I uploaded a polygon layer in EPSG 25830, called 'parcels'.
I know that the geometries are reprojected and the dataset has two geometry columns:
- 'the_geom' in EPSG 4326
- 'the_geom_webmercator' in EPSG 3857.
To reproject the layer I added it to a map, which only has that layer. I used CARTO ‘Builder’. In the SQL option of the layer, I executed the following sentence, according to the documentation:
SELECT
ST_Transform(the_geom_webmercator, 25830) as the_geom_webmercator,
cartodb_id,
the_geom,
area
FROM
parcels
The SQL sentence runs, but the polygons disappear out of the map, despite I pressed the button ‘Center map on layer’, and played with the zoom. The data of the table continues appearing.
I also changed the base layer to a ‘color’ type, and also a personalized WMS. The layer polygons do not appear. When I reset the layer data to SELECT * FROM parcels
the polygons appears over the personalized WMS basemap.
I also wanted to know how to request personalized WMS base maps in EPSG 25830, or any other SRC, if it is possible?