An Introduction to Scientific Research Methods in Geography
Montello and Sutton
Chapter 4 - Physical Measurements
Basic tools and techniques for collecting physical measurements
in both physical and human geography.
Learning Objectives
-What are physical models and how are they used in geography?
-What are representative types of physical measurements made by
geographers and other scientists who study the four earth systems of the
lithosphere, atmosphere, hydrosphere, and biosphere?
- What is geodetic measurement and what are some types?
- What are nonreactive measurements in human geographic research?
- What are the three actions of accretion, deletion, and modification that
create physical traces of human activity, and what are the four types of
functions of physical traces?
Physical Measurements in Physical Geography
- Before taking any field measurements you must first consider field
research logistics. Accessibility, legality, equipment transportation to
and from the site (can you bring plant matter through customs?),
contingency plans for medical emergencies….
- Physical models: physical or material simulation of a portion of
reality.This allows geographers to take measurements removed from the
field and with a degree of control - It is nonetheless still a representative
simulation.
- Physical materials: samples collected by physical geographers in the
field that must be measured, typically in a lab, in order to produce
scientific data. (* the word sample will later be used to indicate a set of
cases smaller than the entire population of interest)
Physical Measurements in Physical Geography
Geodetic Measurement: measuring spatial properties of the earth and
features on it. Typically identified with the earliest origins of geography
as an intellectual endeavor.
Geodetic information can express two-dimensional planimetric
information and/or three dimensional elevation or altitudinal information.
Tools and techniques of geodetic measurement:
Triangulation - fixing point location by direction, trilateration- fixing point
location by distance, theodolites- a tool that measures direction through
horizontal and vertical planes, clinometers - measures heights
Physical measurements in Physical Geography
Physical Measurements of Earth Systems
Earth Systems
- Lithosphere: having to do with the earth surface crust
- Atmosphere: The enveloped layer of gases and other materials
surrounding the terrestrial surface. Of special attention to geographers is
the bottom most layer of the atmosphere called the troposphere.
- Hydrosphere: All embodiments of water and its movement through the
hydrologic cycle.
- Biosphere: This is all areas of the earth that is home to the living - plants,
animals, fungi, microorganisms…
Physical measurements in Physical Geography
Examples:
Each area of study has its own set of tools. Geographers studying
elements of soils may use sieve analysis to determine soil texture.
A soil profile can be dug to study the soil horizon.
Rain gauges, thermometers,
barometers, and hygrometers all
measure conditions, which together
help in understanding the weather
and the climate.
Physical Measurements in Physical Geography
Examples:
To study climates of the past, proxy
measurements must be used.
Proxy measurements are physical
measurements that are based on a
present trace of past climate conditions.
Tree cores, ice cores and pollen
analysis from sediments in ponds can all
be used as proxy measurements.
Physical Measurements in Physical Geography
Examples:
Radiocarbon dating is a technique for dating organic materials
based on their emission of beta particles from radioactive carbon14 and it is an important tool for dating soils and some other
organic material.
Drifters are a floating object dropped in the ocean and tracked to
measure ocean currents.
Physical Measurement in Human Geography
Physical traces refers too the physical evidence of humans in the
landscape.
Nonreactive measures such as physical traces are not susceptible to
reactance, which is changing behavior as a result of knowing their
responses are being measured.
Physical Measurement in Human Geography
The three actions that lead to physical traces:
Accretion - intentional or unintentional addition, deposition, or
accumulation.
Deletion - an intentional or unintentional removal, erasure, or
obliteration.
Modification - an intentional or unintentional change, alteration, or
conversion.
Physical Measurements in Human Geography
Functions of physical traces
1. Byproduct of use
2. Adaptation for use
3. Display of self
4. Public Message