Modeling Our World potx

[...]... geographic objects from the world MANY WAYS TO MODEL A SYSTEM Our interaction with objects in the world is diverse, and you can model them in many ways Consider one example, rivers Rivers are natural features, are used for transportation, delimit political or administrative areas, and are an important feature in the shape of a surface Here are a few of the many ways you can think about modeling rivers in a... model is best 2 • Modeling Our World Representations of geography features Features are discrete objects on a map Small objects are represented as points, long objects as lines, and broad objects as polygons surface network The earth’s surface can be kept in a geodatabase in several forms: as a triangulated irregular network (TIN), as elevation values on cells in a raster, or as contour lines A network... object-oriented data modeling to features Object-oriented data modeling lets you characterize features more naturally by letting you define your own types of objects, by defining topological, spatial, and general relationships, and by capturing how these objects interact with other objects Some of the benefits of the geodatabase data model are: • A uniform repository of geographic data All of your geographic... is your user interface to establish, modify, and refine the structure of your geodatabase The object view of data lets you focus your efforts on building a geographic data model and hides most of the physical database structure of the geodatabase Features in a geodatabase unified data model ArcInfo is versatile at displaying and analyzing geographic features ArcInfo works with a number of data sources,... Microsoft Jet is also installed; this provides the services for ArcInfo to create and update Access databases You do not need to separately install Microsoft Access 12 • Modeling Our World • You can deploy the relational database of your choice • You can serve geographic data from UNIX or Windows NT • You can serve data to other applications such as MapObjects®, ArcIMS™ (Arc Internet Map Server), ArcView®... environment The following is a simplified Unified Modeling Language (UML) diagram of a portion of the geodatabase data access objects This is discussed in chapter 4, “The structure of geographic data.” Domain Workspace Table FeatureDataset TinDataset RasterDataset RelationshipClass ObjectClass AttributedRelationshipClass Graph 0 1 GeometricNetwork 1 * 14 • Modeling Our World 1 * FeatureClass For many spatial... objects in the real world paths, settlements, and natural features The practice of cartography evolved to support diverse and inventive ways to characterize the many qualities of the real world Techniques were developed to depict classifications of features, identifying labels, the shape of the earth’s surface, and the flow of resources or goods Many of these practices are manifest in our modern maps,... policy An epidemiologist can correlate the locations of rare disease outbreaks with environmental factors to find possible causes Maps can integrate data from diverse sources into a common geographic reference A municipal 24 • Modeling Our World government can merge street maps with maps from utilities to coordinate construction An agricultural scientist can couple images from weather satellites with maps... elevation of features • The relative position among features Maps in a GIS also support spatial queries that create lists and selections 26 • Modeling Our World THE PARTS OF A MAP ArcInfo and its mapping application, ArcMap, present a model of a digital map that conforms to our experience with traditional maps You can print this digital map on a large-format printer to high cartographic standards You can interact... of the world s countries might have a number of attributes such as population, life expectancy, growth rate, and water quality However, geographic datasets do not contain the instructions for drawing the data You specify the methods for drawing data when you create a layer You can create multiple layers for the same dataset Each of these layers can depict a separate attribute 28 • Modeling Our World . 160 CHAPTER 10: SURFACE MODELING WITH TINS 161 Representing surfaces 162 Structure of a TIN 164 Modeling surface features 166 vi • Modeling Our World CHAPTER 11:. mimic the interactions and behaviors of real -world objects. 8 • Modeling Our World A geodatabase can contain four representations of geographic data: • Vector