Sedimentary Rocks when igneous rocks are exposed to surface and weathering reduces them to particles, these particles are moved by erosional process and deposited in layers into rivers and oceans . 51
Metamorphosed Rocks when sedimentary rocks are pushed to deeper levels of the earth, they transform into metamorphosed rocks due to changes in pressure and temperature . 52
SOIL EROSION when rocks are broken down (weathered) into small fragments, and carried by wind, water, ice and gravity. Energy for this process is solar and gravitational. 53
Hydrologic cycle or the planet’s water cycle, described by the movement of water from the oceans to the atmosphere to the continents and back to the sea . HYDROLOGY The natural science that studies the Waters of the Earth, their occurrence, circulation and distribution, their chemical and physical properties, and their reaction to the living environment including their relation to all living things. 54
THE CULTURAL FACTORS 5055
i. EXISTING LAND U S E Land Use Plans are available in each city and municipality to determine the areas for commercial, institutional, industrial, residential, and open space uses. These were planned according to the most rational use of land in relation to the natural and socio- economic factors, and in accordance with compatibility with adjacent land uses. Each site must conform to the land use plan: a residential subdivision, for example, cannot be developed in a site designated as Industrial. 56
ii. TRAFFIC AND TRANSIT SYST E M S The relationship of traffic pattern to each other and to the site must be studied for adequacy of access and efficiency of circulation within and outside of the site. Efficient traffic and transportation systems will result in successful integration of the different developments in the vicinity. Direction of dominant traffic flow, both vehicular and pedestrian will also help establish points of highest visual impact for the site. Access must also consider pedestrian movement. 57
iii. DENSITY AND ZONING Density refers to the population per unit land area. This data will determine whether existing utilities and land areas will be sufficient to sustain additional future development, which will naturally add to the existing population and bear on the capacity of these utilities. Density is expressed in number of families or dwelling units per hectare. It may also be expressed in Floor Area Ratio (FAR). Density influences the privacy, social contact among people, and freedom of movement of an individual or a group of people. Zoning regulations, laws and codes are present in every city and municipality to regulate the type of development. It divides the city or municipality into land use areas that are designated by building height, building coverage, density of population, and open space. 58
iv. SOCIO-ECONOMIC FACTORS The study of the community and its social and economic structures are done to determine whether there is a need, an interest, or any objections on the project. Any proposed project must be compatible with the economy of the particular community. For example, a high-end boutique is hardly suitable in a lowincome community. The social structure of the community must be taken into consideration to ensure that a proposed development will not result in any displaced families, and any major disruption in their businesses and other activities. 59
v. UTILITIES/SERVICES It is important to determine the existing availability of utilities on site in terms of adequacy and efficiency. This includes: • Sanitary/sewage system • Electric power supply • Water supply • Drainage Most water systems will supply domestic, industrial, and fire stand-by supply from a distribution system. Storm drains collect surface water and conduct it to rivers, creeks, or other bodies of water. 60
THE AESTHETIC FACTORS 5661
NATURAL FEATURES When sites are characterized by outstanding natural features of earth, rock, water or plant material. These may be incorporated in the site development as natural assets of the land. 62
SPATIAL PATTERNS: Spatial pattern is defined as the way an open space of a given site is configured according to an arrangement of elements that evoke activity or flow, both physically or visually. 63
VISUAL R E S O U RC E S 1. View is a scene observed from a vantage point. A view can be a theme that may suggest and give added meaning to buildings. The full view is not always the best view. 64
VISUAL R E S O U RC E S 2. Vista is a confined view, usually directed toward a terminal or dominant feature. It has three components: a viewing station, a view, and a foreground. A view is usually better if enframed or seen through an appropriate screen. 65
Chapter 3 Contour And Slope Analysis 66
What Is Topography? Topography is the physical and natural features of the land A topographic map shows natural features (such as elevation) and man made features (such as schools) 67
Contour Lines The squiggly lines on a topographic map are called contour lines Contour lines are lines that represent a certain height or elevation All points on a contour lines are the same elevation 68
Contour LinesAnd Elevation ⚫ Imagine a picture of a mountain and then imagine there were lines drawn around it every 20 feet ⚫ What would the mountain with the lines look like if you stood on the side of it? ⚫ What would the mountain with the lines look like if you were looking down on it from an airplane? 69
Contour LinesAnd Elevation The closer the contour lines are to each other, the steeper the slope is! 70
Mistakes in the contour line Contour lines of different heights can never cross each other. Crossing contour lines would mean that the intersection point has two different elevations, which is impossible. 71
Mistakes in the contour line A contour line is continuous; there can never be an isolated piece of contour line somewhere on the map, as shown in Figure below. 72
OtherTopographic Terms Map scale – compares distances on the map with distances on earth. Legend – explains symbols used on the map. 73
OtherTopographic Terms Index contours – contour lines that are labeled to help you find the contour interval. Relief – the difference in elevation between the highest and lowest points in a region 74
A contour interval is the difference in elevation between two contour lines that are side by side. Remember that a contour interval is not the distance between the two lines – to get the distance you need to use the map scale. OtherTopographic Terms 75
To be complete and really useful, a map must have a defined scale. The scale is the ratio of the distance between two points on a map and their real distance on the field. A scale of 1 in 5000 (1:5000) means that 1 cm measured on the map corresponds to 5000 cm (or converted into metres, 50 m) on the field. QUESTION What is the real distance between points A and B on the field when these two points are 3.5 cm apart on a map whose scale is 1 to 2 500? Scale of map 76
ANSWER The scale is 1:2 500, which means that 1 cm on the map represents 2 500 cm in reality. Thus, 3.5 cm between A and B on the map corresponds to 3.5 x 2 500 cm = 8 750 cm or 87.5 m on the field. Scale of map 77
AnswerThe Following… Circle the map scale Is there legend? Circle at least one index contour What is the contour interval? 78
Mountains Mountains are represented by a series of circles This is a top down view 79
Depressions A depression is an area or land that is lower than the surrounding area. O n a topographic map, depressions are marked with small inward line (hachured lines). such as the inside of a dead volcano, is represented by Hachure lines. Ha chure lines are regular contour lines with small segments sticking out from it. The first hachure line is at the same elevation as the contour line before it. 80
Streams The direction a streams is flowing is shown on a topographic map by the way a contour line crosses the stream. Streams are found in areas of lowelevation Streams are shown as a blue line on maps. When contour lines cross a stream it lookslike an upside down V. The point in the V points upstream. It opens in the direction the water is flowing. 81
AnswerThe Following…. What letter represents the stream? What type of elevation is here? Which way is the water moving: to the right or to the left? 82
Topographic Symbols Mappers, also called cartographers use symbols to represent certain things on a topographic map For example, the color green represents an area with lots of trees or vegetation 83
Topographic Symbols Red is used to show a road, highway or interstate 84
Topographic Symbols Buildings are usually shown as little black squares 85
Landforms On aTopographic Map The map below shows a simple topographic map including a spur, cliff, valley and plateau. FigureA 86
ReadingContour Lines o By reading the contour lines an understanding of the shape of the land is obtained. Land features are identified from the contour lines. o You will need: 1. A topographic map. o Procedure : Use the contour lines to identify land features Step 1 Look at the contour lines on figure A. You will see that sometimes the lines are close together and sometimes the lines are further apart. Identify two areas where this is the case. 87
Step 2 Using your hand, create the shape of a hill. For every 50 metres increase of the hill slope, move your hand higher and at each step visualise that this is the next contour line on a map. Try this for some other landforms that you are familiar with, such as a valley or a beach cliff. Did you recognise that if the contours are close together then the shape of the land is steep, and if the contours are further apart then the land is flatter? Step 3 Landforms have distinctive shapes with contours, which a geographer recognises on a topographic map as a particular land feature. Use figure A as a guide to understanding the shapes on maps as land features. Create your own hand models of the shape of each land features. 88
Cross Section Cross sections are useful for visualising the features on a topographic map. The following is provide to remind you how to draw a cross section. 1. Line up the edge of a piece of plain paper along the line marked AB 2. Make a small vertical mark on your paper where each contour line meets it. Also draw small mark below A and B and label them A and B . Near each vertical mark, write the height of the contour. Use the contour interval to help you work this out. 89
3. Line up your mark-up piece of paper against a graph you have drawn. Your graph should be exactly the same width as the length of the line between A and B . 4. Line up the A with the vertical axis of your graph. For each vertical mark on your piece of paper make a corresponding dot on your graph (to record the height of the contour above sea level). 90
5. Join the dots to create your cross-section. 6. Give your cross section a title. If you wish, you could shade of your complete crosssection is clearer. 91
SlopeAndTopography Slope and topography describe the shape and relief of land. Topography is a measurement of elevation and relief of the Land. Topography is measured with contours that connect points representing the same elevation. Slope is the difference in elevation from one point to another divided by the lateral distance between those points. 92
Slope A slope is the rise or fall of the land surface. It is important for the farmer or irrigator to identify the slopes on the land. A slope is easy to recognize in a hilly area. Start climbing from the foot of a hill toward the top, this is called a rising slope (see Fig. A, black arrow). Go downhill, this is a falling slope (see Fig. A, white arrow). Fig. A : A rising and a Fallingslope Flat areas are never strictly horizontal; there are gentle slopes in a seemingly flat area, but they are often hardly noticeable to the naked eye. An accurate survey of the land is necessary to identify these so called "flat slopes". 93
SlopeAnalysis the process of areas for placing Slope analysis is determining the best buildings, roads, etc. Slope analysis is used to measure the suitability of the gradient of the terrain for each type of development. Slope is a measure of the steepness of a surface and may be expressed in either degrees or percent of slope. In this example, the red cells show steep areas and the green cells show flat areas. 94
SlopeAnalysis Typical questions: 1. Contour interval, pattern of landform 2. Natural drainage pattern 3. Unique features 4. Slope analysis and percent slope 5. Site dangers: Land slide potential, skin hole 95
Reduce construction costs Minimize risks from natural hazards such as flooding and landslides Minimize the impacts of proposed developments on natural resources such as soils, vegetation and water systems. Create a model of the land surface (digital elevation model) or three dimensional physical models. WhyAre Slope and Topography Important? 96
TerraceGrading • Terracing is important in hillside development (sloping terrain). • Terraces may be graded in three ways (cut, fill or cut and fill). • Grading can be done for roads and buildings. • The key point to the process of grading roads and buildings is to direct and restrict storm water runoff. • There is a direct proportional relationship between change in elevation and horizontal distance between contour lines (e.g. 1.0 ft change in elevation at 3% slope requires a distance of 33.3 ft while 0.5 ft change requires half of that distance – 16.7 ft). 97
Guideline Regarding Topography Preservation a) Garis Panduan Perancangan Pembangunan Di Kawasan Bukit dan Tanah Tinggi yang dikeluarkan oleh Jabatan Perancangan Bandar dan Desa Semenanjung Malaysia. (2009) These guidelines are provided to plan and control development activities in hilly areas, highlands, slopes and hilltops and areas around it. The function of these guidelines are: ⚫ used by state and local authorities (local authorities) in considering the application for planning permission and development proposal reports (LCP). ⚫ used by implementing agencies, developers and the public for guidance in selecting, planning and developing sites within the region hilly, highlands, slopes and peaks and surrounding areas. 98
Definition Of Hilly Areas • Hilly Areas :Height of 150m –300m [also known as catchment area and Environment Sensitive Area (KSAS)]. • Highland Areas: Level more than 300m and less than 1000m from sea level. 99
AspectOf Height * Datum is a surface level where all measurements will be referred • Level of height is categorized into 4: • Low land (<150m) • Hilly area (150-300m) • Highland (300 – 1000m) • Mountain (>1000m) • For certain towns which are located at natural plateau area, height level is based on each town datum 100