A few questions and answers about the last posts

I have had a few questions about TWKB and the websocket DEMO

When does the geoemtries actually load?
It is not obvious when the geoemtries actually gets loaded from the server to the browser.

That happens first time you click a layer. Then the geometries are streamed row by row via websocket to the browser which parses the geometry and adds it to the map, also geometry by geometry. Then if you switch off a layer and back again it is just loaded from Leaflet internally.

Can TWKB handle more than 2 dimmensions
Yes, TWKB can handle up to 7 dimmensions.

Can this websocket approach be used for writing back to the database?
Yes that is easy to implement. Just send the geometry back to nodejs with ws.send(), and insert it to the database. There is no function to import from TWKB into PostGIS. That is no big thing to write, but I don’t think there is the same performance need when posting back to the database, since that will be one or two geometries, not thousands of them. So the easiest is to just send it back as WKT and use ST_Geomfromtext to get it in the database.

Leave a Reply

Your email address will not be published. Required fields are marked *