don't care about the style and your CRS is always EPSG:3857, then coordinates are enough. See polygon geometry creation method: openlayers.org/en/latest/apidoc/… – TomazicM Jun 9 at 9:30
  • @TomazicM Thanks for the answer! – Stephen Jun 9 at 10:42
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You can easily dump Openlayers Layer to GeoJSON saving not only geometry but all the attributes as well. GeoJSON can be store anywhere, as a file or in a database.

import GeoJSON from 'ol/format/GeoJSON.js'

const format = new GeoJSON({ featureProjection: 'EPSG:3857' });
const layers = map.getLayers(); // map is 'ol/Map' object
const source = layers.item(0).getSource(); // grab first layer
const features = source.getFeatures();
const json = format.writeFeatures(features);

// dump json to file or save in database

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