To orient at e yourself is t o est ablish your posit ion• “oriens” (Lat in) - rising of t he sun or east• f ind dist inct ive landmarks andcorrelat e phot ograph wit h act ual landscape• orientation in terms of direction -cardinal points of the compass• in South Africa shadows fall to the southOrientation
What is a map?A map is a generalised and reducedrepresent at ion of (a port ion of ) t hecurved surface of t he eart h on a flatsurfaceOr t hophot o Map• a combinat ion of an aerialphot ograph and a map• a rect if ied image and t rue t o scaleOrthophoto MapsHow does t he ort hophot o map dif f er f romt he vert ical aerial phot ograph?
• A let t er or symbol indicat ing a part icular f eat ureWhat is a convent ional sign?Conventional Signs (1)Point Line Area
Conventional Signs (2)Making it easier:Dist inguish bet ween t wo t ypes of landscape:• t he nat ural / physical landscape• t he const ruct ed / human landscape• Five colours- Brown- Blue- Green- Black- Red
1:50 000• This is a mat hemat ical wayof expressing t he scale• Only numbers are used and it ref ers t ot he same unit of measurementNumerator• The numerat or is always 1& represent s t he mapRatio ScaleDenominator• The denominat or is always bigger& represent s t he ground
map dist ance in cm ground dist ance equivalent i.e. 50 000100 000E.g. 3,7 cm on t het opographic map3,7 x 50 000100 000= 1,85 km• To convert cm t o km you must divide by 100 000 (1km = 100000 cm)• Conver t ing dist ance on t he 1:50 000t opographic map:x1:10 000ort hophot o map10 000Converting cm to km3,7 x 10 000100 000= 0,37km or 370mE.g. 3,7 cm on t heort hophot o map