2015-03 Uncertainty Evaluation of Computer Simulation Models (Draft Report)

Deterministic agricultural and agro-ecosystem systems models have an important role worldwide. Although these models are mathematically deterministic, there are many possible sources of uncertainty that can propagate through the model. The development of tools to evaluate uncertainty in deterministic models is an active area of research. There are a number of options for model uncertainty evaluation that have been discussed in the literature. The objectives of this review paper are threefold: 1. To describe a formalised state-space framework within which to describe the types and sources of uncertainty that arise in computer simulation models. 2. To provide a framework to carry out a robust uncertainty evaluation of a computer simulation model. 3. To summarise a selection of relevant sampling and analysis techniques for the uncertainty evaluation of computer simulation models.

Esther Meenken, Chris Triggs et al.

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2015-02 New Zealand’s Climate Data in R – An Introduction to clifro

The National Climate Database contains data collected from around
6,500 weather stations throughout New Zealand, providing a necessary
repository for any study involving New Zealand’s weather or climate.
Although data from this database can be accessed via a web portal (CliFlo),
the vast amount of information is not readily consumable. The clifro
R package provides the necessary functions to easily integrate the
National Climate Database with R, and provides a variety of elegant plotting
methods for data exploration. Also, by supplying functions to access the
database via CliFlo programmatically, clifro allows for transparent and
reproducible research when using these data.

Blake M. Seers and Nick T. Shears

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2015-01 Introducing OpenAPI

The OpenAPI project attempts to make it easier to connect people with data. This document discusses some of the challenges faced in connecting people with data, and how OpenAPI addresses these challenges. It describes the technical specifications of the OpenAPI architecture, and provides some examples of OpenAPI in action. This document also discusses projects similar to OpenAPI, and how OpenAPI is distinct from these.

Ashley Noel Hinton and Paul Murrell

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2014-03 The gridGraphics Package

The gridGraphics package provides a function, grid.echo(), that can be used to convert a plot drawn with the graphics package to the same result drawn using grid. This provides access to a variety of grid tools for making customisations and additions to the plot that are not possible with the graphics package.

Paul Murrell

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2014-02 Invertible Reproducible Documents

Reproducible documents provide an efficient way to produce reports by automatically generating content from code chunks within the report. The processing of a source document, that contains code chunks, to a final document, that contains automatically-generated content, is typically one way, with the resulting report being read-only. This report describes an experiment that attempts to make the final report document modifiable and attempts to invert the process from final document back to source document so that the modifications to the final document can be efficiently conveyed back to the original author of the report.

Eric Lim, Paul Murrell, and Finlay Thompson

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2014-01 Improving the ‘gridGraphviz’ package in R

The gridGraphviz package renders node-and-edge graphs in R using the grid graphics package. Graphs are laid out using the Rgraphviz package to interface with the graph layout algorithms in graphviz. This article details the improvements made between gridGraphviz versions 0.2 and 0.3, including: support for “ellipse”- and “polygon”-shaped nodes; handling of edges in undirected graphs; support for various new arrow types; and support for edge labels. Version 0.3 also introduces a method to produce graphs with an overall size closer to graphviz’s output.

Ashley Noel Hinton and Paul Murrell

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2013-10 Automatic Conversion of Tables to LongForm Dataframes

TableToLongForm automatically converts hierarchical Tables
intended for a human reader into a simple LongForm Dataframe that is
machine readable, hence enabling much greater utilisation of the data.
It does this by recognising positional cues present in the hierarchical
Table (which would normally be interpreted visually by the human brain)
to decompose, then reconstruct the data into a LongForm Dataframe. The
article motivates the benefit of such a conversion with an example
Table, followed by a short user manual, which includes a comparison
between the simple one argument call to TableToLongForm, with code for
an equivalent manual conversion. The article then explores the types of
Tables the package can convert by providing a gallery of all recognised
patterns. It finishes with a discussion of available diagnostic methods
and future work.

Jimmy Oh

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2013-9 Improved Importing of Vector Graphics in R

The grImport2 package imports vector images that are stored in the SVG image format for inclusion within images generated by R. The original grImport package performs the same task, but instead using PostScript images as its source image format. This technical report describes the steps taken to improve not only the grImport package, but also follows the development of two new packages, grImport2 and grConvert. The latter, grConvert, converts images from popular vector image formats (PostScript, PDF and SVG) into valid input formats for grImport and grImport2. The grImport2 package is an entirely new package that does not suffer from some limitations of the grImport package, whose limitations are primarily due to the dependence on the PostScript image format.

Simon Potter and Paul Murrell

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2013-8 Selection and Navigation of Overlapping SVG Objects

SVG is a vector graphic image format that can be used with
browsers to deploy dynamic, interactive graphics over the web. We
present a method that enables generalised Selection and Navigation of
Overlapping SVG Objects by toggling pointer-events CSS styles and the
use of the mousewheel, adding another tool developers can use to grant
users greater and more intuitive interaction with SVG images. We also
present several live examples that demonstrate the method in practice,
both on script generated SVG images and an externally generated SVG image

Jimmy Oh

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2013-7 Advanced SVG Graphics from R

The gridSVG package has recently provided an interface for
some more advanced SVG graphics features: gradient fills and pattern
fills, clipping paths, masks, and filters. This report describes a
simple test case for some of these advanced graphics features and then
explores some ideas for making use of these features in Statistical
Graphics.

Paul Murrell and Simon Potter

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