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# Gis Tutorial Purnawan

## on Apr 01, 2009

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## Gis Tutorial PurnawanPresentation Transcript

• 3. Raster and Vector GIS measurement
• Question 3a Raster Gis Distance measurement C = [3x300]²+[7x100]² Euclidian Manhattan M = 3 X 300 + 7 X 100 = 1600 m C Source : Google Maps = 1140.17 m
• 3b. Vector GIS Area measurement A B F C D E 600 m Source : Google Maps
• Formulation
• Area of rectangular
• Area = Length x Width
• Area of triangular
• Area = ½ Length x Width
What total Area of Caird Park ?
• Area A and B
• Area A = 550 x 375  206250 m²
• Area B = 1100 x 300  330000 m²
• Area C, D and E
• Area C = ½ 550 x 600  175000 m²
• Area D = ½ 300 x 50  7500 m²
• Area E = ½ 250 x 50  6250 m²
• Area F
• Area F = ½ 1050 x 250  131250 m²
• Area A = 206250 m²
• Area B = 330000 m²
• Area C = 175000 m²
• Area D = 7500 m²
• Area E = 6250 m²
• Area F = 131250 m²
• Total = 846250 m² Approx True ????
• So what is wrong ? Area C = 165000 m²
• 4. Six Key elements of map design ?
• Frame Of Reference
• Projection Used
• Feature to be Mapped
• Level Of generalization
• Annotation
• Symbolism
• Question ?
• How far does the car move ?
• Where does it move ?
1 5 7 N m
• Question : The Frame reference Heywood, et.al, An Introduction to GIS, p255
• What are the 6 key maps design elements Frame Reference
• A map is scale model of the real world so it needs some form of spatial reference so the user can fix its location in the real world . Mechanism that can be used to provide this:
• A grid with lines (representing latitude longitude) or planar (x.y) co-ordinates
• A north arrow in conjunction with a scale bar
• An inset map
• What are the 6 key maps design elements Projection Used
• Map projections can radically affect measurements such as area or distance. Small scale maps of larger areas are more affected by the projection method. For maps of large areas, decision need to be made regarding what is most important (i.e. area, distance, directions, lines of true scale etc)
Heywood, et.al, An Introduction to GIS, p47
• Question Heywood, et.al, An Introduction to GIS, p255 Projection
• What are the 6 key maps design elements Features to be mapped
• Maps are by definition a communication device for spatial information, so it is important that the map shows only what is necessary to get that intended message . It should contain no distractions