New GPS Units for Data Collection

1
(No Transcript)
2
New GPS Units for Data Collection

• IPAQ Handheld PC with plugin GPS receivers
  (1000)
• 2-5 m accuracy
• ArcPad
• TDS Recon Handheld PC with plugin GPS (2000)
• 2-5 m accuracy
• Solo Field software (similar to ArcPad)
• Trimble GeoExplorer Handheld GPS receiver
  (4000)
• submeter accuracy
• Trimble software

3
Equipment Checkout

• 24 hours to 1 weekend only
• Project work for GEO 580
• Small thesis project work
• Contact Mark Meyers
• meyerss_at_geo.oregonstate.edu
• Terra Cognita Lab next door (Wilk 204)

4
Object-Orientation

• Longley et al., ch. 9
• Zeiler, chs. 4 and 5

5
Shapefiles and Topology

• discrete view
• separate, countable
• exhaust the space?
• space between objects?
• editing a polygon boundary?

6
ArcView Shapefile
7
ArcInfo Coverage
8
Topology

• adjacency, connectivity (defined in coverages)
• FNODE, TNODE
• LPOLY, RPOLY
• properties that are preserved under stretching of
  the space
• distinction between point, line, area is
  topological
• can't make a line into an area

9
Adding a New Polygon w/in a Coverage
10
Shapefiles

• Limited topology - 6 kinds of shapefiles
• Point
• Multipoint (several pts. represent one feature)
• polyline
• multipart polyline (segments disconnected)
• Polygon
• Multipart polygon
• Attributes in separate dBASE tables
• no topological info.

11
(No Transcript)
12
(No Transcript)
13
Object-Oriented Data Modeling

• Objects in the real world
• Natural rules and relationships
• Rivers flow downstream
• Roads handle levels of traffic
• Land parcels respect landuse laws
• How to build this intelligence into data
  structures?

14
OO Principles

• things in the world are instances of classes
• John Smith - human being
• Harrison Blvd. - street
• Corvallis - city
• Marys Peak - mountain (Hugh Grants hill??)
• Identity, Inheritance, Encapsulation

15
OO Principles ( cont. )Identity

• classes form hierarchies
• John Smith is an instance of the class male human
  beings
• male human beings are a subclass of human beings
• human beings are a subclass of mammals
• mammals are a subclass of fauna
• each subclass shares the properties of the class
• and may add special properties

16
OO Principles ( cont. )Identity

• geographic objects often group into complex
  objects
• an airport is composed of runways, hangars,
  terminals
• a state is composed of counties
• an area coverage is composed of polygons, arcs,
  nodes

17
OO Principles ( cont. )Inheritance

• Object can inherit properites
• old hierarchical database concept
• objects can inherit properties that are true of
  all objects of that type
• e.g., for all polygons
• new county in Oregon, still cant pump gas there
• and can also add new properties
• e.g., properties true only of a certain class
• rural county, always has diesel gas

18
(No Transcript)
19
OO Principles ( cont. )Encapsulation ( Behavior
)

• Object can encapsulate behavior (functions)
• what kinds of behavior?
• editing rules
• e.g, corners of a building must be square
• might apply to all buildings but not all polygons
• might apply only to some buildings
• two adjacent objects must have the same common
  boundary

20
Behavior ( cont. )

• attribute rules
• e.g., range of possible numbers
• dates in numerical format (only 1 to 12)
• split and merge rules
• 1 feature split or 2 features merged, what
  happens to attributes?
• e.g., split a street, the lengths of two parts
  are shares of the total
• e.g., merge two polygons, their population counts
  are summed for the combined polygon
• e.g., merge two polygons, their population
  densities are averaged, weighted by area

21
Example Merge Rule
22
Behavior ( cont. )

• editing, attribute, split and merge rules
• special procedures
• e.g., procedure to measure areas of polygons
• associated with polygon object type
• e.g., procedure to annotate contours
• specific interaction rules between objects
• e.g., a liquor store cannot be within 500 m of a
  school
• an offramp is required if a street and a freeway
  intersect
• at least one stream must flow out of every stream
  junction

23
A Smarter Data Model

• ArcInfo 7 coverage
• geometric information not stored in database
• ArcInfo 8 geodatabase
• stores geometric information as "shape" attribute
• closer to how we actually think about geographic
  features
• e.g., we don't naturally think about an area
  coverage as a collection of arcs
• Identity, Inheritance, Encapsulation (Behavior)

24
(No Transcript)
25
(No Transcript)
26
ArcHydro Feature Data Sets
27
ArcHydro Feature Classes
28
ArcHydro Feature Classes

• Hydrojunction
• Significant point locations in the hydro network
• Outlet of a watershed, the outlet of a lake or
  other water body
• Hydro Edge
• Flowlines are used to trace water movement
  through streams, rivers, and water bodies
• Shorelines form the interface between land and
  water for water bodies.

29
(No Transcript)