# Time–distance diagram

Last updated

A time–distance diagram is generally a diagram with one axis representing time and the other axis distance. Such charts are used in the aviation industry to plot flights, [1] or in scientific research to present effects in respect to distance over time. Transport schedules in graphical form are also called time–distance diagrams, [2] they represent the location of a given vehicle (train, bus) along the transport route. [3]

## Contents

In project management, a time–distance diagram (also called time-chainage diagram, time–distance chart, time-chainage chart, time–location diagram, time-location chart, March chart, location–time chart, orthogonal diagram, line of balance chart, [4] linear schedule or horse blanket diagram [5] ), is a method of graphically presenting a time schedule for all types of longitudinal projects such as pipeline, rail, bridge, tunnel, road, and transmission line construction.

Activities in time–distance diagrams are displayed both along a time axis and along a distance axis according to their relative linear position. This allows showing not only the location of the activity but also the direction of progress and the progress rate. Activities can be presented as geometrical shapes showing the occupation of the work site over time such that conflicting access can be detected visually. Different types of activities are differentiated by color, fill pattern, line type, or special symbols. A symbolic drawing along the distance axis is often used to improve the understanding of the time–distance diagram.

The advantage of a time–distance diagram is that it nicely shows all visible activities along the construction site on a single diagram.

## Layout

A time–distance diagram is a chart with two axes: one for time, the other for location. The units on either axis depend on the type of project: time can be expressed in minutes (for overnight construction of railroad modification projects such as the installation of switches) or years (for large construction projects); the location can be (kilo)meters, or other distinct units (such as stories of a high-rise building).

Normally, the time axis is drawn vertically from top (start of project) to bottom (end of project), and the location axis is drawn horizontally. The direction of the chainage is usually chosen with consideration of geographical position of the project, with the numbers either increasing or decreasing. The location axis is often enhanced with a schematic of the construction project. Other, location-specific information (aerial photos, cross-sectional views) can be added to enhance the visualization of the work site.

A legend explaining the meaning of the various colors, symbols and line types used in the chart may be included in the time–distance diagram. Other information shown may be cost and resource histograms along the time axis.

The drawing area may contain grid lines to ease comprehension of the chart: hours, days, weeks, months, years, for the time axis; equidistant units along the distance axis or specific locations (piles, stations, foundations, etc.). The background of the drawing area may be enhanced with time and location related information such as close seasons, hold-off intervals, meteorological data (rain/snow fall, temperatures).

The project activities are placed within the drawing area according to their specific nature:

• Simple activities such as cable pulling, fencing, road surfacing can be drawn as a single line: The work crew starts on a given location at a given time and continues with linear progress. Exhibit 1 shows two such activities: Activity 1 starts in Week 1 on Day 3 from km 0+000 and continues until Week 2, Day 13, progressing until km 1+100. Activity 2 starts the next day at km 2+000 and continues until Day 19 to km 1+100. These two activities could be performed by a single work crew as the second activity starts right after the first.
• When an activity in a specific area takes a considerable time, the activity would be drawn as a rectangle with the sides of the rectangle corresponding to the length of the work site (along the distance axis) and the amount of time needed (along the time axis). Examples of this type of work would be the installation of equipment (power substation) or the construction of retaining walls. Exhibit 2 shows such an activity in the area from km 1+100 until km 1+300, starting on Day 2 with a duration of 14 days.
• Activities which occupy a constant length of the line during a specific work period (assuming constant progress) would show as staggered line. Exhibit 3 demonstrates such an activity which starts in the area from km 1+900 to km 2+000 and requires one day to complete before the work crew moves towards the next line section (km 1+800 to km 1+900) to work there for one day.
• More complex activities will be drawn (such as overhead catenary installation) as parallelograms showing exactly during which time the line section is occupied by the work crew. Such an activity is shown in Exhibit 4 where the work starts on Day 8 and continuing until Day 21. The work crew occupies 300 m of the site during each day.
• The progress rate can be recognized by the slope of the activity along the time axis: Slow progress would show as steeper incline, fast progress would show a moderate incline. In Exhibit 1, Activity 1 has a progress of 100 m per day (1,100 m in 11 days), Activity 2 has a progress of 150 m per day (900 m in 6 days).
• Depending on the direction of the work, an activity line would decline or incline towards the completion date.
• If the progress of an activity would depend on location specific parameters (such as soil removal), the activity would show as non-linear line. Exhibit 5 shows such an activity.
• Even more complex graphics are produced when the progress rate considers specific work times (shifts, holidays, and off-periods). Exhibit 6 shows activities from previous exhibits but this time having no progress on the weekend days (Day 7 of each week).
• When planned activities are displayed as lines, actual and forecast progress can be mapped as dotted or dashed line on the same axes to provide actual vs planned progress. [6]

Annotations such as boxed text and activity labels within the drawing area improve the level of information.

 Exhibit 1: Two linear activities Exhibit 2: Single activity at a single location Exhibit 3: Staggered activity Exhibit 4: Parallelogram activity Exhibit 5: Non-linear activity Exhibit 6: Activities with no-work periods

## Tools

Time–distance diagrams can be created using any kind of drawing tool, certainly one which allows scaled drawing (for example, CAD editors, Visio). Sometimes, spreadsheet tools are employed where the width of the columns and the height of the rows form the distance and time scales.

However, in real project life, a time schedule needs to be adjusted continuously: This is when the use of specialized tools quickly brings out their advantage. These tools (see External links below) are project management tools in their own right with an emphasis on the ability to present the time schedule as time–distance diagram. Activities can be edited using project management terminology plus all drawing attributes for the activity's shape. Special features allow dependency links (with lags), complex scaling, access conflict detection, resource-dependent progress, and more. Most often, such tools provide various interfaces to other project management software, at least to import and export activity information. Complex systems (such as TimeChainage, DynaRoad, TILOS or Time Location Plus) even integrate into commonly used project management software (Primavera, Microsoft Project, Asta Powerproject).

## Related Research Articles

Project management is the process of leading the work of a team to achieve all project goals within the given constraints. This information is usually described in project documentation, created at the beginning of the development process. The primary constraints are scope, time, and budget. The secondary challenge is to optimize the allocation of necessary inputs and apply them to meet pre-defined objectives.

Project planning is part of project management, which relates to the use of schedules such as Gantt charts to plan and subsequently report progress within the project environment. Project planning can be done manually or by the use of project management software.

A chart is a graphical representation for data visualization, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart". A chart can represent tabular numeric data, functions or some kinds of quality structure and provides different info.

The critical path method (CPM), or critical path analysis (CPA), is an algorithm for scheduling a set of project activities. It is commonly used in conjunction with the program evaluation and review technique (PERT). A critical path is determined by identifying the longest stretch of dependent activities and measuring the time required to complete them from start to finish.

Project management software (PMS) has the capacity to help plan, organize, and manage resource tools and develop resource estimates. Depending on the sophistication of the software, it can manage estimation and planning, scheduling, cost control and budget management, resource allocation, collaboration software, communication, decision-making, quality management, time management and documentation or administration systems. Numerous PC and browser-based project management software and contract management software products and services are available.

The program evaluation and review technique (PERT) is a statistical tool used in project management, which was designed to analyze and represent the tasks involved in completing a given project.

A Gantt chart is a type of bar chart that illustrates a project schedule, named after its popularizer, Henry Gantt (1861–1919), who designed such a chart around the years 1910–1915. Modern Gantt charts also show the dependency relationships between activities and the current schedule status.

In project management, a schedule is a listing of a project's milestones, activities, and deliverables. Usually dependencies and resources are defined for each task, then start and finish dates are estimated from the resource allocation, budget, task duration, and scheduled events. A schedule is commonly used in the project planning and project portfolio management parts of project management. Elements on a schedule may be closely related to the work breakdown structure (WBS) terminal elements, the Statement of work, or a Contract Data Requirements List.

A project network diagram is a graph that displays the order in which a project’s activities are to be completed. Derived from the work breakdown structure, the terminal elements of a project are organized sequentially based on the relationship among them. It is typically drawn from left to right to reflect project chronology.

Linear referencing, also called linear reference system or linear referencing system (LRS), is a method of spatial referencing in engineering and construction, in which the locations of physical features along a linear element are described in terms of measurements from a fixed point, such as a milestone along a road. Each feature is located by either a point or a line. If a segment of the linear element or route is changed, only those locations on the changed segment need to be updated. Linear referencing is suitable for management of data related to linear features like roads, railways, oil and gas transmission pipelines, power and data transmission lines, and rivers.

Construction management (CM) is a professional service that uses specialized, project management techniques to oversee the planning, design, and construction of a project, from its beginning to its end. The purpose of Construction management is to control a project's time / delivery, cost and quality—sometimes referred to as a project management triangle or "triple constraints." CM is compatible with all project delivery systems, including design-bid-build, design-build, CM At-Risk and Public Private Partnerships. Professional construction managers may be reserved for lengthy, large-scale, high budget undertakings, called capital projects.

Task management is the process of managing a task through its life cycle. It involves planning, testing, tracking, and reporting. Task management can help either individual achieve goals, or groups of individuals collaborate and share knowledge for the accomplishment of collective goals. Tasks are also differentiated by complexity, from low to high.

A burndown chart or burn down chart is a graphical representation of work left to do versus time. The outstanding work is often on the vertical axis, with time along the horizontal. Burn down charts are a run chart of outstanding work. It is useful for predicting when all of the work will be completed. It is often used in agile software development methodologies such as Scrum. However, burn down charts can be applied to any project containing measurable progress over time.

Linear scheduling method (LSM) is a graphical scheduling method focusing on continuous resource utilization in repetitive activities.

A glossary of terms relating to project management and consulting.

The project management triangle is a model of the constraints of project management. While its origins are unclear, it has been used since at least the 1950s. It contends that:

1. The quality of work is constrained by the project's budget, deadlines and scope (features).
2. The project manager can trade between constraints.
3. Changes in one constraint necessitate changes in others to compensate or quality will suffer.

Construction surveying or building surveying is to stake out reference points and markers that will guide the construction of new structures such as roads or buildings. These markers are usually staked out according to a suitable coordinate system selected for the project.

DynaRoad is a project management software for heavy civil engineering projects. It is used for planning the mass hauls of an earthworks project, creating a construction schedule, and monitoring the progress of the project.

The following outline is provided as an overview of and topical guide to project management:

## References

1. Aeroplane and commercial aviation news, Volume 87, 1954
2. Chakroborty, Partha; Das, Animesh (2004). Principles of Transportation Engineering. PHI Learning Pvt. Ltd. p. 89.
3. Gallo, M.; D'Acieerno, L.; Montella, B. (2011). A multimodal approach to bus frequency design. Urban Transport XVII: Urban Transport and the Environment in the 21st Century. Vol. 116. WIT Press. p. 220.
4. Emmitt, Stephen (2007). Design management for architects. Wiley-Blackwell. p. 97. ISBN   978-1-4051-3147-6.
5. "Topcon Project Management Pages". topconplanning.com. Archived from the original on 2015-04-02.

from projects using time-distance diagrams)