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Explore how spatial modeling addresses the complexities of big spatial data, offering solutions for managing large datasets, creating custom models, and running batch processes to meet diverse needs. Learn about Marine Spatial Planning, spatial data types, storage methods, modeling techniques, and software options for effective spatial analysis.
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Overview • What is “Big Data”? • What is Spatial Modeling? • Why do we care?
What’s the problem? • The issues we need to solve are: • Getting larger spatially • Involving more complex data • Involving more data • Require special algorithms • Require meeting the needs of and communicating with much larger groups of people
What’s the solution? • ArcGIS has limited ability to: • Manage complex datasets • Process large datasets • Create custom models • Run batch processes • Have to use ArcGIS appropriately, find other solutions to tough problems
Marine Spatial Planning • Over 100 raster layers • Millions of model runs • Years of work by teams of people • Multiple modeling packages • Maxent • Marxan • ArcGIS
Big Data • MODIS: • Entire earth at 250 meters resolution twice a day • Landsat: • Entire earth at 15/30 meters twice a month for 26 years • Human Genome • Global Biodiversity Information Facility (GBIF) • Climate models
Breaking it down • “Type” of spatial data: • Points • Polygon • Polyline • Rasters • Attributes/Measures: • Continuous, categorical measures • Dates • Descriptive text • Remotely sensed vs. Field data
How the data is stored • Large files (to be avoided) • Large sets of files • Relational databases • Distributed networks • Hierarchical storage
Spatial Modeling • Spatial Model: • Abstraction of something spatial • Typically on, or near, the earth’s surface • Spatial Processing: • Converting spatial data for a specific use • Spatial Analysis: • Analysis that uses spatial data • Spatial Simulation: • Models something that has or could occur spatially and temporally
Goals of Modeling • Verifiable against the real world • Robust; repeatable and insensitive to parameter variance • Transparent to modelers and stake holders • Simple to understand • Applicable to a real-world situation
Modeling Techniques • Interpolation: • Creates a raster with values for each pixel based on the proximity of sample points • Example: Climate layers from weather stations • Correlation: • Variable being predicted is dependent on other variables (N-dimensional space) • Habitat Suitability / Species Distributions • Others…
Interpolation • Kriging • Nearest-Neighbor • Bilinear • Bezier Surface • Delaunay Triangulation • Inverse Distance Weighting (IDW) • Natural Neighbor • Spline • Others…
Correlation or Dependence • Systems of differential equations • Common Statistical Functions • Kernel functions • Bayesian Inference • Regression • Index Models • Trees • Neural Nets • “Graphical” techniques • Combinations of the above
Non-Linear Correlation Several sets of (x, y) points, with the Pearson correlation coefficient of x and y for each set. Wikipedia
Others • Simple Representations • Cellular automaton • Agent-Based / Simulations
What is… • A shapefile of zip code regions? • A text file of points of bird observations? • The PRISM Data? • GoogleEarth? • Pika Model from Geo 565? • World of Warcraft?
Typical Spatial Models • Flood Planes • Potential Habitat/Species Distribution • Soil Erosion • Ice Extents • Climate Models • Oil Spill Extents • Bark Beetle Infestation • Geologic Layers • Flight Control Software
Model Characteristics • Stochastic or Deterministic • Transparent or “Black Box” • Simple or Complex • Rigorous or Lax • Applied or Theoretical • Internal or “External” Evaluation
Software • Correlation • ArcGIS • R (GLM, GAM…) • Maxent • HyperNiche (NPMR) • BlueSpray (HEMI) • ENVI/IDL • Marxan • WinBugs (Bayes) • BioClim • GARP • Open Modeler • Interpolation • ArcGIS • R • Others • Simple: ArcGIS • OpenSource? • Logo? • NetLogo? • Build your own! • Java • C++ • C#
More Detailed Process • Define the problem • Gather, process, and analyze the data • Investigate and select methods • Find, evaluate, and select the software • Build, parameterize, and run the models • Evaluate the model and results • Along the way, document: • Assumptions • Uncertainties • Problems others have seen
Occam’s Razor • “other things being equal, a simpler explanation is better than a more complex one”