Updatesector

updatesector <x> <y> <gamevar>
updatesectorz <x> <y> <z> <gamevar>

Returns sector id of the sector containing the point (<x>,<y>) or (<x>,<y>,<z>) into <gamevar>. If it is not a valid sector (like outside the map, inside a column, or below the floor), it returns -1. You should verify that the value return is not equal to -1 before manipulating the sector or you could have problems.