TOWN PLANNING LECTURES BY RAVINDAR KUMAR: MAPS

AR-309: ARCHITECTURE AND TOWN PLANNING (B)

RAVINDAR KUMAR
Assistant Professor
Department of Architecture and Planning
NED University of Engineering and Technology
Karachi

LECTURE NO. 07
TOPIC: MAPS

Introduction:

The theme of current lecture is Maps. In the following a detailed description about maps is given for the understanding of students learning town planning.

What is a map?[1]

A map is a visual representation of an area or a symbolic depiction highlighting relationships between elements of that space such as objects, regions, and themes. Many maps are static two-dimensional, geometrically accurate representations of three-dimensional space, while others are dynamic or interactive, even three-dimensional. Although most commonly used to depict geography, maps may represent any space, real or imagined, without regard to context or scale.

Map Making or Cartography:[2]

Cartography or mapmaking is the study and practice of making representations of the Earth on a flat surface. Cartography combines science, aesthetics, and technical ability to create a balanced and readable representation that is capable of communicating information effectively and quickly.

History of Map Making:[3]

The earliest known map is a matter of some debate, both because the definition of "map" is not sharp and because some artifacts speculated to be maps might actually be something else. A wall painting which may depict the ancient Anatolian city of Çatalhöyük (previously known as Catal Huyuk or Çatal Hüyük) has been dated to the late 7th millennium BCE.[4]/[5] The ancient Greeks and Romans created maps beginning at latest in the 6th century BC. As early as the 700s, Arab scholars were translating the works of the Greek geographers into Arabic. In ancient China, geographical literature spans back to the 5th century BC. The oldest extant Chinese maps come from the State of Qin, dated back to the 4th century BC during the Warring States era. Early forms of cartography of India included legendary paintings; maps of locations described in Indian epic poetry, for example the Ramayana. Indian cartographic traditions also covered the locations of the Pole star, and other constellations of use. The Arab geographer, Muhammad al-Idrisi, produced his medieval atlas Tabula Rogeriana in 1154. He incorporated the knowledge of Africa, the Indian Ocean and the Far East gathered by Arab merchants and explorers with the information inherited from the classical geographers to create the most accurate map of the world up until his time.

It remained the most accurate world map for the next three centuries.[6] In the Age of Exploration from the 15th century to the 17th century, European cartographers both copied earlier maps (some of which had been passed down for centuries) and drew their own based on explorers' observations and new surveying techniques. The invention of the magnetic compass, telescope and sextant enabled increasing accuracy. In 1492, Martin Behaim, a German cartographer, made the oldest extant globe of the Earth.[7] In 1507, Martin Waldseemüller produced a globular world map bearing the first use of the name "America". Due to the sheer physical difficulties inherent in cartography, map-makers frequently lifted material from earlier works without giving credit to the original cartographer. By the 1700s, map-makers started to give credit to the original engraver by printing the phrase "After [the original cartographer]" on the work.[8]

In cartography, technology has continually changed in order to meet the demands of new generations of mapmakers and map users. The first maps were manually constructed with brushes and parchment and therefore varied in quality and were limited in distribution. The advent of magnetic devices, such as the compass and much later magnetic storage devices allowed for the creation of far more accurate maps and the ability to store and manipulate them digitally. In the late 20th century and early 21st century advances in electronic technology led to a new revolution in cartography. Specifically, computer hardware devices such as computer screens, plotters, printers, scanners (remote and document) and analytic stereo plotters along with visualization, image processing, spatial analysis and database software, have democratized and greatly expanded the making of maps.

Map types:[9]

In understanding basic maps, the field of cartography can be divided into two general categories: general cartography and thematic cartography. General cartography involves those maps that are constructed for a general audience and thus contain a variety of features. Thematic cartography involves maps of specific geographic themes oriented toward specific audiences. As the volume of geographic data has exploded over the last century, thematic cartography has become increasingly useful and necessary to interpret spatial, cultural and social data. An orienteering map combines both general and thematic cartography, designed for a very specific user community. A topographic map is primarily concerned with the topographic description of a place, including the use of contour lines showing elevation, Terrain or relief. A topological map is a very general type of map. It often disregards scale and detail in the interest of clarity of communicating specific route or relational information. “A topographic map is a detailed and accurate graphic representation of cultural and natural features on the ground. Topographic maps have multiple uses in the present day: any type of geographic planning or large-scale architecture; earth sciences and many other geographic disciplines which use highly detailed maps in its standard requirements.”

Maps for planning and development of urban areas:

Town Planning and allied professions have always been demanding suitable base maps as a prerequisite to any planning.[10] Maps are not new to town planners and engineers. However, preparation and use of large-scale maps, especially for urban areas, is not as good as in developed and other developing countries.

Maps are required by every Department/agency of the Provincial and Federal Governments having stake in development of urban area. Local authorities, public undertakings, service organizations require maps. However, the requirement of maps in terms of contents, quality and accuracy vary from organization to organization. Also, some organizations use maps every day while some use maps occasionally yet some others use maps once in a way. It is important to note that all the agencies aforementioned and others do not need comprehensive map, i.e. all the information in map. In the myriad of agencies involved in planning and development of towns and cities it is the agencies responsible for planning for physical development, which need maps most. Municipal authorities rank second in use of maps - comprehensive maps are required for planning and execution of works by engineering department, maps of buildings/plots for taxation and election purposes.

The institutions like urban development authorities, Local authorities - Engineering and Health Departments, Power Transmission and distribution agencies, Agencies for Urban Water Supply and Drainage system, Survey, Settlement and Land Records (City Survey) Department, Agencies for city transport system, Fire Force, Police Department - Traffic & Law and Order and Postal Department requires the maps on daily basis. Whereas; other institutions like Public Works Departments, National Highways Authority, Railways, Housing boards, Education Department, Health Department, Census Department and Election Commission requires the maps occasionally. Similarly the maps are required for different purposes. Full topographic maps at different scales are required by Urban Development Authorities for preparation/ revision of Comprehensive Development Plans, Zonal Plans (Sectoral Plans), Neighbourhood Plans, Sub-division Plans, Town Planning Schemes, etc. in the local planning area.[11]

The Scale of Maps:[12]

The scale of a map is the ratio of a single unit of distance on the map, to the equivalent distance on the ground.[13] Maps are sometimes referred to by relative descriptions of large scale or small scale. A large scale map displays objects so they appear relatively large. For example, an island displayed on a 1:10,000 map will appear larger than if displayed on a 1:100,000 map. Thus, the former is large scale. Maps with a ratio of 1:50,000 or larger (for example, 1:25,000 would be larger) are considered large scale. Maps with a ratio of 1:50,000 to 1:250,000 are considered medium scale. Any maps with a smaller scale (for example 1:500,000) are considered small scale.[14]

The scale of map to be used for a particular purpose in a project is determined as to what topographical features and what plan elements (details) are required to be shown with a certain degree of clarity on one or more sheets. Thus, to show a concept for circulation system and layout of plots in a sub-division plan (layout), in any urban area, a 1:2,000 scale map may be adequate. But, if details on plot numbers, entrance to plots, plot dimensions, centre line of roads, chamfers, asphalt, alignment of services like water, electricity and telephone, planting of trees, etc. are to be shown, maps at scale 1:1,000 would be needed. If the width of plot and roads is less than 10 m then a 1:500 scale map would be required to show all the afore cited details.

Process in planning - Best Practice:

Requirement of maps in terms of content, accuracy, scale, etc. in planning and development of urban areas can be appreciated well when the process involved in planning for physical development and implementation is known. Planning urban areas, especially metropolitan areas and cities, may have three stages, although they can vary:

Outline Development Plan (ODP) now re-christened as Perspective Plan, at macro (city/town) level;
Comprehensive Development Plan (CDP) also at macro level. This can also be called Master Plan;
Zonal Plans for part of city/town to elaborate the details; and
Town Planning Schemes at micro (local) level to implement the plan.

These levels are basically to perceive, conceptualize and see details from city/ town level to part of city/town and local level. These levels naturally require maps at different scales with different content with one or fewer maps to see the area under consideration.

For instance for planning a metro rail system or a bypass for rail or road, entire metropolitan area or city as the case may be has to be on only one or two sheets for all to see the alignment at metropolitan or city level. To fine tune the alignment, to avoid insurmountable obstacles, more and more details will be needed for which maps have to be at larger and larger scales. Only important features are shown on maps at small scale. All the features would be required at detail planning. What features in base map and what elements in plan proposal need to be shown on map user (planners, public and decision makers) determine the scale(s) for maps at a particular level.

Preparation of Master Plan:

Preparation of Master Plan at Metro/city level is highly complex and needs multi- disciplinary team of experts. However, the experts who steer the work on planning are the physical planners. Before embarking on making projections for demographic aspects to estimate the land required to meet the growth during the plan horizon, several studies are carried out by physical planners apart from other discipline. Most important planning survey is the use of building and parcels of lands, not only in the existing developed area but also in the vicinity, what is called Local Planning Area.

Planning studies:

Statutes on Town and Country Planning in all the States require preparation of Existing Land Use of every plot/property. Land uses are classified broadly in to 8 main groups. Not only that, a register showing the land use of every property need to be prepared and maintained along with the existing land use map. Hard copies of maps must be as large as 1:1,000 to mark the land use in field and to prepare fair maps in office; A GIS in deed, but in hard copy form.

Another planning survey for physical aspect is structural condition survey. This survey assumes importance in old areas due for redevelopment and/or rejuvenation. Structural conditions of buildings are classified in to 4 or 5 classes: very good, good, moderate, poor and obsolete. This survey is for structures for which each and every structure must clearly be available on maps to mark the appropriate condition in the field and to prepare fair maps in office. For this purpose also maps must be at least 1:1,000 if not at 1:500. This is yet another GIS earlier to electronic era.

All these maps need to be documented for reference and record, lest they are called for in courts of law. Large-scale maps show limited area on a sheet. They need to be generalized to prepare smaller scale maps: 1:5,000, 1:10,000, 1:20,000 to depict parts of urban area or the whole urban area on one or two sheets. The principle of Part to whole be applied which is similar to preparation of smaller scale maps from survey data at larger scale. Planning studies other than Land Use and Structural Condition are for:

Density of population/house holds;
House hold survey for social, economic conditions which is a sample survey;
Traffic and transportation survey;
Problems in physical condition like congested areas, narrow roads, bottlenecks, bad junctions, low lying areas, pollution from industry, etc.

All these surveys are not aimed at each and every property and maps at small scales, say 1:5,000, 1:10,000 and 1:20,000 may suffice. Analysis of the physical aspect - Land Use and Structural Condition - and socio-economic aspects, problems in physical form, function, need to be made and results shown on small scale maps: 1:5,000, 1:10,000 and 1:20,000. After the land requirement for future growth is established, land availability has to be analyzed for suitability for development. To show the results of the analysis as thematic maps also smaller scale maps, say 1:5,000, 1:10,000 and 1:20,000, area required. Result of each of the study on separate maps (transparencies) at smaller scale (all at same scale) will be compared with one above the other (sounds like GIS in place!) to synthesis the studies and draw inference. The maps showing the results of planning studies at small scales, on one or two sheets, are the basis on which alternative plans at macro level are conceptualized.

Concept plans:

Concept plans are free hand sketches on the base of accurate maps, at smaller scale (1:10,000 or 1:20,000 depending on the planning area) on one or two sheets, to show the boundaries of land areas for different uses, arterial and lower order road system, railway system, density of population/ house holds, etc. However, boundaries of proposed land uses and road system will not have any definite geometry.

Master Plan:

After a concept or combination of two or three is accepted, Master Plan (CDP) is prepared on accurate map at larger scales, say 1:20,000 or 1:10,000 (for Metros and large cities), and 1:5,000 for others.

Format of maps for Master Plan/Planning Drawings:[15]

Town planners, Architects and Engineers convert topographical maps in to working drawings to work on. They use the ISO A Series sheet formats for their drawings. Ammonia prints of drawings on A0 to A3 have to be folded to A4 size to have title block on top to go into files, storage, used in field and sent across by mail. Planning drawings must be in Landscape format. Planning drawings at any scale for any coverage must always be on base of scientifically prepared topographical map. Planning drawings will have legend and title block column at the right hand side of sheet from top to bottom. Column width can be 100 to 175 mm. Title block must be at bottom-right corner.

The drawings of Master Plan approved by Government are statutory and need to be preserved for long time. Album form is best to the purpose. Further, drawings must be compact and handy to go in to album without folding. For this purpose, A1 size (841 x 594 mm) is best both in album and handling on desk and in field. All the drawings in the Master Plan may be to A1 size in modular form. Topographical maps at scale 1:5,000 with an 800 x 400 mm format covering 4 x 2 km (8 sq km) fits within A1size with sufficient margin at bottom for full length for legend and title block and fit in a handy album.

Preparation of Zonal Plans:

The phase of Zonal Plan is between Master Plan and detail plan. Zonal plans are enlargement of Master Plan for part of city or town or for a particular land use zone. Zonal Plan include plan document to supplement the plan (drawing). Zonal plans may show even the minor roads but may not show individual properties which are very small. Maps for Zonal Plan must be at 1:2,000 to show all the details; but neither dimensions nor all properties. Town planners’ role does not end on preparation and approval of Master Plan and Zonal Plan at small scale to remain as wall maps for adoration. His role includes translating Master Plan/Zonal Plan in to Action Area Plans.

Preparation of Area Plan:

Area plans are action plans to implement the proposals in Master Plan. It may be for extension of city/town or rejuvenation or redevelopment of old and blighted areas. Master Plan is the basis for Area Planning. Maps for Area Plan start at the scale of Master Plan (1:5,000) to delineate the area for planning. Site plan at scale 1:1,000 will be required with additional survey data - cadastral boundary and topography and service cadastre. Maps may be in modular form. But, to see the concept (Master Plan content) for the whole area on one sheet site plan has to be at smaller scale. The Master Plan may be fine tuned on the accurate site plan.

Draft details plan, keeping the Master Plan concept as it is or with modifications, is prepared on a large scale, say 1:2,000, to show all the details in the plan - plots with numbers, roads, road elements like carriage way, centre line, junction details, plot dimensions, even entrance to plots, etc. Details plans may be in modular form. After the Draft Plan is approved detailed plan is finalized on maps at scale 1:1,000 to show all details and dimensions. Dimensions are also indicated to help setting-out and to prepare engineering designs. But, Plan is not fit for allotment of plots and for development. Physical planner’s responsibilities do not end after preparation of Master Plan at small scale. Physical planner must co-ordinate development as well not only organizing and overseeing setting-out of his plan on ground but also there after.

Conclusion:

Finally it is quite clearly spelled out that the understanding about maps is very significant and a prerequisite for the person involved in any town planning exercise.

TOWN PLANNING LECTURES BY RAVINDAR KUMAR

Friday, February 6, 2009

MAPS

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