2 - Spatial data model Flashcards
1
Q
4 levels of abstraction
A
- Real World
- Data Model
- Data Structure
- File Structure
2
Q
Primary files
A
.shp ➔ main file
.dbf ➔ database file
.shx ➔ stores feature geometry
3
Q
Secondary files
A
.prj➔ stores projection/coordinate system metadata
.xml ➔ stores general shapefile metadata
.sbn ➔ optimises spatial queries
.sbx ➔ optimises data loading
.cpg ➔ optional text file describes encoding
4
Q
.shp
A
Shapefile file - main file
5
Q
.dbf
A
database table file
6
Q
.shx
A
Shape Index File
7
Q
.prj
A
Projection file
8
Q
.xml
A
Extensible Markup Language File
9
Q
.sbn
A
Spatial Index File (ESRI)
10
Q
.sbx
A
Spatial Index Auxiliary File (ESRI)
11
Q
.cpg
A
Code Page File
12
Q
Integer grid (whole numbers)
A
- Represent discrete data
- Roads, rivers, landcover
13
Q
Floating point grid (decimals)
A
- Represent continuous data
- elevation, rainfall
14
Q
Spatial resolution
A
The size of each individual pixel or grid.
The smallest discernible object in an image
15
Q
High SR
A
- small cell dimensions
- lots of details
- lots of cells (smaller area)
