GI Science spatial data modelling Dr Nigel Trodd Science and the Environment Coventry University

Aim & objectives To understand the process of building a digital representation of reality to characterise reality (as a spatial concept) to identify the process of modelling geographical phenomena to identify & exemplify entitation & data modelling to identify vector and raster data & their data structures

Building GI models I am a Geographer I model places & spatial phenomena I am a Computer Scientist I model information in a database GI Science = Geography + Computer Science

How can we store geographical data in a computer?

the real world is complex and computers are very simple and computers need us to model the geography for them.

How do we model the real world in a computing environment ? from reality to spatial data structures in (easy) steps

1. from reality to geographical phenomena 2. from geographical phenomena to spatial entities 3. from spatial entities to spatial data models 4. from spatial data models to spatial data structures 1. from reality to geographical phenomena 2. from geographical phenomena to spatial entities 3. from spatial entities to spatial data models 4. from spatial data models to spatial data structures

terminology overload there’s more

How do we view reality? 1. from reality to geographical phenomena Values at different places Continuous variation – biomass, elevation, SST Points and edges with associated data Discrete objects - house, pipeline, river, coastline

1. from reality to geographical phenomena 2. from geographical phenomena to spatial entities the famous 5ive... points lines areas networks & surfaces

4Geometry 4Topology 4Concepts of geography 3. from spatial entities to spatial data models object-based field (or layer) -based

wakey … here comes the easy bit

vector & raster

4. from spatial data models to spatial data structures

I am NOT a Geographer I am NOT a Computing Scientist I am a GI Scientist. I model. I am crude. I use basic IT. I work. Summary

I am a GI Scientist. Are you? outline the art of building a digital representation of reality. identify & exemplify 5 spatial entity types. explain the elements of a spatial data model. identify differences between vector and raster data & exemplify their data structures.