The unique
qualities &
responsibilities of a
geographical
cyberinfrastructure
Mark Gahegan
Centre for eResearch &
Computer Science
University of Auckland
Overview
1. Data-intensive GIScience: from data poor to
drowning in 40 years
2. Challenges of organizing Big Data for GIScience
3. Challenges of computing with Big Data for
GIScience
Data poor to drowning
the case of remote sensing
Early remote sensing
platform
1980s: 30m x 30m pixels
2000s: 2.5 m x 2.5m pixels
Airborne Sensor platform
(much cheaper and more flexible than satellite)
One of the latest unmanned remote
sensing platforms
How much data so far?
• NASA’s Earth Observation System (EOS) program has
about 4.2 petabytes (2010)
– 430 times larger than the DT-LoC
– 3 times smaller than the output from the Large Hadron
Collider in a single year
• Similar sized collections can be expected in Europe
and Asia
• EOS contains mostly satellite data…not air photos,
map or field data
• What about ‘Volunteered’ data?
• And “The long tail of dark data…”?
How does that
compare to other
science disciplines?
• Large Hadron Collider
(Physics)
– 10-14TB year
– A 20km high stack of DVDs or
400,000 large PC disks
• Genomics (Biology)
– Imaging sequencers: Data
volume doubling every 6
months
– Can’t back it up to tape fast
enough
Big Data Challenges for CI
1. Storing unprecedented volumes of data (and accelerating)
– Data production passed storage capacity in 2007
– Cost differential is increasing, Rate of data production is increasing
2. Describing what we have in ways that are helpful to future users
(and our future selves)
– Metadata and Semantics for describing content (this tends to be producer-focused)
– But also use-case metadata and emergent relationships (tends to be consumer-focused)
3. Finding what we need, in the context of our current task
– semantically-enabled search engines that can use the above descriptions, (ideally from within
analytical tools and workflows)
4. Working out what we do not need to keep
– Because it will not be used again or offers no ‘information gain’
– Because it is easier to recreate than to store
5. Governing data collections well, within their communities of use
– information and knowledge portals
– effective governance of data resources
– quality control strategies, including peer review and rewarding excellent contributions
The Big Data responsibilities of CyberGIS
• Create successful tools and languages to describe
and find data, so that reuse is actively encouraged
• Enable the analysis,
• re-educate to reset the expectations…
• The data that we collect forms a natural history of
the changing planet on which we live
– The same cannot be said for many other sciences...
• This ongoing record is more important than the
individual research we each engage in
– Note we may not anticipate the questions that future
researchers may need to answer using our data
Emerging data opportunities…
What do these four different spatial analysis
tasks have in common?
• Find traffic bottlenecks…?
• Compute earthquake epicenters…?
• Track Influenza epidemics…?
• Perform land cover classification…?
‘Fourth paradigm’
–science led from
Big Data
HPC Analysis challenges of massive
data in Earth Science
Re-express (spatial) analysis algorithms so that
they scale across HPC hardware AND Big Data:
– Geometry: Point / line / region / volume—algebra,
selection, transformation, projection
– Topology: connectivity, route-finding, friction
– (Spatial) statistics: classification, interpolation
– Point pattern analysis / discovery: cluster detection
The challenge is to be SYSTEMATIC, not
piecemeal
What’s limiting the task?
• Memory?
– 1TB on a single compute node now
– 2-8TB on some equipment (e.g. SGI UV)
• CPU?
– Tightly bound—needs a lot of inter-process communication
– Embarrassingly parallel—can be perfectly decomposed
• Data?
– Random? Linear? Blocky? (Degree of locality of reference)
– Replication?
• Communications?
– Data channels, infiniband, metadata
• Nothing?
– Not everything needs to be parallelized…just the limiting segments
Domain Decomposition
Architecture
examples
Use case
Scaling
Shared
memory:
(OpenMP)
Usually bound to a single
compute node. Requires code
rewrite…
Increase node core count /
memory
Distributed
memory:
(MPI)
Scaling beyond the compute
node
Requires major rewrite
Additional MPI fabric used to
pass messages between nodes
Adaptive:
(Cassandra/H
adoop/SOG)
Data-intensive, evolving,
decomposition not fully
understood at outset
More data bandwidth by
adaptively dividing up and
replicating the data
Massively
parallel:
(BlueGene /
GPU)
Very high degree of
parallelization
and power efficiency
Potentially scales to 1,000,000
processors
Or to put it another way…
• How do GISci algorithms map onto the well
understood supercomputing templates
– Dense Grids
– Sparse Grids
– Computational Fluid Dynamics
– N-Body interactions
– Monte Carlo
– Data Intensive
– etc...
(Are all our algorithms covered by these templates?)
Slowdown
Cost of reengineering vs.
slowdown for GIS algorithms
Utility
Cost of reengineering
Sticky CyberGIS
How to attract and keep the community
involved?
– Outreach & community engagement
– Compelling and appealing functionality
•
•
•
•
Data and method repositories
Workflows
Semantic interoperability
Killer Apps…
– Incentives to contribute
– Continuity
Computational
workflows embedded in
social media
,
• Scripts, workflows,
simulations, experimental
plans statistical models, ...
• Repeatable, reproducible,
comparable and reusable
• Sharing propagates
expertise and builds
reputation
• One can be ‘friends with
an experiment’ in a
science, social network
http://myexperiment.org
Semantically translating map data
SemDat Web Service:
http://semdat.bestgrid.org/semdat/
Killer App example from geosciences:
earthquake modelling
Seismicity (ANSS)
Paleoseismology
Local site effects
Geologic structure (USArray)
Faults
(USArray)
Rupture
dynamics
(SAFOD,
ANSS,
USArray)
Seismic
Hazard
Model
In S A R Im a g e o f th e
H e c to r M in e E a rth q u a k e
A s a te llite
g e n e ra te d
In te rfe ro m e tric
S yn th e tic R a d a r
(In S A R ) im a g e o f
th e 1 9 9 9 H e c to r
M in e e a rth q u a k e .
Stress
transfer
(InSAR,
PBO,
SAFOD)
(from Leinen, 2004)
S h o w s th e
d is p la c e m e n t fie ld
in th e d ire c tio n o f
ra d a r im a g in g
E a c h frin g e (e .g .,
fro m re d to re d )
c o rre s p o n d s to a
fe w c e n tim e te rs o f
d is p la c e m e n t.
Crustal motion (PBO)
Crustal deformation (InSAR) Seismic velocity (USArray)
GEON: Chaitan Baru, SDSC
Conclusions
• Big Data creates new ways of approaching GIScience: discovery-led
rather than theory-led
– Need to scale up our storage
– Useful data is the data that can be reused…
• Scalable GIScience methods are needed now
– Domain decomposition has always been the challenge for GIScience,
and is still.
– A systematic analysis of algorithm bottlenecks and amenability to
parallelization has been missing for 20 years
– Such an analysis is an ongoing task…as new parallel HPC and data
paradigms become possible
– Re-educate to reset expectations among researchers
• Use the best technologies and tools from other disciplines who
have made this leap, especially bio-informatics, computational
chemistry, high energy physics
Questions?
Fourth paradigm and data complexity
1.
2.
3.
4.
Experiment & Measurement
Analytical Theory
Numerical Simulations
Data Intensive Computing
Data fusion + data mining + synthesis/learning + explanation
http://research.microsoft.com/en-us/collaboration/fourthparadigm/
Utilizing massive data to discover
and explain
Is not as easy as you might think…
– Poor and sparse samples, surrogates, bias…
– As number of dimensions increases it becomes
increasingly difficult to add in any data point
without giving rise to some kind of statistically
significant ‘pattern’ or ‘cluster’
– And parametric distributions become unreliable
– It is very difficult to discover useful things that are
unknown by experts
We need to capture the meaning of
data, not just the data itself
 aligning heterogeneous definitions in content, schema
Era
Eon
Period
Series
GEOLOGIC AGE
ROCK TYPE
Volcanic
STANDARD DEFINITIONS
• data content: rock types, time scale, …
• data schema
from www.GEONgrid.org
OneGeology
interoperability portal
Data from different
countries can be
integrated, despite
using different
geologic categories
/legends
Complete connected neighborhood of a research
article or dataset (Alfred knowledge browser)
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