Transcript Data Structures and Data Models

Data Structures and Data
Models
GIS-101 (Class #4)
Summer Semester 2006
GIS Data Structures
• Raster Data
• Vector Data
Advantages of Raster Data
• Simple data structure
• Compatible with remotely sensed or
scanned data
• Simple spatial analysis procedures
• Good source of base map data
Disadvantages of Raster Data
• Requires greater storage space
• Pixels structure can make graphical output
less pleasing
• Projection transformations are more
difficult
• Topological relationships more difficult to
represent
Advantages of Vector Data
• Requires less storage space
• Topological relationships are readily
maintained
• Graphical output more closely resembles
hand-drawn maps
Disadvantages of Vector Data
• More complex data structure
• Not as compatible with remotely sensed
data
• Software and hardware are often more
expensive
• Some spatial analysis procedures can be
more difficult
GIS Data Models
Clarification
“Data Models” in this context refers to how the data
itself is organized and comprised
“Data Models” can also refer to broader GIS projects in
which, for example, wildlife habitat or other subjects are
“modeled”
Two Common Vector Data Models
• Spaghetti Data Model
• Topological Data Model