Midterm next Wednesday

Midterm• May start off with multiple choice

• Bulk will be short answer/short essay

• Lecture PPTs and your notes, readings in Longley et al., Zeiler

• Will not include – Labs or Arc Marine exercise

– Journal articles

Major concepts

• Representations• Object vs Field• Model, data model, analysis model• Data models

– UML terminology, basic procedure from• Reality --> conceptual --> logical --> physical

– Customized Arc GIS data models• For enterprise GIS

• Analysis Models– Binary, ranking, rating, weighted rating

Major concepts - cont.

Concepts of Data SharingLongley et al., Chapter 11

NSDI ---> data.gov

• Who needs to share data? – jurisdictions with common borders

– jurisdictions in a region

– private and public sectors

– local, state, and Federal agencies

– government and individuals

NSDI ---> data.gov• State, local, private production of

geospatial data – loss of Federal monopoly, patchwork

– variable accuracy, level of detail

– the WWW

– everyone can be a producer, publisher, distributor of geospatial data

• See GEO 465/565 lecture #6– dusk.geo.orst.edu/gis/lec06.html#nsdi

Barriers to Data Sharing(1) interoperability

– will ArcGIS read Intergraph data?

– find a common format that both can read • output into the common format • input the common format

– is the common format the same as one of the GIS formats?

• if yes, only one conversion is needed • if no, two conversions are needed

– issues of format, syntax within ONE GIS

• Digital Line Graphs (DLGs)–vector topographic maps

–1:24,000, 1:100,000 ,1:10,000

Govt Agency Data Formats

• Digital Raster Graphics (DRGs)– raster topographic maps at

1:24,000

• Digital Elevation Models (DEMs)– raster elevation data

– 90m, 30m, 10m

– Oregon 10m DEMs from buccaneer.geo.orst.edu/dem

• Digital Orthophoto Quads (DOQs or DOQQs)– aerial photographs

– camera orientation, terrain info.

– raster images at 1m resolution

– 6m positional accuracy at scale of 1:12000

• Imagery– satellites

– Landsat, SPOT, SPIN, etc.

Govt Agency Data Formats

National Data Sharing (cont.)

• new high resolution commercial imagery • 1 m resolution• www.spaceimaging.com

Barriers to Data Sharing(2) how to describe what you need

– how to assess whether some data set fits the need?

Describing Data

• Metadata• Again, see GEO 465/565 lecture #6

– dusk.geo.orst.edu/gis/lec06.html#nsdi

• ArcCatalog– graphic thumbnail

– Tables

– FGDC format metadata

– ESRI format metadata

– XML format metadata

Issues with metadata?

• potential complexity– can be larger than the data set!

• investment to create– can be larger than the data set!

• carrots and sticks – FGDC’s "don't duck metadata"

Barriers to Data Sharing

(3) retrieval - large spatial data sets(4) national security - e.g., impact of 9/11(5) search engines

– how to know where to look on the WWW?– SAPs know where to look (more on this soon)

• National clearinghouse, www.data.gov• Regional and campus clearinghouses• www.geo.oregonstate.edu/ucgis/datasoft.html• Google