I imported a CSV file with coordinates into a PostGIS table. This table contains a column "latitude" and a column "longitude". The coordinates in these columns are in EPSG:4326. What is the best way to convert these coordinates to EPSG:28992? Is it possible to do that directly, or should I convert these coordinates to geometry first?
Once you have loaded the CSV into postgresql, you can use postgis to build the geometry temporarily, transform it, and extract the lat/lon like this:
select schnum --school #'s from my schools table , lon --original 4326 , lat --original 4326 , ST_X(ST_Transform(st_setsrid(st_makepoint(lon, lat), 4326), 102654)) as new_lon , ST_y(ST_Transform(st_setsrid(st_makepoint(lon, lat), 4326), 102654)) as new_lat from csv
You can then export to a new CSV.