Cartographic skills

6.5.2 Case study: Sino-Singapore Tianjin eco-city

7.2 Graphical skills

Cartographic skills

  1. Scale

    1. Every map has a scale to make it a manageable size
    2. The scale is written in the form 1:x denoting that 1 unit of length on the map represents x units of real-world length
    3. Typical scales are 1:50000, whereby 1 cm represents 500 m or 2 cm represents 1 km, and 1:25000, whereby 1 cm represents 250 m or 4 cm represents 1 km

  2. Positioning

    1. Grid references

      1. Positions on Ordnance survey maps are represented using grid references
      2. The British Isles is split into 100 km by 100 km squares with a unique 2-letter identifier
      3. Each square has its sides dilimited into 100 divisions, resulting in 10,000 squares of size 1km by 1km, each with its own 4-figure grid reference, read by taking the horizontal coordinate, from the bottom-left, then the vertical coordinate
      4. Each 1km2 square can be further delineated into 100 squares of size 100 m by 100 m with a 6-figure grid reference wherein the third & sixth number is the delineation of the respective side
      5. The grid reference of each square is the delineation at its bottom-left corner

    2. Latitude & longitude

      1. Latitude specifies the north-south position of a point on Earth’s surface, and is represented by an angle between 0° at the equator to 90° at the poles followed by N or S depending on whether the point is north or south of the equator
      2. Longitude specifies the east-west position of a point on Earth’s surface, and is represented by an angle between -180 to 180°, with the positive direction denoting east and the origin going through the Royal Observatory in Greenwich, England

    3. Compass

      1. Compass directions specify the relative direction between two points relative to the four cardinal directions: north N, east E, south S and west W, going clockwise
      2. Directions can be further specificised by taking intermediate directions halfway between the cardinal points: north-east NE, south-east SE, south-west SW and north-west NW, going clockwise from north

  3. Relief

    1. On OS maps, relief is emulated using contour lines that delimits the areas that are higher and lower than a particular height above sea level
    2. Contour lines are typically drawn every 5 metres, though it can be 10 in hilly or mountainous areas, and are marked with the height number, oriented so that the top of the text goes uphill
    3. The closer together the contour lines in an area, the steeper the gradient in that area

    4. Major relief features can be identified by their contours and cross-section:

      1. A ridge is a chain of mountains or hills that form a continuous elevated crest for a long distance
      2. A valley is a depression that is longer than it is wide, often with a river running through it; it is characterised by a V-shaped or U-shaped cross-section and a V-shaped or U-shaped contour shape wherein the centre is lower than the sides
      3. An escarpment is a steep slope or long cliff that separates two relatively level areas of differing elevations; it is characterised by a vertical cross-section surrounded by more horizontal land and a series of very close contour lines surrounded by lines that are farther apart
      4. A plateau is an area of highland, typically relatively flat, that is significantly above the surrounding land, often with steep slopes; a dissected plateau is one that has been severely eroded, possibly by fluvial or glacial action, so that the relief is sharp
      5. A convex slope is a slope that is steeper at the bottom than at the top; it is characterised by contour lines that are closer together at the bottom than at the top
      6. A concave slope is a slope that is steeper at the top than at the bottom; it is characterised by contour lines that are closer together at the top than at the bottom

  4. Drainage

    1. A drainage basin is an area of land where surface water, such as from rain, converges to a single exit where the waters join another water body, such as a river or the sea; drainage basins are separated by drainage divides
    2. The drainage density of a drainage basin is the total length of streams & rivers in it divided by its area

    3. The drainage system of a drainage basin is the pattern formed by its streams & rivers, and typically fall into one of several drainage patterns:

      1. Dendritic: Dendritic drainage pattern diagram The most common pattern, there are many contributing streams that join into tributaries of the main river, following the slope of the terrain, which forms a V-shaped valley, so the rock is impervious and non-porous
      2. Parallel: Parallel drainage pattern diagram A steep slope results in swift, straight streams flowing in the same direction with few tributaries
      3. Trellis: Trellis drainage pattern diagram Tributaries flow down valleys in synclines, joining at approximate right angles, resulting in a trellis-like appearance; commonly develops in folded mountains, such as the Appalachian mountains
      4. Rectangular: Rectangular drainage pattern diagram Developing in regions that have undergone faulting, creating fractures, called joints, that erode, allowing rivers to preferentially flow through them, resulting in straight tributaries that bend and join at right angles
      5. Radial: Radial drainage pattern diagram Tributaries radiate outwards from a central high point; commonly develops on volcanoes, domes and laccoliths
      6. Centripetal: Centripetal drainage pattern diagram Tributaries converge into a central depression, which forms a lake in wetter periods that evaporates in drier periods

  5. Valley features

    1. Valleys are initially formed by the erosion of a river to produce a V-shaped valley
    2. A U-shaped valley, or glacier trough, is formed when a glacier travels down a valley, transforming the valley shape into a U by the processes by plucking & abrasion
    3. A dry valley is a valley that does not sustain surface water flow because the rock is too permeable
    4. An incised meander forms when the river’s base level falls, which can be due to tectonic uplift or a fall in sea level (this is known as rejuvenation of the river), causing the river to vertically erode immensely and leaving the meander pattern in a deep valley; there are two types of incised meander: entrenched, whereby vertical erosion is rapid, resulting in a more symmetrical valley, and ingrown, whereby vertical erosion is slower, allowing the river to laterally erode more, resulting in a more asymmetrical valley

  6. Coastline features

    1. Headlands & bays

      1. A headland is a high area of land, typically with a sheer drop, that extends into a body of water; a large headland is often called a cape
      2. A bay is a body of water connected to a sea or lake that is enclosed by the shoreline, which often block waves and winds, making the waters calmer, allowing fishing, which was significant in the development of settlements around sea trade
      3. Headlands & bays are often found on the same coastline, formed by the coastal erosion of bands of rock of alternating resistance running perpendicular to the coast: soft rock erodes more, forming bays, and hard rock leaves headlands
      4. Bays can also be by from continental drift

    2. Cliffed coast

      1. A cliff is a vertical, or near-vertical, rock exposure
      2. They are formed when the coastal erosion at the cliff-foot forms a wave-cut notch, leaving an overhang that eventually collapses under its own weight to form a scree, and causing the coastline to recede, leaving a wave-cut platform
      3. Erosion at a weak spot on the side of a headland, such as a joint or fault, can produce a cave, which can break through to leave an arch, which can collapse to leave a stack, which can be eroded to leave a stump

    3. Flat coast

      1. A flat coast is where the land descends gradually into the sea, which deposits sediment to form a beach that consists of loose particles mainly derived from rock, such as sand, but also from organisms, such as mollusc shells
      2. When the prevailing wind does not match the gradient of the beach, the constant swash & backwash results in an overall lateral movement of sediment with a zigzag pattern in a process called longshore drift
      3. A spit develops when longshore drift deposits past the end of the beach to form new land until the water pressure becomes too much for deposition; wave refraction at the end of the spit can cause the shape to curve into a hook shape, called a recurved spit
      4. The water behind a spit is often sheltered from the wind & waves, so can develop into a salt marsh, an ecosystem dominated by a dense covering salt-tolerant plants, such as herbs, and is regularly flooded by tides
      5. A bar is a spit that grows across a bay, trapping a lake or lagoon behind it

  7. Settlements

    1. A settlement is a community in which people live
    2. A dispersed settlement is a rural settlement that typically consists of farms scattered throughout the area
    3. A nucleated settlement clusters around a focal point: traditionally a church close to the village green
    4. A linear settlement forms a long line, typically following a transport route, such as a road or river, though some form around physical restrictions, such as coastlines; they have a long, narrow shape and may have no centre, and those along a route probably grew after it, originating around a station or feature

  8. Urban morphology

    1. Urban morphology is the study of human settlements, their formation and transformation
    2. The central business district, located in the centre of the city, is easily accessible and the main shopping & service area, characterised by high-rise, high-density buildings
    3. The inner city, located next to the CBD, was build to house factory workers who worked in the factories, and is characterised by mainly terraced houses in a grid-like pattern
    4. The suburbs, located on the outskirts of the city, has higher-quality housing for people who can afford to commute into the city
    5. The rural-urban fringe is the edge of a town or city where town and country meet and where urban & rural land uses mix and often clash
    6. A retail park is an unenclosed shopping centre, typically with three or more big box retailers and various smaller retailers with a shared parking area, found on the fringes of most large towns or cities, offering a highly-accessible alternative to busy city centres for households with cars
    7. A business park is an area where many office buildings are grouped together for commercial, consumer-oriented work; it is often in suburban locations near motorways or main roads
    8. An industrial estate is an area zoned on industrial development and is a more heavyweight version of a business park; it is often located outside the main residential areas with good transport links, such as road and rail, especially where many coincide
    9. A gridiron is a city plan in which streets run perpendicular to each other, forming a grid pattern
    10. A terrace is row of identical houses that share side walls, and is often associated with the working class, but have increasingly been part of the gentrification of inner cities
    11. A cul-de-sac is a street with only one opening, and is often used to limit through-traffic, some allowing non-automotive traffic to pass through on footpaths in a process called filtered permeability

  9. Human activity

    1. A honeypot site is one that attracts a large number of tourists, which pressures on the environment & people
    2. A national park is land, often natural, owned by a sovereign state to conserve for posterity and natural pride
    3. A national trust is an organisation dedicated to preserving the cultural heritage of a particular geographical region, often preserving areas of historical significance or natural beauty; it is modelled after the National Trust for Places of Historic Interest or Natural Beauty, a charitable organisation operating in England, Wales and Northern Ireland, which owns many heritage properties, many of which are open to the public free of charge