(Geospatial) computing in civil engineering

Ari Jolma12.4.2007

Materials

Miles & Ho 1999: Applications and Issues of GIS as Tool for Civil Engineering Modeling. J.Comp.Civ.Eng. Volume 13, Issue 3, pp. 144-152Venigalla & Casey 2006: Innovations in Geographic Information Systems Applications for Civil Engineering. J.Comp.Civ.Eng. Volume 20, Issue 6, pp. 375-376Wikipedia pages: GIS, CAD, Building Information Modeling, ...Peachavanish et al 2006: An ontological engineering approach for integrating CAD and GIS in support of infrastructure management. Advanced Engineering Informatics 20 (2006) 71–88

Civil engineering

a broad field of engineering dealing with the planning, construction, and maintenance of fixed structures, or public works, as they are related to earth, water, or civilization and their processesFundamentally, we as civil engineers—regardless of emphasis— share one characteristic in that we are all problem solvers.

Problem solving cycle

DefinitionStructuringDefining possible solutionsEvaluation of solutionsDecision makingImplementation

Design

Simulation,optimization

Modeling

What are problems?

G Polya: How to solve it (from M Jackson: Software requirements and specifications)

ideas for solving mathematical problems from ancient Greeks

the first people in Western world to think systematically about how to solve problems

(1) problems to prove, (2) problems to find Each problem has principal parts and a solution task (1): parts are hypothesis and conclusion (2): parts are unknown, the data, and the condition

Fitting a problem into a particular frame is a primary activity in understanding any problem

Domain characteristics

The characteristics of the (CE) context of the problemCharacteristics of the data and information that the CE professional has to manage computationallyTangible vs intangibleDynamic vs staticSpatial vs aspatial...

Design cycle

Conceive (innovate)DesignDevelopBuild / manufactureOperate / maintain

Model

Drawings

A design is a solution

A CE design may be a structure a plan

which may include also structures a management procedure an operational procedure

Computing

1. Manage acquired data and information

that is from outside sources that is made within the project /

organization

2. Produce required/useful data and information products

to match generic methods to match specific needs of people

GIS

Geospatial softwareVarying origins/foci Cartography One or more methods Resource management Management of geospatial data

Brief history of GIS 1

60’s Tomlinson: CGIS

land-use management, resource monitoring Laboratory for Computer Graphics and Spatial

Analysis at the Harvard Graduate School of Design

70’s Commercial mapping applications sold by

vendors

80’s Personal computer: interaction, new application

areas

Brief history of GIS 2

90’s Tomlin: cartographic modeling GIS and hydrological modeling Increasing commercialization

2000 Web, spatial data infrastructures

GIS and CE 1

Benefits Capture, store, and manage

geospatially referenced data in common formats

Visualization capabilities for information and verification

Common methods to compute information from Digital Elevation Models (DEM)

GIS and CE 2

Problem areas The mismatch between CE specifics

and generic GIS capabilities The common GIS data model is

generic and simple -> difficulties in applying CE specific data models

Linking of CE (simulation) models with GIS that lack the concept of temporal data

The GIS data model

Thematic layersFeatures sharing a similar set of attributes feature = spatial object + record of attributes

Common spatial representations points, polylines, polygons, rasters

Topological relationships it is common to not to specify these explicitly

A CE data model (an example: water management plan)

Hydro system description and operation objectives: flood control, storage,

ecology, ...

Monitoring system and operationLoads and associated permits and requirements etc.Other actions and measures

CAD

A computer-based design toolCommonly used, e.g., in Architecture, Engineering, and Construction for creating plans and drawings

2D drafting / 3D solid modeling

The CAD data model

A mathematical model for describing arbitrary (smooth) curves and surfaces Boundary representation

topology (faces, edges, vertices) + geometry

compare to GIS data model!

NURBS non uniform rational B-spline

CE and CAD 1

Benefits Create engineering drawings and

visualizations Simulation of designs Output of design data to

manufacturing utilities Maintain libraries of parts and

assemblies

CE and CAD 2

Problem areas (If there is a) focus on drawings and

not in the data model Interoperability problems, especially

caused by proprietary file formats

GML, LandXML, IFC, ...

A shared data model is a key to interoperability that is an important requirement as CE projects are often large and involve many participantsData and information exchange between organizations between planning tools and equipment

Based on XML (Extensible mark-up language) Object-orientation Ontologies

Data in an information system

Organized structure (data model) Efficient update and querying

also complex updates and queries standards-based update and querying employs advanced algorithms!

Remove redundancy within one data base within organization

A single shared/forced structure Management objectives

security, integrity, ... Support discovery

State-of the art solutions

RDBMS relational database management systems

data is in tables, tables have columns (fields) and rows (tuples), columns have a field name, field data type, ...

columns between tables may be linked SQL

structured query language

OODBMS Object-oriented database management systems

data is stored as objects, objects have a class, a class has attributes and methods, attributes have names and data types

classes may have various types of relationships

Data in messages

Messages are a means of communicationIn computing

human<->human (not directly, via a computer system)

human->program program->human program<->program

Semantics Syntax

construction of complex signs from simpler signs Pragmatics

how signs are interpreted in particular circumstances or context

State-of-the-art computational solutions

Derivatives of SGML standard generalized markup language HTML, XML

Typesetting and document formats LaTeX, .doc, RTF, ...

All other file formats Shapefile, DGW

All program to program protocols ODBC (open database connectivity), ...

Everything else SQL, ...

Digging still deeper...

Descriptions raw material for databases raw material for message structures raw material for problem solving raw material for program development

The suitability of a description is judged by the purposeDescriptions are organized thoughts the level of organization may vary

Descriptions are not specifications

State-of-the-art solutions

Predicate logic extension of propositional logic logic with generalized facts

Jackson: designations, definitions, refutable descriptions, rough sketchesOntologies

a data model that represents a set of concepts within a domain and the relationships between those concepts

UML a standardized specification language for object

modeling structure, behavior, and interaction diagrams really a specification language

The basic solution of/for a poor man 1

There are objects, and they are realisations of classes An example of a class: ”a wetland”

Classes have attributes and characteristics For exampe ”average depth” For example ”a wetland designed primarily for

birds”, ”a wetland for designed primarily for water quality improvement”

Classes have relationships For example ”a wetland is on a property”, ”a wetland

has a catchment”When some description is an attribute and when it is a relationship is a design choice

The basic solution of/for a poor man 2

There are processes For example ”a wetland is planned

and built and then it is in operation”

Ontologies (knowledge engineering)

Classes (concepts) a set of objects compare to an idea of an object a subset: subsume, inherit, ”is a kind of”

e.g. vehicle -> car

Attributes of classes name, value

Relationships between classes inheritance, ”a part of”, ...

Object-orientation (software development)

A program is a collection of cooperating objects cooperation is ideally based on

communication with messagesClasses, attributes, methodsInheritance, encapsulation, abstraction, polymorphismThe methods constitute the primary interface of an object, its data is encapsulated within the object. Methods may be inherited from superclasses and the behavior they awake may be different, giving raise to polymorphism.

XML (information system design)

A tree-like stucture of nodes each node has possibly a parent,

children, siblings (the siblings form a list)

a node consists of contents that is surrounded by begin and end tags, in the begin tag there may be named attributes with values

<tag attr1=”value”>contents</tag>