Geostatistics Workshop

Introduction

A workshop on geostatistics was presented in the Spring of 2000 at our Newtown Square office.  We had six attendees from other FIA units, one from our station, and two remote attendees via conference call and Netmeeting.  As promised, below is an attempt to make as much as possible from the workshop accessible on a webpage for you to access and refer to.  As we've worked on it, there have been revisions to the handouts which were distributed, the addition of more step-by-step detail and accompanying videos, and hopefully continued improvement to the general accessibility of the steps.  After a bit of intro I couldn't help including, (  :-)   ) contained in this page is a general flow chart of the process and an outline of the general steps.  These two hopefully provide a framework with which to work through the process.  Linked though out the outline are the step-by-step instructions, the videos, the software needed, illustrations from the powerpoint presentation, definitions and descriptions of different elements, example parameter files, guidelines, and additional discussion of some topics.  Not everything is complete, but this is hopefully a start.  We have tried to organize it so as to provide easy access to both the detailed info and the structure of the overall process.  As Andy has said before, take a look at it and let us know if this is at all useful to you.  If so, we will definitely endeavor to filling it in and incorporating any suggestions you have to make it more understandable and easier to use.

View: A Powerpoint Poster presenting a overview of Geostatistics

Objectives

• To create a continuous map/dataset of individual species distributions (or mortality, or removals, or growth...)
• With a measure of the uncertainty of the modeled estimates
• Containing some indication of the local variability that actually exists
• With an assessment of the accuracy of the output datasets
• With an understanding of how this map representation relates to what’s really on the ground.

Why?

• This translates the inventory data into a more easily available spatial context for analysis with other spatially referenced data (when they're not co-located)
• Together with the analysis that created it, it can give us a better understanding of the pattern and distribution of the resource
• Provides datasets which we can easily query to suit the individual management or research question at hand
• Provides information complementary to that gained by remote sensing

How to Use these Pages -- the links below take you straight to the section where each is described.  Most elements are also referred to and linked to from within other sections (e.g. the steps) as well. We recommend getting the videos and software, and then going through the flowchart and step by step. The navagation bar on the left provides access to these elements.
 

Comments

• Each species (or variable) behaves differently and will need to be assessed and its patterns investigated separately.  Some species may demonstrate more spatial structure and therefore be easier to model and estimate than others.  The complete dataset of species distributions, therefore, will contain a whole range of associated uncertainties
• What is truth and what is real?  We can get lots of  different images of reality from these models, each describing different features in the data and hopefully in the phenomena we are investigating.  What features are we most interested in representing in the final modeled dataset
• A task like this should always be undertaken by the people who know the sample data and the population and system it is trying to model.  Understanding why the data may be behaving a certain way, and trying to come up with the ‘ecological’ explanations (vs. the mathematical ones) for such observations in the data is a very important step toward understanding what you’ve got when you’re looking at the results

Next: Flow chart of General Process