Transportation System Planning

Effective transportation systems are essential for maintaining the productivity, health and safety of communities and regions. A transportation plan guides the investment in and timing of, improvements to the transportation network to meet community mobility, accessibility, safety, economic and quality of life needs.

Reasons to Prepare a Transportation Plan

Transportation plans are typically prepared to address the following items in a systematic, coordinated and comprehensive manner.

• Management of existing systems
• Maintenance of previous investment
• Realignment of existing services
• Introduction of new services
• Construction of new facilities
• Identification of ways to finance system maintenance and improvements

The process of preparing various transportation plans gives government agencies or elected officials to assess the adequacy of the existing system and to plan to meet future needs while maintaining local and regional transportation systems in good condition. The outcome of the process should be a transportation plan that defines existing problems and issues, predicts future deficiencies and problems, defines solutions and identifies where to find the resources needed to manage and implement plan recommendations. The goals of a particular transportation plan are usually determined by comparing existing transportation system performance to projected future demands and by considering the social, economic and environmental circumstances of the community. Transportation plans often provide a “blueprint” for future development and redevelopment in support of regional and comprehensive land use plans.

The development of a successful transportation plan requires the insights of those entities responsible for various components of the transportation system, working in concert with those who will use and be affected by the transportation service and improvements. Those responsible for plan development must create an effective forum for evaluating system deficiencies, assessing alternatives, and selecting the most effective course of action. Development of some plans is a highly structured process, complete with formal committees. Others are less structured and rely more heavily on exiting committees or informal communication networks to solicit participation.

Types of Transportation Plans

Transportation plans vary widely in approach, content and scope as determined by geographic coverage, scale and time frame. There are four basic types of transportation plans.

1. Statewide transportation plans
2. Metropolitan area long range transportation plans
3. Local transportation plans
4. Corridor plans

1) Statewide Transportation Plans

Statewide transportation plans, which are prepared by state DOTs (Department of transportation), provide the basis for coordinating data collection and analyses to support planning, programming and project development decisions. A basic requirement of plan development is coordination with the public and other entities with jurisdiction. The extent of coordination required with other transportation planning entities in developing the plan is based on the scale and complexity of many issues, including transportation problems, safety concerns, and land use, employment, economic, environmental, housing and community development objectives within the state.

The plans typically reference, summarize or contain information about the availability of financial and other resources needed to implement the plan. State plans are evaluated on a regular basis and updated periodically to reflect changing statewide priorities and needs. These are intermodal in nature. They address passenger, goods and freight movement for a minimum 20-year planning horizon. These plans are federally mandated to consider the following issues.

• Economic vitality
• Safety and security
• Accessibility and mobility
• Environmental quality
• Quality of life
• System connectivity
• System efficiency
• System preservation

2) Metropolitan Area Long Range Transportation Plans

Metropolitan area long range transportation plans focus on evaluating alternative transportation and land use scenarios to identify major travel corridors, assess potential problems and provide a basis for planning and programming major improvements. These plans cover multiple jurisdictions and are therefore “regional” in emphasis. Prepared under the direction of a federally designated MPO (Metropolitan Planning Organization), they typically cover a 20-year planning horizon. The plan must demonstrate the likely availability of funding sources needed to implement proposed programs and projects.

3) Local Transportation Plans

Local transportation plans are prepared either as stand-alone documents or as an element of a comprehensive plan. Local governments or regional transit providers typically prepare these plans, but they are coordinated closely with MPOs and state DOTs. The plans provide the basis for the programming and implementation of local transportation actions. They address small scale improvements and projects requiring major capital investments. The typical plan consists of an inventory of existing facilities and a description of existing conditions, an assessment of system deficiencies, a projection of future needs, a description of the proposed plan, discussion of cost implications and a summary of actions required for plan implementation. These plans usually address some short-range early action items (1 to 5 years), some midrange actions (5 to 10 years), and longer term activities in a 20-year time horizon.

4) Corridor Plans

Corridor plans that focus on transportation are prepared for high priority areas showing signs of congestion or predicted for significant future travel volume or for transportation facilities of historical or natural significance. The entity responsible for implementing the improvements most frequently prepares these plans. Coordination of corridor plans with the general public as well as with federal, state, and local agencies is required.

Corridor plans usually have a 20-year planning horizon. The degree of federal or state DOT participation is often governed by the proposed funding for the plan’s implementation. Corridor plans involve the definition of the corridor to be studied, along with a clear presentation of the problem to be solved. Consideration of a wide range of alternative will help to solve the identified transportation problem. These alternatives can involve different levels of investment or different types of corridor improvements. They are systematically evaluated using a set of stakeholder developed evaluation criteria. These criteria typically include land use, environmental effects, community concerns, cost, capacity and effectiveness. The analysis results are shared and discussed publicly prior to making a decision on a preferred course of action. The final plan document summarizes both the planning process and the results, explaining how the decision was made and the actions necessary to implement the plan.

Plan Components

Transportation plans should include the following elements.

• An overview of the planning process
• A description of existing conditions (transportation network and land use)
• A forecast of future conditions (transportation network and land use)
• A summary of transportation needs
• An assessment of transportation system capacity
• A series of alternative scenarios for future and proposed improvements
• A description of cost implications and funding sources
• Guidelines for implementation and performance monitoring
• A program for ensuring public involvement

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Types of Parks

Contemporary parks and open-space planning focuses on creating systems that respond to local values, needs and circumstances. The region of the country, physical setting, landscape features, demographics and socioeconomic characteristics are all determining factors in the form that a community’s park and open-space system. In each system, parks and open spaces are defined under various classifications that function individually and collectively to create a cohesive and balanced system. Successful parks and open-space systems are often planned around distinguishing landscape features or local themes that exhibit the unique qualities of a community.

Common to all systems is the notion of creating a high-quality living environment through the provision of parks, open spaces and recreational amenities. With such a broad spectrum of potential applications, the classifications for parks and open space are necessarily flexible and adaptable to the unique circumstances to which they are applied. The extent to which one type of park versus another is found within a system is determined by local needs and circumstances. In a metropolitan system, emphasis on neighborhood parks, parkways and large urban parks is common in response to the urban form and distinctiveness of individual neighborhoods.

Table : 1 Classification of Parks

Sl. No.	Classification	General Description
1	Neighborhood Park	Neighborhood parks are the basic units of the park system and serve a recreational and social purpose. Focus is on informal recreation.
2	Community Park	Serves a broader purpose than neighborhood parks. Focus is on meeting community-based recreational needs, as well as preserving unique landscapes and open spaces.
3	Large Urban Park	Large urban parks are generally associated with larger urban centers with large populations. Focus is on meeting wide-ranging community needs and preserving unique and sometimes extensive landscapes and open spaces.
4	Youth Athletic Complex/Facility	Consolidates programmed youth athletic fields and associated facilities to fewer strategically located sites throughout the community. Also can provide some neighborhood use functions.
5	Community Athletic Complex/Facility	Consolidates programmed adult and youth athletic fields and associated facilities to a limited number of sites. Tournament-level facilities are appropriate.
6	Greenway	Lands set aside for preserving natural resources, remnant landscapes and open space and providing visual aesthetics/buffering. Also provides passive-use opportunities. Ecological resource stewardship and wildlife protection are high priorities. Suitable for ecologically sensitive trail corridors.
7	Parkway	Linear park like transportation corridors between public parks, monuments, institutions and sometimes business centers. Can be maintained green space or natural in character.
8	Special Use	Covers a broad range of parks and recreation facilities oriented toward single-purpose uses, such as a nature center, historic sites, plazas, urban squares, aquatic centers, campgrounds and golf courses.
9	Park-School	School sites that are used in concert with or in lieu of, other types of parks to meet community park and recreation needs. School sites often provide the majority of indoor recreational facilities within a community.
10	Private Park/Recreation Facility	Parks and recreation facilities that are privately owned, yet contribute to the public park and recreation system.
11	Regional Parks and Park Reserves	Larger-scale, regionally based parks and open spaces that focus on natural resource preservation and stewardship.

1) Neighborhood Park

Neighborhood parks are the basic unit of the park system and serve a recreational and social purpose. Development focuses on informal recreation. Programmed activities are typically limited to youth sports practices and occasionally games.

2) Community and Large Urban Parks

Community and large urban parks are considerably larger in scale and serve a broader purpose than neighborhood parks. The main difference between a community and large urban park is that the latter is often associated with urban settings with large populations. Large urban parks also tend to be larger than community parks in order to provide more park space in a denser populated urban setting. The focus of both types of parks is on meeting wide-ranging community recreation and social needs. The facilities found within these parks are entirely based on community needs. Development focuses on both active and passive recreation, with a wide array of programmed activities often being accommodated. Special-use facilities are routinely located within these parks. This type of park also encompasses unique and extensive landscape features indicative of the region.

3) Youth and Community Athletic Complexes

Youth and community athletic complexes consolidate athletic facilities to strategic locations within a community to take advantage of programming efficiencies and economies of scale. Consolidation of athletic facilities also allows for a closer association between players, parents and coaches at scheduled events. Larger and fewer sites also provide greater conveniences, such as parking, restrooms and concessions and the capacity to generate revenue to offset operational and maintenance costs. Community athletic complexes are most common and serve both youth and adult athletic programs.

Youth athletic complexes are more common in larger metropolitan areas. In most cases, athletic complexes are heavily programmed with facilities to maximize land uses and operational efficiency. The type of facilities found within these parks is entirely based on community athletic program needs. With ever-changing recreational trends, greater emphasis is being placed on designing athletic complexes to be as flexible as possible without unduly compromising specific uses.

4) Greenways

Greenways are lands set aside for preservation of natural resources, remnant landscapes, open space and visual aesthetics. Greenways also provide passive-use opportunities, most often in the form of trails and nature centers. The key focus is on protecting ecological resources and providing wildlife corridors. Greenways can take various forms. In the broadest application, greenways form a network of interconnected natural areas throughout a community. They function as part of a border less system that links together parks, natural open spaces and trail corridors into a latticework of public space.

In this context, the line between greenways, parks, trails and the built environment is purposefully fostering the “city as a park” concept. Establishing an extensive continuous greenway system requires a close collaborative relationship between the city and development community in order to set aside the land for this purpose. Greenways can also take the form of a stand-alone land parcel dedicated to open-space preservation. These are often referred to as nature preserves or nature parks and often serve the same basic function as other forms of greenways.

5) Parkways

Parkways are best characterized as linear parks that also serve as transportation corridors between public parks, historic features, monuments, institutions and business centers. They often follow a notable landscape feature such as a creek or river.

6) Special-Use Parks

The special-use classification covers a broad range of parks and recreation facilities oriented toward single purpose or specialized use.

• Nature and cultural or performing arts centers
• Historic sites: downtowns, plazas, cemeteries, historic landscapes, churches and monuments
• Recreation facilities: aquatic centers, campgrounds, ice arenas, fitness centers, community centers, skateboard parks and stadiums
• Public gathering areas: amphitheaters, community commons, town centers and urban squares

7) Park-School

The park-school classification pertains to school sites used in concert with or in lieu of, other classes of parks to meet community park and recreation needs. In most cases, these sites are best suited for youth athletic facilities for school, district and community- based recreational programs. Park-school sites also often provide the majority of indoor recreational facilities within a community. To a lesser degree, school sites can also be used to service neighborhood park needs. The limiting factor is that most of these sites are heavily programmed for active uses and school buildings. This often leaves little space to accommodate neighborhood-focused amenities and create an aesthetically appealing setting that would draw families into the site.

8) Private Park/Recreation Facility

The private park/recreation facility classification covers a broad range of nonpublic parks and recreation facilities. This includes facilities such as golf courses, fitness clubs, museums, private courtyards, amphitheaters, horse-riding stables, water parks and miniature golf courses. This classification is provided as a means to acknowledge the contribution that a given private facility has to the public parks and open-space system within a community.

9) Regional Parks

The definition of a regional park varies considerably across the country. The common distinguishing feature is that regional parks typically service multiple cities and cross political jurisdictions. In many cases, a separate regional park authority is established to manage a series of regional parks. In some areas of the country, developers of regional parks focus on setting aside larger tracts of land to preserve natural resources, remnant landscapes and open space. A key objective is protecting ecological resources and providing wildlife habitat. Passive uses, such as hiking, canoeing and nature viewing are most common forms of activities.

The primary distinction between this type of regional parks and greenways is scale and service area. Regional parks are typically at a much larger scale (in land area) than greenways. In other areas of the country, regional parks are an extension of the large urban park classification. In addition to preserving natural resources and open space, these parks also provide active recreational areas, gardens, picnic facilities and other forms of special use. In parts of the country, regional parks include major national monuments and historic landscapes.

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Development Control Regulations (DCR)

Development Control Regulations are a set of rules that are planned to ensure the proper and effective development of a city, as well as the general welfare of the public. Regulation is necessary to ensure planned development. It depends on a “plan-led system” whereas development plans are made and the public is consulted. DCR govern the urbanization of a city and ensure efficient growth and the general welfare of the public. These regulations aim to provide basic needs to the public such as health, safety, convenience, economy and amenity. 

It is a mechanism that controls the development and use of land. This involves the construction of new buildings, the extension of the existing ones, reducing the misuse of land and the change of use of the building or land to another use. Developing new houses/industrial buildings/shops are important for supporting economic progress. At the same time, it is also necessary to protect or improve the quality of towns, villages, countryside, etc. 

Objectives of the Development Control Regulations 

• To stop the unfavorable demand and misuse of land. 
• To assist private interest along with public interest in all phases of development. 
• Development control is legal in nature and the planning authority has the power to punish the defaulters. 
• To control and limit overcrowding on land. 
• To control the private development as per the required rules in connection to public safety, health, and convenience. 

Types of Development Control Regulation (DCR) 

1. Town and country planning act 

It involves the creation and implementation of strategies to provide better infrastructure for people. 

2. Zoning regulations act 

It deals with the allocation of land for specific purposes and keeping a check on the use of land and the construction norms.

3. Slum clearance act 

The major focus is on reducing the number of slums and ensuring the rehabilitation of inhabitants. 

4. Building bye-laws 

These are a set of regulations imposed on developers, which must be mandatorily met during construction. 

5. Periphery control act 

The purpose is to protect peripheral land that comes under the jurisdiction of a State from all sorts of encroachments and illegal use. 

6. Land acquisition act 

Acquiring land for governmental projects and compensating the landowners appropriately. 

Controllable Factors under DCR 

1. Floor Space Index (FSI) 

It is the ratio of the covered area of a building or the built-up area to the area of the plot on which the building is meant to be built. Floor Space Index is the total area (including all floors) that can be built upon a plot, leaving the remaining as open space. It is authorized by the government for a particular locality. It is sometimes termed as Floor Space Compensation Ratio (FSR), Floor Area Ratio (FAR), site ratio or plot ratio. FSI rules are usually based on the National Building Code. 

As per the new rules, balconies, flower beds, voids and niches are calculated in FSI, and to compensate for the loss, the government has permitted fungible FSI up to 35 percent for residential and 20 percent for commercial developments. 

2. Parking space 

There is a specified space for parking in residential, commercial and educational institutions as per the defined rules in different States. However, as per the norms, parking size should be a minimum of 2.5 m x 5.5 m (motor vehicle), 1.2-3 sq m (two wheeler), 3.75 m x 7.5 m (transport vehicle)

3. Size of plots 

As per the DCR, the size of plots appropriate for residential development ranges according to the income level of occupants. The ideal size requirements under DCR are -

• Low-Income Group (LIG) – 135 sq m to 180 sq m
• Mid-Income Group (MIG) - 216 sq m to 360 sq m
• High-Income Group (HIG) - 486 sq m to 972 sq m 

4. Lifts 

A building with a height of more than 13 m must have a lift from the ground floor. The minimum capacity of the lift should be six persons. 

5. Fire Safety 

Buildings exceeding three floors need a certificate of approval from the Fire Department. Moreover, every floor with more than 150 sq m of floor area and a capacity of over 20 people should have at least two doorways, along with a staircase for the fire exit. 

6. Structural design and services 

The architectural design should be made as per the prescribed norms of the National Building Code (NBC) of India. The building must possess plumbing facilities, protection from lightning, electrical installation and air-conditioning, to name a few. 

Development Control Regulations in India’s Top Cities 

1. Development Control Rules, Mumbai 

In January 2012, the Maharashtra Government had announced amendments to the Development Control Rules for Mumbai with the prime objective of bringing in transparency and reducing temporary and discretional decision-making at different levels. The new rules mean pricing based on maximum available FSI, reducing the risk that was largely accepted earlier with regard to excessive saleable area.

Under the new DCR, areas for balcony, flower-beds, stairs, terraces, corners, voids would be counted in the FSI but these were not considered in FSI calculation earlier. 

With the new rule, plots measuring over 2,125 sq.m.(22,873 sq.ft.) will now be permitted to build more, vertically. As per the new regulation, the Brihanmumbai Municipal Corporation (BMC) will calculate the development potential of a plot on its gross area, without decreasing the area reserved for recreational purposes. The developers will now be able to build more apartments in a building with a proportionate increase in the open spaces in the building. 

Every plot, where a residential structure is coming up will have to reserve 15% of land for open spaces known as recreational ground. Earlier, according to the 1967 and 1991 DCR, when the BMC calculated the development potential of a plot, the reserved 15% plot was deducted. This resulted in a lesser number of flats being constructed. However, the BMC will determine the development potential including the reserved space now with the new rule. Resulting in permitting builders to develop more in the specified Floor Space Index or FSI. 

2. Development Control Rules, Chennai 

The State government has issued a Government Order, revising the 2nd Master Plan of the Chennai Metropolitan Area and the Development Control Regulations in other parts of the State. This is only for residential buildings that will reduce the cost of housing for low-income groups. 

The Tamil Nadu government has increased the maximum Floor Space Index (FSI) for multistoried residential buildings from 2.5 to 3.25. 

According to the amended terms on ‘premium FSI’, a multistoried residential building will get the maximum FSI of 3.62 on the payment of premium charges. The maximum FSI for specific buildings in the residential category and ordinary residential buildings will be 2. 

The Development Control Regulations 26 of the Chennai Metropolitan Area has been revised to change the FSI for special buildings also from 1.5 to 2 for continuous building areas. 

Likewise, the Development Regulations 27(3)D of the Chennai Metropolitan Area has been revised. 

The Chennai Metropolitan Development Authority (CMDA) will also allow premium FSI over and above the usually permissible FSI subject to a maximum of 1.62. Now, the maximum FSI for a multistoried building will be 3.62 using premium FSI.

For a road width of 18 meters, the premium FSI permissible will be 50%. For roads with a width of 12-18 meters, the premium FSI permissible will be 40% and for roads with a width of 9-12 meters, it will be 30%. 

Factors contributing to non−compliance of the development control regulations in India 

1. Failure of planning process to take account of ground realities and reset the planning guidelines, thus resulting in supply side shortages in terms of legitimate spaces for various land uses. 
2. Weak enforcement machinery is responsible for the non-implementation of building laws and regulations. Implementation of development policies has been characterized by delays and poor execution of projects and programmes by nodal service providing agencies, lack of institutional and inter-sectoral coordination framework for development planning and the inadequate participation by the beneficiary population. 
3. Unrealistic and cumbersome regulations including complex development control norms and building byelaws along with long drawn approval. 
4. Absence of proper standing of institutional mechanism for seeking justifiable modifications/ relaxations in the existing building code and land use regulations. In recent years, there has been considerable debate and criticism leveled at the management of local government and legal system as it does not provide for quick and apt resolutions of building violation issues, which result in delays and misuse of the system. 

Ways to improve the enforcement of development regulations 

• Simplification of development control requirements by simplifying procedures and introducing appropriate policies/ zoning regulations while safeguarding the health and environment and not damaging the economic base of the activities concerned. 
• Revisiting the principles on which development control is based. As in case of zoning systems, certainty for developers is achieved at the cost of inflexibility for unforeseen demands and needs; while in discretionary systems flexibility to accommodate rapid and unforeseen changes comes at the cost of uncertainty and greater opportunities for corruption. It has been recommended that a system needs to be evolved to achieve a workable compromise between these principles.
• Strengthening the enforcement capacity to monitor and take action on illegal developments and violations of development controls. In order to improve the efficiency and effectiveness of development controls, it is important that rather than devoting resources to improving the quality of urban spatial plans and development regulations, urban managers should concentrate on governance. It is necessary to make the whole system of plan formulation and implementation more dynamic and responsive to changes. For this, the planning legislation will have to be modified, updated and made more citizens friendly.

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Methods Of Making A Base Map

There’s a couple of ways you can make a base map: 

1. Trilateration – the most low tech, effective solution 

2. Tracing an aerial photo at scale 

3. Using software to make a digital base map 

1) Using Trilateration to Make a Base Map 

Trilateration is the process of determining the locations of points by measurement of distances, using the geometry of circles and triangles. Trilateration is an easy way to survey a small block of land or a back yard. It does not require special training and only requires a few inexpensive tools. Tools which will need for trilateration: 

In the field: 

1. A tape measure (20 m long is usually enough) 

2. A sketch pad or grid paper for recording your measurements 

3. Some drafting pencil or pens. 

Back inside 

1. A nice large sheet of paper to make your base map on 

2. Some drafting pencil or pens. 

3. A drawing compass (Preferably with an extension arm) 

4. A scale rule 

2) Tracing an Aerial Photo at Scale 

It is one of the quickest ways is to project a satellite image or aerial photo onto your paper and trace it. To do this: 

• Choose an image with a scale bar visible e.g. in the bottom right 
• Choose the scale by adjusting the zoom of the projector (or moving it closer or further from the wall) until the site fits on the page and the scale bar measures true on a scale ruler 
• Read the scale off the ruler (e.g. 1:50) 
• Trace the major features off the projection onto the page. 

3) Creating a Digital Base Map 

Another way is to use software on a computer to create a digital base map from a satellite image or aerial photo. 

Base map is a layer with geographic information that serves as a background. A base map provides context for additional layers that are overlaid on top of the base map. Base maps usually provide location references for features that do not change often like boundaries, rivers, lakes, roads, and highways. Even on base maps, these different categories of information are in layers. Usually a base map contains this basic data and then extra layers with a particular theme or from a particular discipline, are overlaid on the base map layers for the sake of analysis. 

Some base maps look like Vector Layers but are actually tiled Raster layers. Tiled images are used because they display faster and deliver a good combination of layers for providing context and orientation. If your base map has raster layers, you cannot turn the layers off and on. For example, if you wanted to show all the different types of endangered plants within a region, you would use a base map showing roads, provincial and state boundaries, waterways and elevation. Onto this base map, you could add layers that show the location of different categories of endangered plants. One added layer could be trees, another layer could be mosses and lichens, another layer could be grasses.

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Base Map Preparation Process -2

Natural and cultural features that are relatable to a cadastral parcel form the next most important levels of base map data. One of these levels includes all streets, roads, railroads and airports, with their associated names. Another level includes all permanent buildings and other structures greater than a specified size. A third level includes all water features such as perennial and intermittent streams, natural and man-made lakes and ponds, reservoirs, canals and aqueducts and their associated names. A fourth level includes boundaries of civil (Governmental) jurisdictions at all levels: state, county, city and township. Other secondary levels of natural and cultural features, such as contours. floodplains, wetlands, vegetation cover, land use, and utility lines, may be included selectively in the base-map composite. 

Use of a number of different levels or overlays of base map data is essential to provide flexibility in meeting the different requirements of different map users. Drafted overlays must be precisely registered in position to each other as illustrated in Fig. A planner may desire, for example, to use as a working base a composite of the land use, floodplain and base map overlays. The greatest flexibility in base map content, to satisfy user requirements, is in digital mapping. Map information can be separated digitally into a maximum number of data levels, updated most efficiently, and plotted precisely on a single base sheet using any specified number of data levels as required. At the same time, standards and procedures must yet be established to control the level of map content detail as map scale is changed over wide ranges. 

Overall, the base map that supports a multipurpose cadastre must provide as a minimum enough planimetric detail for locating ownership boundaries referenced to natural features, such as stream and lake shorelines or to man-made features not as yet tied to the coordinate system, such as highways and railroads. Desirably, it should show all objects related to the location of real property boundaries, such as fences or driveways, at reasonably frequent intervals.

Fig  A registered overlay system

Accuracy of the horizontal and vertical position information on the base map is fundamentally a function of the map scale and contour interval, respectively. National Map Accuracy Standards have long been used as the primary standard to control the accuracy of plotted map information. For scales larger than 1:20,000, which include essentially all base maps that would be used to support a cadastral overlay, standards for horizontal accuracy specify that 90% of the points tested shall be plotted on the map within 1/30 inch of their true position. Standards for vertical accuracy specify that 90 % of the points tested shall be shown in elevation within one half of the contour interval used on the map.

The Photogrammetry for Highways Committee of the American Society of Photogrammetry has prepared specifications for large-scale mapping for highways, with a horizontal accuracy requirement that 90% of all planimetric features be plotted within 1/40 inch of their true position. This is a more stringent requirement than the comparable 1/30 inch required by National Map Accuracy Standards and has also been suggested by the Task Committee for Photogrammetric Standards of the American Society of Photogrammetry in their recently proposed accuracy specifications for large scale line maps. Either the 1/30 inch or 1/40 inch requirements have been adopted by nearly all users in their base mapping specifications for large scale property ownership maps. 

The requirement that the base map of a local record system be compiled according to National Map Accuracy Standards is primarily due to the need for the base map to satisfy the engineering needs of public works departments. When accurate information is necessary, specific boundary lengths would come from a recorded plat, boundary description or other report of survey, not from scaling the cadastral overlay on the base map. A new Engineering Map Accuracy Standard has been proposed by the Committee on Cartographic Surveying of the Surveying and Mapping Division of the American Society of Civil Engineers (ASCE). These standards are intended to provide a clearer communication of accuracy requirements between those having the need for the map and those preparing the map. Also included are specific field testing procedures to assess the compliance of the map with the standards. 

The scale of the cadastral map system is principally a function of the size of the predominant land parcel. This criterion generally corresponds to the level of land value or degree of urbanization. Listed in Table 1 are the scales that have been selected almost universally for each type of area. Contours may only need to be included on the base map for specific users with a requirement for topographic detail. The added expense is substantial. Contour interval would be selected in conjunction with the map scale, the terrain relief, and the elevation information requirements. Typical combinations are listed in Table 2.

Table 1 Suggested base map scale

Table 2 Appropriate contour intervals for suggested map scale

Necessities of a Base Map 

• To give a place to record our observations and interpretations of the site
• To give us a canvas for drawing our concept, schematic and detailed designs
• To reduce the time we have to spend redrawing the permanent elements of the site 
• To provide consistency between the different plans & drawings we are going to present to other people It gives us a not quite “blank canvas” that we can quickly duplicate
• Because we can easily make many copies, it frees up our creativity to experiment and not care so much if we make a mistake

Choosing a Scale 

A scale drawing shows a real place with accurate sizes reduced by a factor (called the scale), to allow us to represent real objects and features on a piece of paper. Scale depends on the size of area, size of paper, amount of detail to draw. Use the equation 

Desired Scale = Width of area in centimetres/Width of paper in centimetres 

Then round the scale to the nearest 1,000. 

Changing Scale of Base Maps 

If enlarging by photocopy machine: – enlarging by 200% doubles the size of the map and halves the scale. Calculate with this equation 

 Percent enlargement = (Scale of original/Target scale) x 100%

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