• Error Propagation Toolbox

    error propagation

    New estimated errors are calculated for each raster cell based on the combination of the two input rasters.

    Quantifying uncertainty can be a very useful and often important aspect of evaluating results of calculations, particularly in modelling. The same applies for spatial layer mashups where the grids provide the input variables for equations that are calculated spatially (i.e. raster calculator). This toolbox for ArcGIS uses standard error propagation equations to simultaneously calculate the result of basic math expressions along with the estimated error of that result. The measured or estimated errors for the input variables are required. Error covariances can also be included in the calculation of error propagation, but are not required.

    Download the Error Propagation Toolbox (178.6 KB)

     

     

  • Particle Size Analysis Toolpack v2

    A zip file containing a suite of tools for analyzing continuous particle size curves from laser diffractometry.

    Includes:

    • export templates for Malvern software,
    • analysis template for recommended quality control procedure,
    • reporting templates for organized presentation of results with additional metrics, and
    • a data filter for removing the larger particle size peak from bimodal curves.

     

    Download the PSA Toolpack (4.7 MB)
  • Accuracy vs Precision

    Scientists often measure and predict things. Therefore, we need ways to describe how much we know, how close a number is to reality, and how likely we are to get the same number again. The terms accuracy and precision are generally used to describe these things, but there can be some ambiguity. This post explains the difference between the two and explores the different aspects of precision’s multiple meanings.

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  • Late-Pleistocene paleowinds and aeolian sand mobilization in north-central Lower Michigan

    Simulation of late glacial atmospheric conditions with atmospheric general circulation models suggest a strong anticyclone over the Laurentide Ice Sheet and associated easterly winds along the glacial margin. In the upper Midwest of North America, evidence supporting this modeled air flow exists in the orientation of paleospits in northeastern Lower Michigan that formed ∼13 ka in association with glacial Lake Algonquin. Conversely, parabolic dunes that developed between 15 and 10 ka in central Wisconsin, northwestern Indiana, and northwestern Ohio resulted from westerly winds, suggesting that the wind gradient was indeed tight.

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