Direction to a fixed location B (the bearing at the starting location A of the shortest route) corresponds to the direction on the map from A to B:
Littrowthe only conformal retroazimuthal projection
Hammer retroazimuthalalso preserves distance from the central point
Craig retroazimuthal aka Mecca or Qiblaalso has vertical meridians
Side-scan uses a sonar device that emits conical or fan-shaped pulses down toward the seafloor across a wide angle perpendicular to the path of the sensor through the water, which may be towed from a surface vessel or submarine, or mounted on the ship's hull. The intensity of the acoustic reflections from the seafloor of this fan-shaped beam is recorded in a series of cross-track slices. When stitched together along the direction of motion, these slices form an image of the sea bottom within the swath (coverage width) of the beam. The sound frequencies used in side-scan sonar usually range from 100 to 500 kHz; higher frequencies yield better resolution but less range.
A variety of archaeological sciences are used in underwater archaeology. Dendrochronology is an important technique especially for dating the timbers of wooden ships. It may also provide additional information, including the area where the timber was harvested (i.e. likely to be where the ship was built) and whether or not there are later repairs or reuse of salvaged materials. Because plant and animal material can be preserved underwater, archaeobotany and archaeozoology have roles in underwater archaeology. For example, for submerged terrestrial sites or inland water, identification of pollen samples from sedimentary or silt layers can provide information on the plants growing on surrounding land and hence on the nature of the landscape. Information about metal artifacts can be obtained through X-ray of concretions. Geology can provide insight into how the site evolved, including changes in sea-level, erosion by rivers and deposition by rivers or in the sea.
Jason started his television career in 1964 playing the part of Bert Bradshaw in Crossroads. In 1967, he played spoof super-hero Captain Fantastic, among other roles, in the children's comedy series Do Not Adjust Your Set (Rediffusion London/ITV) with Eric Idle, Terry Jones, Denise Coffey and Michael Palin. Humphrey Barclay, who recruited Jason to appear in Do Not Adjust Your Set (partly to offset the rather intellectual style of Idle, Jones and Palin), admired his sense of timing. The programme ended in 1969, and the character then appeared for a time in the Thames Television children's programme Magpie.
Jason was going to be cast in the role of Lance Corporal Jones in the Jimmy Perry and David Croft BBC comedy Dad's Army. Croft had been very impressed with the actor and knew that he had the ability to play a man much older than his real age. However, Bill Cotton over-ruled him, casting Clive Dunn. Jason appeared in the BBC comedy series Hugh and I, which starred Hugh Lloyd and Terry Scott as two friends who lived together in south London. He appeared in Randall and Hopkirk ("That's How Murder Snowballs", 1969) as Abel, a framed performer in a major London theatre.
In the 1970s, he also acted in radio comedies, including the weekly topical satire Week Ending (in which he regularly played such figures as then UK Foreign Secretary Dr David Owen) and The Hitchhiker's Guide to the Galaxy (as the "B Ark Captain" in the sixth episode, in an in-joking reference to his Week Ending role as Owen). Jason also appeared in The Next Programme Follows Almost Immediately and made appearances on panel games such as The Impressionists as well as his own series, The Jason Explanation. In the early 1970s, he appeared in Mostly Monkhouse.
Jason appeared in variety shows in support of stars such as Dick Emery and his performances caught the attention of Ronnie Barker. Jason was recruited to appear in Hark at Barker (LWT, 1969), starring Barker as Lord Rustless, as Dithers, the hundred-year old gardener. There was also a sequel, His Lordship Entertains (1972) for the BBC. Jason played junior employee Granville in the first programme of the comedy anthology Seven of One (1973), called Open All Hours (BBC) and starring Barker as the miserly proprietor of a corner shop.
Four series of Open All Hours were made from 197685. He featured in Barker's Porridge (BBC), a prison-based comedy, as the elderly Blanco in three episodes. Jason also appeared with Barker in various disguises in The Two Ronnies.
Jason starred in London Weekend Television's Lucky Feller (197576), written by Terence Frisby and produced by Humphrey Barclay. About two brothers in South-East London, the series was in many ways a forerunner to Only Fools And Horses, only Jason was in the more dopey 'Rodney' role with Peter Armitage playing the cleverer of the two. The brothers drove around in a comical bubble car, a precursor to the famous Trotters' van; and there was even the joke where, just as he was trying to impress the girl (Cheryl Hall), Jason casually leaned back against the bar, without his knowing that barman had just lifted it behind his back, and fell through. This situation was re-enacted in Only Fools And Horses. He played the lead role in the ATV sitcom A Sharp Intake of Breath (197781). In 1979, he appeared as Buttons in the pantomime Cinderella at Newcastle's Theatre Royal, starring Leah Bell and Bobby Thompson, produced by Michael Grayson and directed by John Blackmore.