The examples at https://schema.org/longitude and https://schema.org/longitude and https://schema.org/GeoCoordinates and https://schema.org/geo in Microdata, RDFa, JSON-LD for the Empire State Building (at 40.748433 N, 73.985656 W) should show a negative value (-73.98) instead of a positive value (73.98) because longitude is conventionally measured with positive values to the east of the prime / Greenwich meridian and with negative values to the west of the prime / Greenwich meridian.
Please correct the errors in the examples so that every occurrence of 73.98 becomes -73.98.