Category URL
_null http://atn.ioos.us/erddap/categorize/standard_name/_null/index.xhtml?page=1&itemsPerPage=1000
latitude http://atn.ioos.us/erddap/categorize/standard_name/latitude/index.xhtml?page=1&itemsPerPage=1000
longitude http://atn.ioos.us/erddap/categorize/standard_name/longitude/index.xhtml?page=1&itemsPerPage=1000
time http://atn.ioos.us/erddap/categorize/standard_name/time/index.xhtml?page=1&itemsPerPage=1000