LANDFORMS GROUP 3 A. Kavivya M. Kuria K. Kipng etich K. Kilonzo N. Mark O. Zindzibel K. Jebichi
Meaning: Physical design element used to meet a landscape architect s objective in creating and managing outdoor spaces Synonym of Topography Impacts design elements directly as a base plan before design
SIGNIFICANCES
AESTHETIC CHARACTER FLAT AREAS Appears open and expansive looking on to the horizon Sense of visual continuity and unity Sky and sun form a dominant element i.e strong ceiling and light source E.g. beach fronts
HILLY AREAS Feeling of separation and isolation When in a valley, mountain slopes form dominant element Sky reduced to a smaller area
Perceptual rhythm created by sizes between ridges
SPATIAL SENSATION AND DEFINITION SENSATION Affect a persons sensation of an outdoor space The greater the slope the higher the sensation : smooth flowing landforms- relaxation mood bold rugged landforms- excitement and aggressiveness
DEFINITION
VIEWS ESTABLISH DRAMMATIC VIEWS CREATE SEQUENTIAL VIEWS PROGREESIVE REALIZATION VIEWS SCREENING UNFAVOURABLE VIEWS (PRIVACY)
SCREENING FOCAL POINT VIEWS
DRAINAGE LANDFORMS AFFECTS: AMOUNT OF RUNOFF DIRECTION OF FLOW RATE OF FLOW
MICROCLIMATE AFFECTS SUN EXPOSURE WIND EXPOSURE PRECIPITATION ACCUMULATION
SLOPE ORIENTATION ON SUN EXPOSURE (TEMERATE ZONE)
SLOPE ORIENTATION ON SUN EXPOSURE (TEMPERATE ZONE)
LANDFORM TYPES 1. Level landform 2. Convex landform 3. Concave landform 4. Ridge landform 5. Valley landform Categorized in terms of: scale Character steepness geological origin form.
1.Level Landforms Defined as any land area visually parallel to the plane of the horizon. Initially there is no level lend. level landforms is used to mean any landform that appears level even if it is slightly sloped or gently rolling.
Characteristics Of Level Landforms
Where does it work best? MASSIVE SPREAD BUILDINGS PARKING AREAS RECREATIONAL FACILITIES
2. Convex Landforms Dynamic Aggressive Exciting Landform Implying Power And Strength Hilltops
Used as focal points Important structures are often placed on top of a convex landforms to take advantage of this feeling of being looked up to Churches Government buildings
Used To Provide Outward Oriented Views
3. Ridge Landform It is a stretched out version of a convex form i.e., it is linear in its overall mass
Ridge line and terminal points of a ridge provide views and an outward orientation into the surrounding landscape
Buildings, roads, and parking are sited in linear manner on top of ridges
4. Concave landform Is defined as bowl like depression in the landscape. It is negative solid and positive space (void) that completes a landform composition when placed next to a convex form
Characteristics of concave landforms 1.Feeling of isolation
2.Amphitheatres or other similar structures involving viewing audiences are logically located on sloped ground or in natural concave landforms
5. Valley Landform Like a concave landform, valley is a low area in the landscape that functions as a positive space or room where activities may occur. Moreover valley is like a ridge in that it is linear and directional.
Characteristics of a valley landform Valley floor is fertile and can be used for agriculture, open space and recreation. Roads should be placed on the edge of the valley.
USES OF LANDFORMS There are a number of functional and aesthetic uses of landform in the outdoor environment In all cases, the use of landform depends on the designer's skill and imagination: 1. Spatial Definition 2. Control Views 3. Influence Movement 4. Affect Microclimate 5. Aesthetic Uses
1. Spatial Definition Landform may be used to create and define exterior space by several different means. Space may be created by excavating into the existing base plane, filling (adding) earth and building up from the existing base plane, complementing existing convex landforms with added high points, or changing elevation to establish terraces or level variations. Most of these techniques are effective means for creating concave and valley landforms. When defining exterior spaces with landform, three variables are critical in influencing our perception of space: 1) the floor area of the space 2) the steepness of the enclosing slopes 3) the horizon/ silhouette line.
1. Floor area of the space: This is the bottom or base plane of the space and generally represents the "usable area. It may appear as a distinct flat area or be more subtly defined, blending into and appearing to be part of the side slopes. Typically, the larger the floor area of a space, the larger the space is perceived to be. 2. Slope Slope assumes the function of the vertical plane by acting as walls of an exterior space. The slope steepness has a bearing upon spatial definition: the steeper the slope, the more pronounced the delineation of space.
3. The Horizon/ Silhouette Line It represents the edge between the perceived top of the landform and the sky. We read this line as being the upper edge of the slope regardless of its size. Its position with respect to height and distance from the position of the viewer, affects views out of the space and the perceived spatial limits. The area seen within these limits is sometimes referred to as a "view shed." At the regional scale, the horizon/ silhouette line may be defined by the ridge of the distant hills or mountains far away. This very large space may then be subdivided into smaller spaces in the more immediate foreground. Figure 1.70 sh0n.s that the horizon/ silhouette line (and the related perception of space) changes as one moves through and about a space. The space may seem to expand or contract depending on one's position in relation to the horizon/ silhouette line.
The normal field of vision spans a vertical angle of about 60 degrees with 40 degrees above the eye-level plane and 20 degrees below the eye-level plane. The feeling of full enclosure is gained when the combination of the three variables fills and/ or extends beyond a 45-degree cone of vision. And a minimum sense of enclosure occurs when the variables occupy an 18-degree field of vision Using these 3 variables, the landscape architect can create an almost limitless variety of spatial experiences from an intimate space to a monumental one
example
2. Control of views By filling the vertical plane, landforms can: a) direct views to specific points in the landscape b) influence what and how much is seen at any given point (view shed) c) create sequential viewing or progressive realization d) completely block views from objectionable scenes. As with spatial orientation, views are directed along lines of least resistance toward open spaces.
a) Directing views Landform may be used to "show off" or exhibit a particular object or scene as well; Objects placed on a high point of ground or summit are easily seen from potentially great distances. Likewise, objects or areas located on the side slopes of a valley or ridge are also readily seen from lower areas in the valley or slopes on the opposite facing side of the valley. The steeper the slopes, the more they become like vertical walls and the more they directly stop and capture the line of sight. Another similar use of landform is to create a series of vantage points from which to view an object or space. Each vantage point can be so located as to provide a new or different perspective of the object being viewed.
b) Shedding Views Landforms may be built up in the form of earth mounds or berms to screen out displeasing objects or scenes. This approach is common along roads, parking areas, and commercial establishments to block undesirable views of cars, service areas, and storage.
3. Influence Movement Landform may be used in the exterior environment to influence the direction, speed, and rhythm of both pedestrian and vehicular movement. Typically circulation follows paths of least resistance, which in terms of topography are usually relatively level flat areas devoid of any obstacles. Here, minimum energy expenditure is necessary to walk in an uninterrupted manner. Thus an ideal location for roads and paths is on the level landform, along the valley floor, or on top of the ridge, as suggested previously.
If movement is required up or down a steeper area of ground than this, it should occur askew to the contours, not perpendicular to them, to minimize path steepness. When there is a need to cross a Ridge like landform, it is easiest to do so by moving through a "gap" or "saddle" if one is present. Another application of these principles is to affect the rate of movement in a design; If the intent in a portion of a design is to permit people to move quickly through an area, a level ground area should be used. If, on the other hand, the objective is to make the user walk slower through a space, sloped surfaces or changes in elevation between a series of levels should be applied. And where it is intended to have people stop their movement altogether, a level ground area should again be utilized. Landform in the form of slopes and earth mounds can be used as obstacles or barriers, forcing movement around them and through the valley like spaces.
c) Sequential viewing or progressive realization: A related use of landform is to establish spatial sequences that alternately reveal and hide views of objects or scenes. This concept is referred to as sequential viewing or progressive realization. It creates anticipation and makes the viewer want to see more of the object Example the base may be hidden then revealed as the viewer approaches the object, or sequentially hidden and revealed as the object is approached
4. Affect microclimate Landform can be used in the landscape to modify microclimate. 1. In terms of sun, south-facing sloped surfaces can be used or artificially created to establish areas that receive direct winter sun with resulting warmer surface and air temperatures 2. In terms of wind, landforms such as convex forms, ridges, or mounds can be used to block cold winds from a site during the winter season. To do this, the earth should be built up on the sides of the site or use area facing the winter winds.
5. Aesthetic Uses
SUMMARY Landform is a very significant element in the exterior environment. It influences the aesthetic character of outdoor spaces, spatial perception, views, drainage, microclimate, and land use organization. Because of its importance and the fact that all other elements in the landscape rest on the ground plane, it is one of the first considerations in the evolution of a design. How landscape architects shape landform affects the appearance and function of buildings, plant material, pavement, water, and walls.
EXPRESSION OF LAND FORMS. Contours Spot elevations Hachures Value and colour Model Comp graphics Ratio method percentage
CONTOURS Most common way of expressing landforms. It connects all points that are equal vertical distances above or below a horizontal reference plane. The contour interval remains the same through the contours and is only affected by the scale of the plan, steepness of the site and complexity of the landform. Grading are the alterations made on existing contour plans. They show proper drainage, aesthetics and it modifies the site in order to accommodate elements e.g. buildings Most common used intervals are 0.5, 1, 2 metres. PRINCIPLES Contours never cross one another. They never split They close on themselves: they don t simply end.
HACHURES Short disconnected lines drawn perpendicular to the slope and contour lines. Are more abstract and less exact as compared to contours They visually portray the steepness of the site; the closer and thicker they are the steeper. They are used to show shadowing, giving a 3d effect in landform representation. The darker and closer the hachures are the darker or inadequacy of light is being represented and vice versa.
Value and colour. This method utilises different shades or values of colour to express different heights of a landform. Model. A very effective way of expressing landforms as there is no room for miscommunication. Materials used ; clay,chipboard, Styrofoam. Disadvantages. Bulky. Time consuming. Expensive. Computer graphics. Helps with design as one can be able to design in both 2d and 3d views.
Ratio method. Percentage method.