Vector Data Flashcards
True or false: vector data is always lines,points or polygons.
True
What is resolution equivalent to in vector data
Resolution here is determined by the level of precision and accuracy with which spatial features are represented
Difference between raster and vector data.
Check post it
Hy is it important to ensure that data sets are correct ?
This is because there can be topological errors that can cause mistakes
What is topology ?
This refers to the spatial relationship between geographical features. This defines how features are related in terms of adjacency, containment and connectivity etc.
Why is topological relationship important
It is essential for maintaining data accuracy and integrity
How does a polygon number look ?
It is always circled
What does a line number look like ?
It is never circled
What are some of the topological characteristics
Defines connections and relationships between objects.
All lines must connect, all polygons closed and loose ends removed.
All space on the map must be filled.
Searching is much quicker.
Not necessary for visualization process.
True or false these terms are related to topology: node,junction,segment,polygon,vertex,line
True
What are the different scales at which attributes are measured?
Nominal scale: just labels and names without order (eg. Type of land use)
Ordinal scale : ordered categories with constant differences between them ( ranking objects according to size).
Interval scale : ordered categories with equal intervals and no true zero point.(height above sea level).
Ratio scale: ordered categories with equal intervals and a true zero point ( distance measurement).
Cyclic scale : data just repeats itself (months of the year)
Nb: complexity increases as you go down .
W
Differences between TIN and gride
revise that :lecture 2 slide 19.
