We all want to know the future, but what is the best way to predict what will happen? Assuming we don’t have a crystal ball or a time machine, we have to find patterns in the available information and use that make our best, informed guess. This is what scientists do. There is a spectrum …Continue reading “Oracles and Science: The Trouble with Predictions”
Proponents of digital soil mapping sometimes criticize traditional soil mapping for using a discrete data model to describe a continuous surface (field) and lacking a quantified estimation of error. Although most of my research is on digital soil mapping, I like to give due credit to the accomplishments of traditional soil mapping. I understand the need for …Continue reading “The Real Benefits of Digital Soil Mapping”
We always want to avoid error, but it is a fact of life. At the foundation of analysis and modelling, we rely on measurements. Because errors in measurements are inescapable, the important question is how much does the error affect the result? I start the conversation by explaining what measurement error is, including its component parts, and what we can do to minimize its effect.
From as early as 500 BCE, humans have recognized that some things vary together in space. This is essentially correlation, but the spatial aspect sometimes adds a special twist. Also, correlation requires evaluation of quantitative data, while this concept is not limited to quantitative characteristics. For example, Diophanes of Bithynia observed that “you can judge …Continue reading “CLORPT: Spatial Association in Soil Geography”
Soil scientists like to remind everyone that “soil is not dirt.” They are of course, right, but what is the difference? I would argue that an important distinction is a question of where. Is it somewhere that it is useful, fulfilling its role as supporting life and improving environmental quality? Or has it been moved …Continue reading “The Value of Soil: A Spatial Perspective”
UPDATE: The tremendous response to this blog post led to an international and interdisciplinary survey on how these terms are/should be defined. The results of that survey were combined with an in-depth review of the literature to produce an article that has now been published in Earth-Science Reviews. The article updates and refines the patterns …Continue reading “Colluvium vs Alluvium”
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 …Continue reading “Accuracy vs Precision”
When you read the phrases “large scale” or “small scale,” do you know what they mean? Sometimes “large scale” describes a large area, and sometimes it describes a small area, depending on if the author was thinking about process scale or cartographic scale. This is a problem for communication. In this post, I will describe …Continue reading “Types of Scale”
In the process of creating a map, geographers often have to engage in the activity of spatial prediction. Although there are many tools we use to accomplish this task, they generally boil down to the use of one or two fundamental concepts. Waldo Tobler is credited for identifying the ‘first law of geography’, stating “Everything …Continue reading “Fundamentals of Spatial Prediction”
In an earlier post I contrasted induction and deduction while suggesting that induction is the currently favored term used in science. However, I also suggested that the two philosophies can be used in concert with one another. Indeed, as much as one can argue about the virtues of one philosophy or the other, science actually advances …Continue reading “The Cycle of Science”
