question: public int elevationAt ( float lat , float lon ) { if ( frame_is_valid == true ) { if ( lat >= dsi . sw_lat && lat <= dsi . ne_lat && lon >= dsi . sw_lon && lon <= dsi . ne_lon ) { int lat_index = Math . round ( ( lat - dsi . sw_lat ) * 36000 / uhl . lat_post_interval ) ; int lon_index = Math . round ( ( lon - dsi . sw_lon ) * 36000 / uhl . lon_post_interval ) ; if ( elevations [ lon_index ] == null ) readDataRecord ( lon_index ) ; return ( int ) elevations [ lon_index ] [ lat_index ] ; } } return - 32767 ; }
target:  The elevation at the closest SW post to the given lat/lon. This is just a go-to-the-closest-post solution.