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Midterm next Wednesday

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

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Midterm next Wednesday

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  1. Midterm next Wednesday

  2. 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

  3. 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

  4. Major concepts - cont. • Geodatabase • what it is, why it’s important • Topology, Spatial Analysis • what they are, why they are important, how they relate • Object orientation • Identity, inheritance, encapsulation • Data Sharing (barriers)

  5. Concepts of Data SharingLongley et al., Chapter 11

  6. NSDI ---> geodata.govGeospatial One-Stop ( GOS ) • 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 • Geospatial One-Stop • www.geodata.gov/

  7. NSDI ---> geodata.govGeospatial One-Stop ( GOS ) • 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 ofgeospatial data • See GEO 465/565 lecture #6 • dusk.geo.orst.edu/gis/lec06.html#nsdi

  8. 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

  9. Digital Line Graphs (DLGs) • vector topographic maps • 1:24,000, 1:100,000 ,1:10,000

  10. 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

  11. Govt Agency Data Formats • 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.

  12. National Data Sharing (cont.) • new high resolution commercial imagery • 1 m resolution • www.spaceimaging.com

  13. Barriers to Data Sharing (2) how to describe what you need • how to assess whether some data set fits the need?

  14. 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

  15. 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"

  16. 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.geodata.gov/ or geographynetwork.com • Regional and campus clearinghouses, • www.geo.oregonstate.edu/ucgis/datasoft.html • Google

  17. Finding Data • How to find geospatial data on the WWW • 10,000,000 servers worldwide and quickly rising • containing order 1x 1015 bytes of information • several servers contain more than 1 x 1012 bytes of geospatial information (terabytes) • WWW search engines • Google, Yahoo, Ask Jeeves, Hot Bot, AltaVista • send out “spiders” to find pages • find the most important words in pages • build a catalog of words • how many pages contain the word "map”?

  18. Finding Data (cont.) • most important metadata element is geographic location • find me some data about area x • only some areas have names • what if there's no name for the area you want? • only some hits on a name lead to geospatial data • search engines work on text, not GIS data sets

  19. Some Searching Solutions (1) Know whereto look for a particular type of data • ortho.mit.edu contains a lot of DOQ data for Massachusetts • Valley library has free DOQ data for Oregon • osulibrary.orst.edu/research/guides/maps/ maproom.htm • USGS geospatial data is at the Eros Data Center, edc.usgs.gov

  20. (1)Types of Data (cont.) • Microsoft's Terraserver contains DOQs and Russian imagery • www.terraserver.microsoft.com • >1 terabyte • millions of hits per day • EPA data, www.epa.gov • Corvallis ecoregion data at www.epa.gov/wed/pages/ecoregions/ ecoregions.htm • Again, only SAPs know this stuff ...

  21. Some Searching Solutions (cont.) (2) Go to a clearinghouse site • www.geodata.gov • Over 300 servers • Common metadata format, FGDC standard • must select (multiple) servers to search • Regional node of NSDI • Oregon Coastal Atlas, www.coastalatlas.net

  22. Some Searching (cont.) (2) Go to a clearinghouse site • many states have government-sponsored clearinghouses • Oregon Geospatial Data Clearinghouse • www.oregon.gov/DAS/EISPD/GEO/alphalist.shtml • Campus clearinghouses • www.geo.oregonstate.edu/ucgis/datasoft.html • ESRI-sponsored data sites • Geography Network, www.geographynetwork.com

  23. Some Searching Solutions (cont.) (3) Go to a digital library a digital library whose contents are searchable by geographic location • National Academy of Sciences report Distributed Geolibraries (1999) • using a map • using a placename directory • using coordinates • what have you got about there?

  24. Digital Libraries (cont.) • specify area of interest as a box on a map • or one of millions of placenames • how do I know that the library is likely to have what I want? • collection level metadata • a description of the contents of a collection

  25. Digital Libraries (cont.) • OSU’s Oregon Explorer • oregonexplorer.info • UCSB’s Alexandria Digital Library • www.alexandria.ucsb.edu • Part of California Digital Library • over 2,500,000 data sets

  26. Some Searching Solutions (cont.) (4) Issue-oriented site … http://www.ushmm.org/googleearth/ Download and use Darfur KML from course lecture page Who knows where Google will go with sites such as this?

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