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sptemExp (version 0.1.4)

Constrained Spatiotemporal Mixed Models for Exposure Estimation

Description

The approach of constrained spatiotemporal mixed models is to make reliable estimation of air pollutant concentrations at high spatiotemporal resolution (Li, L., Zhang, J., Meng, X., Fang, Y., Ge, Y., Wang, J., Wang, C., Wu, J., Kan, H. (2018) ; Li, L., Lurmann, F., Habre, R., Urman, R., Rappaport, E., Ritz, B., Chen, J., Gilliland, F., Wu, J., (2017) ). This package is an extensive tool for this modeling approach with support of block Kriging (Goovaerts, P. (1997) ) and uses the PM2.5 modeling as examples. It provides the following functionality: (1) Extraction of covariates from the satellite images such as GeoTiff and NC4 raster; (2) Generation of temporal basis functions to simulate the seasonal trends in the study regions; (3) Generation of the regional monthly or yearly means of air pollutant concentration; (4) Generation of Thiessen polygons and spatial effect modeling; (5) Ensemble modeling for spatiotemporal mixed models, supporting multi-core parallel computing; (6) Integrated predictions with or without weights of the model's performance, supporting multi-core parallel computing; (7) Constrained optimization to interpolate the missing values; (8) Generation of the grid surfaces of air pollutant concentration estimates at high resolution; (9) Block Kriging for regional mean estimation at multiple scales.

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Version

Install

install.packages('sptemExp')

Monthly Downloads

5

Version

0.1.4

License

GPL

Maintainer

Lianfa Li

Last Published

July 7th, 2019

Functions in sptemExp (0.1.4)

countylayer

County layer map for illustration of block Kriging.
colorGrinf

Generation of Customed Gradient Colors
colorCusGrinf

Customed Color Generation by the Number of the Levels
GetARegionBK

Get a Regional Kriging
allPre500

The dataset of the prediction result for some days for 2014 Shandong, interpolated by constrained optimization.
conOpt

Function of Constrained Optimization
abatchModel

A Batch Modeing Training Inner Functions
exClusterByKruskal

Function of Kruskal Clustering with Spatial Distances
bnd

BND spatial topology data for use in spatial effect modeling.
bKriging

Regional Mean Estimation by Block Kriging
exeCluster

Efficient Clustering Using Union-Find to Obtain the Clusters for Each Sample
exeCluster1D

Efficient Clustering Using Union-Find to Obtain the Clusters for Each Sample
getRidbytpoly

getRidbytpoly for Assignment of Thiessen polygon id to point object
getPolyMMean

Generation of Regional Monthly Mean Based on the Input Polygons
extractVNC4

Extract Values for Point from NC4 Image
gtifRst

The 2014 time series of PM2.5 concentrations of Shandong province, with many missing values.
rSquared

Coefficient of Determination
inter2conOpt

Batch Interpolation of the Missing Values for Time Series Using Constrained Optimization.
extractVTIF

Extract GeoTiff Data
perMdPrediction

Batch Prediction Using the Trained Models
parSpModel

Generation of Spatiotemporal Models by Bootstrap Aggregating
noweiAvg

Averages over the Ensemble Predictions of Mixed Models (No weighted)
genRaster

Generation of Raster Covering the Side Map
samplepnt

Sample data for generation of Thiessen polygons.
parTemporalBImp

Function to Fill Missing Values by Constraint Optimization
voronoipolygons2

Generation of Thiesseon Polygons By Points
weiA2Ens

Ensemble Weighted Prediction of Mixed Models
rmse

RMSE function
parATimePredict

Batch Prediction for Time Series Using the Ensemble Models
fillNASVDSer

SVD to Interpolate the Missing Values in the Time Series Data
pol_season_trends

pol_season_trends .
fillNASVD

Function to Use SVD to Impute the Missing Values for Training Dataset
tpolygonsByBorder

tpolygonsByBorder for Generation of Thiessen polygons
trainsample

The dataset of 2014 training sample for the Shandong with missing values imputed using SVD.
prnside

Side to limit the Thiessen's polygons.
points2Raster

Generation of Grid Surface Using the predicted/Interpolated Values
getClusterCt

Retrieve the Central Coordinates for Each Cluser after Clustering Done.
shd140401pcovs

The dataset of 04/01/2014 prediction dataset for the raster spoint_pre covering the Shandong with 2km x 2km grid .
getTidBKMean

Batch Block Kriging for Estimate of Regional Means
shdSeries2014

The 2014 time series of PM2.5 concentrations of Shandong province, with missing approach.
getTBasisFun

Generation of Temporal Basis Function
weightedstat

Weighted Average for Multiple Models
spointspre

SpatialPointDataFrame as container of raster to geo-link with the specific date prediction of PM2.5.