Complete flight plan example

An area $100km$ long in the north$-$south direction and $50km$ in the cast$-$west direction is to be photographed with a lens having $21cm$ local length for the purpose of compiling a topographic map $($that means photographs to cover an area of $100kmx50km.$ The size of the photograph is $18cm18cm.$ The average scale is to be $1$:$20,000$ effective at an average elevation of $500m$ above datum. Overlap is to be at least $60\%$ and sidelap is to be at least $20\%.$ The ground speed of the aircraft will be maintained at $300km$ per hour. Determine $($i$)$ flight height $($altitude of the aircraft$),($ii$)$ number of flights $(N_2)$ required, $($iii$)$ number of photographs in each strip $(N_1),($iv$)$ exposures intervals, and $($v$)$ total number of photographs required.