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Indian Institute of Technology Delhi

Department of civil engineering

VIZAG City Trip generation and distribution byTransCAD

By

Narottam kumar - (2013 CEX 5534)

Tarun kumar meena (2013 CEX 55)

Tanu singh (2013 CEX 55)Praveen prakash (2013 CEX 55)

Submitted

To

Prof. Geetam Tiwari November 17, 2013

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Introduction

The only true comprehensive, transportation GIS System. A true vector-based GIS withcomprehensive mapping capabilities. Extensive econometric ability for travel demand modeling,(UTMS). Matrix-based Object Oriented Programming Language. Everything is contained in amain window. Data are shown and controlled in one or more windows. There are often severalways to perform a command. Status information and help are always available

Definitions:

Map : classically, a drawn or printed representation of the earth and its features. In this case, it is anelectronic version of that representation.

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Dataview : To view and edit tables of data from geographic, files, databases or spreadsheets

Matrix view : To view and edit values in a matrix.

Figure : A window containing a chart or other graphic

Layout : Presentations with maps, views and figures, plus freehand text and other items.

Layers : A group of map features of the same type, such as states, highways, or retail stores; conceptualequivalent of an acetate overlay on a physical map

Vizag City ModelThe map in the figure below shows Vizag city. The city is divided into 97 traffic analysis zones.

Figure 2: Vizag Layers

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Adding layer and labelling - Map has been taken from cd drive d where it is saved by opening new filefrom transcad. Then by adding layer of road on the map of vizag city we clearly seen on screen road anddifferent zones.

Choose Map-Initial Scale, then choose Map-Layers or click on the toolbar.Click Add Layer to display the File Open dialog box.

Then we have to require made centroid. Centroid is the center point of every zone . centroid is shown aspoint in every zone. As centroid is completed we have to require connmect it to roads by centroid

connector. Centroid layer is created by generating centroid layer from zone layer.

Create Centroids and Connectors.

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. a. Make the TAZ layer the active layer.b. Go to Tools>Export and click the Export as Centroid Points check box (saves a node at

the center of each TAZ into a node file). Make sure you select Standard Geographic fileformat (the default is compact) and call it centroids.

c. Add your Centroid layer, rename the layer Centroids and make it active (if it is notalready).

d. Use the TransCAD tools to automatically create centroid connecters ( Planning>PlanningUtilities>Centroid Connectors ), setting the maximum number of centroid connectors tobe 4 (default is 1) .

Trip Generation/ProductionTrip generation is the first step in the conventional four-step transportation forecasting process(followed by trip distribution, mode choice, and route assignment), widely used for forecasting travel

demands. It predicts the number of trips originating in or destined for a particular traffic analysis zone.

The goal of trip production is to estimate the number of trips, by purpose, that are produced ororiginate in each zone of a study area. Trip generation is performed by relating frequency of trips to thecharacteristics of the individuals, of the zone, and of the transportation network.

There are three primary tools that are used in modeling trip production, all of which are provided in

TransCAD:

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Regression Models A derived linear relationship between two or more related variables used to predict values of onevariable when given the values of other variables..

Discrete Choice Models Discrete choice models use disaggregate household or individual level data to estimate the probabilitywith which any household or individual will make trips. The outcome can then be aggregated to predict

the number of trips produced.

Cross-Classification

Cross Classification methods separate the population into homogeneous groups based on certainsocio-economic characteristics. Average trip rates are estimated for each classified group, therate depending on a zone statistic (e.g., trips/household). Once a zone or subset of a zone isclassified into a group, the zone statistic is multiplied by the appropriate trip rate to estimate thetotal trips generated.

Figure : Trip rates distiguted over the population

Input for cross classification-

Trip rate table Defines, for each trip purpose, the classifications used and the trip rates for eachclassification.Zone data table Contains information on the average values of the classification fields withineach zone.

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CREATING TRIP RATE TABLE-

CREATING CROSS CLASSIFICATION TABLE

TransCAD provides a procedure to create a trip rate table given disaggregate data(go to Planning>Planning utilities>Build cross-classification table)The user supplies the data, the classification fields and the classification ranges and

the procedure calculates average trip rates and variances for the rangesIn def ining classification fields and ranges, it is good practice to have homogeneitywithin ranges and heterogeneity between ranges.