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Finish up some XML

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images. Scale. XML for Science. Read-oriented access? perfect! Provenance ... georeferencing libraries... Geodesy: Elevation. Geodesy: Elevation. elliptical surface ... – PowerPoint PPT presentation

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Title: Finish up some XML


1
Topics
  • Finish up some XML
  • Class Survey
  • GIS
  • GRASS Demo
  • Raster vs. Vector
  • Spatial Databases
  • Multidimensional Indexes
  • Study Questions
  • Hand back Homework 1

2
XML for Science
  • Recall features of Science Data
  • Read-oriented access
  • Provenance
  • who, what, when, where, why
  • Interesting Data Types
  • timeseries
  • spatial
  • arrays
  • images
  • Scale

3
XML for Science
  • Read-oriented access?
  • perfect!
  • Provenance
  • requires some flexibility no problem
  • Interesting Data Types
  • and special file formats
  • Scale
  • could get ugly

4
Interesting Data Types
  • Data locked in binary file formats
  • Binary Format Description Language
  • Myers, Chappell 2000
  • Data Format Description Language
  • OpenGrid Project
  • Retrofitting Data Models
  • Howe, Maier SSDBM 2005
  • PADX
  • Fernandez et al, PLANX 2006
  • XDTM
  • Foster, Voeckler et al. Global Grid Forum 2005

5
XML Storage
  • Use RDBMS as your storage engine
  • Two approaches
  • Schema-aware
  • Schema-oblivious

6
XML Storage Schema-aware
DiningRoom(Manufacturer, Chairs, Quantity, Table)
Table(SKU, Wood, Type, Price)
Chair(SKU, Wood, Price)
7
XML Storage Schema-oblivious
Edge(NodeId, Tag, Value, ParentNodeId)
  • Remember fancy node-labeling schemes

8
Left/Right Labeling
0
34
4
5
10
1
2
3
6
9
7
8
Which queries are easy and fast? What did we say
the problems were?
9
Path Labeling
0
0.1
0.0
0.0.0
0.1.2
0.1.1
0.1.0
0.1.2.0
0.1.1.0
0.1.0.0
What queries are fast and/or easy? What did we
say the problems were?
10
Geographic Information Systems and Spatial
Databases
11
Represent This
source USA Today Weather
12
Represent This
source USA Today Weather
13
Represent This
Source www.mapsofworld.com/
14
Represent This
15
Represent This
16
Raster-Vector Data Model
Raster
Vector
Real World
17
Vector Data
  • The world is a collection of objects
  • Points
  • Lines
  • Polygons

18
Intermission Class Survey
19
GIS Geographic Information Systems
  • GIS is a collection of
  • file format converters and readers
  • algorithms (visibility, buffer, etc.)
  • visualization tools
  • georeferencing libraries

20
Geodesy Elevation
21
Geodesy Elevation
topographical surface
geoid
elliptical surface
22
Geodesy Map Projections
  • Cylindrical (Mercator)
  • Conical
  • Planar (Azimuthal)

transverse
secant
tangent
23
Map projection
http//www.geog.ucsb.edu/dylan/mtpe/geosphere/top
ics/map/map1.html
24
Spatial Databases
  • Spatial Database is an RDBMS equipped with
  • spatial types (points, lines, regions)
  • spatial functions (georeferencing, other
    algorithms)
  • multi-dimensional indices

25
Spatial Databases
  • Non-spatial queries
  • List all gas stations owned by Bob
  • List all unpaved streets
  • List galaxies with luminosity gt x
  • Spatial queries
  • List all gas stations with one mile of the river
  • List all gas stations touching an unpaved street
  • List galaxies within 2 arcmin of a quasar

26
Spatial Predicates
  • Each value has type Geometry
  • plus a subtype
  • point, line, polyline, polygon
  • Spatial Predicates
  • Geo Overlap(Geo, Geo)
  • bool Contains(Geo, Geo)
  • Geo Boundary(Geo)
  • bool Touches(Geo, Geo)
  • Geo Nearest(Geo, Geo)
  • Geo Nearest(Geo, Geo)

27
Multidimensional Indices
  • How do we answer topological questions
    efficiently?
  • B-Tree one dimension only

28
Multidimensional Indices
  • One way Impose a total order on the objects,
    then use an ordinary one-dimensional index
  • Ideas?

29
Space Filling Curves
  • How do we organize objects on disk so proximity
    is preserved?

30
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