SpatialVx

Eric Gilleland Weather Systems Assessment Program

Research Applications Laboratory

2016 MesoVICT Workshop Wednesday, 21 September 2016

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SpatialVx

http://www.ral.ucar.edu/projects/icp/SpatialVx/ http://www.r-project.org

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SpatialVx

Name Description Functions Notes Tested Field Significane

Simulation-based field significance testing

spatbiasFS, LocSig,MCdof

Contributed by Kim Elmore

?

Spatial Prediction Comparison Test (SPCT)

Hypothesis test (CI’s) for competing forecasts that accounts for spatial dependence

spctlossdiffempiricalVG.lossdiffflossdiffsummary

Assistance from Amanda Hering

Yes

Significance Testing

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SpatialVx Significance Testing

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SpatialVx

Name Description Functions Notes Tested Fractions Skill Score (FSS)

Compares event frequencies within neighborhoods

hoods2d Makes use of fft from R package stats.

Yes

Most other neighborhood methods

see Ebert (2008, Meteorol. Appl., 15, 51 - 64. DOI: 10.1002/met.25)

hoods2dpphindcast2dupscale2d

Some

Wavelet de-noising Smoothing by way of wavelet denoising

wavePurifyVx Uses waveslim package by Brandon Whitcher

Yes

Low-pass Filtering / Neighborhood Methods

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SpatialVx

Name Description Functions Notes Tested Intensity Scale (IS), Wavelet Details

Summary measures of wavelet detail fields

waveISwaverify2d

Uses waveslim package

Some

Structure Function Variability/structure at different spatial lags

structurogramstructurogram.matrixvariogram.matrix

Heavy copying of vgram.matrix from fields package by Doug Nychka et al.

Some

Band-pass Filtering / Scale Separation

Very good, recent review paper about wavelet spatial verification methods (+ a new proposed technique): Weniger, M., F. Kapp, and P. Friederichs, 2016: Spatial Verification Using Wavelet Transforms: A Review. arXiv preprint arXiv:1605.03395

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SpatialVx

Name Description Functions Notes Tested Binary Image Metrics

Distance map based summary measures

locmeasures2dlocperf

Uses distmap, deltametric, and other functions from R package spatstat.

Some

Forecast Quality Index (FQI)

Image metric that accounts for intensity differences as well as displacmeents

FQI No

Displacement measures

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SpatialVx

Name Description Functions Notes Tested Zhu’s metric linear combination of

two measures: (i) the amount of overlap between events in two fields and (ii) the mean error distance

metrV Yes

Image Moments Summary information for an object or field, e.g. centroid, orientation angle, etc.

imomenter Yes

Displacement measures (continued)

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SpatialVx

Name Description Functions Notes Tested Optical Flow (OF) Deform forecast

using gradients OF Contributed

by Caren Marzban

No

Rigid transformation

Deform forecast using translations and/or rotations only

rigiderrigidTransform

Needs more

Field Displacement

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SpatialVx Name Functions Notes Tested Identify Features FeatureFinder Uses

connected function from R package spatstat

Yes

Merge/Match Features

centmatchminboundmatchdeltammMergeForce

Some

Analyzing Features

FeatureMatchAnalyzerFeatureAxisFeaturePropsFeatureCompsFeatureTable

Some

Feature-based

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SpatialVx Name Description Functions Notes Tested Cluster Analysis Use statistical

cluster analysis to define features

clustererCSIsamples

CSIsamples contributed by Caren Marzban

Some and ?

Contiguous Rain Area (CRA)

Use rigid transformation and breakdown RMSE

craer No

Structure Amplitude Location (SAL)

Distributional comparisons of identified features

saller Some

Composite Distributions of features

compositer No

Shape Analysis Reduce features to landmark points describing their shape

hiwdistillsummary

Obtains landmarks (tricky) for use with shapes package

Yes, but …

Feature-based (cont.)

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SpatialVx Feature-based

X (feature 1) Xhat (feature 1)

Observed Feature

Forecast Feature

Shape Analysis

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SpatialVx

Name Description Functions Notes Tested Method for Object-based Diagnostic Evaluation (MODE)

MODE-type analysis interester Minimal

Feature-based (cont.)

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Name Description Functions Notes Tested Geometric Indices

Summarizes shapes and texture within a field

Cindex, Sindex and Aindex

Yes

SpatialVx

Field Patterns / Texture

Aindex and Sindex useful for single objects too. See also variogram and variogram.matrix for analyzing field texture. New wavelet method, but not in SpatialVx (so far!)

AghaKouchak et al. (2011, doi:10.1175/2010JHM1298.1)

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SpatialVx Name Description Functions Notes Tested Anomaly Correlation Coefficient

Correlation using a climatology instead of the mean

ACC Some

Bias-adjusted Gilbert Skill Score

Accounts for spatial bias

vxstats Some

Gaussian Mixture Models (GMM)

Fitted parameters inform about displacement errors

gmm2d Very Slow

Yes

Geographic box plot

Box plots that account for grid box area differences

GeoBoxPlot Yes

S1 score Comparison of gradients between two fields

S1 No

Miscellaneous

New User’s Group

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https://www.linkedin.com/groups/8550343

Future Plans •  Finish/Start Testing all functions •  Get all functions in-line with general

methods for functions •  Methods Needing to be Added

§  Image Warping § Optical Flow/DAS (Keil and Craig) § Newly Proposed Methods § New modifications of FSS § Other?

•  Write a tutorial

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Questions?

Thank you to those who have been testing functions from the package. It is nice to have the help! It is always appreciated to have bugs and other errors identified

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