geospatial attribute data
DESCRIPTION
Geospatial Attribute Data. We Lied!. Earlier this semester we claimed that data was either spatial, i.e. said where something was, or attribute, i.e. told you something about an object. In fact, on the exam, we accepted “non-spatial data” as part of the definition of attributed data. - PowerPoint PPT PresentationTRANSCRIPT
CS 128/ES 228 - Lecture 10b 1
Geospatial Attribute Data
CS 128/ES 228 - Lecture 10b 2
We Lied!
Earlier this semester we claimed that data was either spatial, i.e. said where something was, or attribute, i.e. told you something about an object.
In fact, on the exam, we accepted “non-spatial data” as part of the definition of attributed data.
BUT, it’s not that simple…
CS 128/ES 228 - Lecture 10b 3
Some attribute data is tied to a location, not an object
Estimate of phytoplankton distribution in the surface ocean: global composite image of surface chlorophyll a concentration (mg m-3) estimated from SeaWiFS data (Source: NASA Goddard Space Flight Center, Maryland, USA and ORBIMAGE, Virginia, USA).
Estimate of phytoplankton distribution in the surface ocean: global composite image of surface chlorophyll a concentration (mg m-3)
estimated from SeaWiFS data (Source: NASA Goddard Space Flight Center, Maryland, USA and ORBIMAGE, Virginia, USA).
CS 128/ES 228 - Lecture 10b 4
Spatial Data – A Few Definitions Spatial data: Data that have some form of spatial or
geographical reference that enables them to be located in two or three-dimensional space. -- Heywood, Cornelius & Carver, p. 289
Spatial data: Data that relate to the geometry of spatial features. -- Chang, Introduction to Geographical Information Systems, p. 4
Spatial data: Any information about the location and shape of, and relationships among, geographic features. This includes remotely sensed data as well as map data. -- The GIS Dictionary, http://www.geo.ed.ac.uk/agidict/welcome.html, searched 3/27/2007
CS 128/ES 228 - Lecture 10b 5
A Compromise
Geospatial Attribute Data
Data about a non-spatial entity that is intrinsically tied to a given
location
CS 128/ES 228 - Lecture 10b 6
Examples of Geospatial Attribute Data
• Rainfall
• Snow depth
• Land use
• Crime rates
• Average income level
• Population statistics
CS 128/ES 228 - Lecture 10b 7
What is special about this data?
Data sets are generally very large
Turning such data into information (or knowledge) can be tricky (or worse!)
Dimensionality becomes an issue
CS 128/ES 228 - Lecture 10b 8
Dimensionality Paper maps are
generally two-dimensional
While color can be used as a third dimension, it is more often used for attribute display
CS 128/ES 228 - Lecture 10b 9
Sometimes 2-D works
Source: U.S. Census Bureau, 2005 American Community Survey (American FactFinder)
CS 128/ES 228 - Lecture 10b 10
More fine-grained 2-D
Image from: http://www.csc.noaa.gov/products/nchaz/htm/lidtut.htm
CS 128/ES 228 - Lecture 10b 11
What’s the Weather Like in Merry Old England? Source
CS 128/ES 228 - Lecture 10b 12
When 2-D tends to work
“Planar” area being mapped
One piece of data for each position
Minimal problem locating data in “space”
No “time” dimension
CS 128/ES 228 - Lecture 10b 13
What about Time?
Traditionally described as a “fourth” dimension, time adds a “third” dimension to GIS data.
This creates problems converting the data to information and knowledge.
2-D maps usually don’t cut it.
CS 128/ES 228 - Lecture 10b 14
Solutions to the “Time Dilemma”:1. Graphs
Source:
National Weather Service
http://newweb.erh.noaa.gov/ahps2/hydrograph.php?wfo=buf&gage=olnn6&view=1,1,1,1,1,1
CS 128/ES 228 - Lecture 10b 15
More graphing
http://www.pmel.noaa.gov/tao/disdel/disdel.html
Tropical Ocean Array
•Buoys in Pacific Ocean
•Monitor Conditions
•Monitor El Niňo
CS 128/ES 228 - Lecture 10b 16
Custom Graphs from TOA Monthly Wind
Speed data for the buoy I selected
1977-2007
CS 128/ES 228 - Lecture 10b 17
Also available as… Downloadable data file
Formatting can be an issue But if you add it you your GIS, it’s yours!
Location: 8S 165E 16 Aug 1991 to 16 Mar 2007 ( 188 times, 2 blocks) Gen. Date Mar 28 2007 Units: Winds (M/S), W. Dir (DEG), -99.9 = missing, (1,1) is NE at sqrt(2) m/s Time: 1200 16 Aug 1991 to 1200 16 Aug 1996 (index 1 to 61, 61 times) Depth (M): -4 -4 -4 -4 QUALITY YYYYMMDD HHMM UWND VWND WSPD WDIR SD 19910816 1200 -5.0 0.7 5.6 278.1 22 19910916 1200 -2.9 -1.4 4.8 243.7 22 19911016 1200 -2.7 -0.1 3.4 268.2 22 19911116 1200 -0.2 2.1 4.3 354.3 22 19911216 1200 -0.5 1.7 3.3 344.0 22 19920116 1200 1.8 1.3 4.2 53.8 22 19920215 1200 4.4 0.3 5.3 86.2 22 19920316 1200 4.0 1.0 5.3 75.7 22
CS 128/ES 228 - Lecture 10b 18
Solutions to the “Time Dilemma”:2. Multiple Images Really just a set of 2-D images shown side-by-
side or in sequence
Source:http://commons.wikimedia.org/wiki/Image:ElectoralCollegeYYYY-Large.png
CS 128/ES 228 - Lecture 10b 19
Items of note
• Each of the images here is a separate map, no longer associated with a GIS
• Each map actually contains summary information as well as traditional map elements
CS 128/ES 228 - Lecture 10b 20
Solutions to the “Time Dilemma”:3. Animation
http://encarta.msn.com/encyclopedia_761567360_1/Animation.html
Animation: motion pictures created by recording a series of still images—drawings, objects, or people in various positions of incremental movement—that when played back no longer appear individually as static images but combine to produce the illusion of unbroken motion.
CS 128/ES 228 - Lecture 10b 21
My Daily Habit – Doppler Data
Animation
CS 128/ES 228 - Lecture 10b 22
More Weather From England
http://www.xcweather.co.uk/
CS 128/ES 228 - Lecture 10b 23
Watch My Friends Ride Across The Country
http://stats.raceacrossamerica.org/2006/animation/
A similar site, with elevation profiles, exists for the Tour de France, but it only animates during the race
CS 128/ES 228 - Lecture 10b 24
Get Seasick?
http://www.pmel.noaa.gov/tao/jsdisplay/
CS 128/ES 228 - Lecture 10b 25
What if there is a real third dimension?
Actual images (video) But these can only show “transparent” or
“discrete” attribute data Flyovers/fly-throughs help
Virtual reality But most users don’t have the equipment
to “view” this
CS 128/ES 228 - Lecture 10b 26
And in the movies…
(Screen snapshot of) Animation of tornado-monitoring “buoys”
from the Warner Brothers film Twister
Source: http://www.vfxhq.com/1996/twister.html
CS 128/ES 228 - Lecture 10b 27
Conclusions about geospatial data
• It’s abundant
• It’s important
• Display is a challenge
• Technologies only get better
CS 128/ES 228 - Lecture 10b 28
Great Data Sets Abound
• Census bureau
• USGS
• Weather Service
• Scientific labs
(esp. government funded)