The linear transect:
A very common and useful reconnaissance technique is the linear transect. A linear
transect allows the geographer to extrapolate a limited set of field observations into a
description of a fairly large area. In some situations, a linear sampling scheme may be
the only viable option for field checking of remote sensing data. For example, vegetation
mapping of the vast interior of Siberia… without a massive investment in a field
campaign it would be impossible to perform a true random sample. The proposed
solution was a stratified linear random sample. The few transport corridors would be
buffered and samples taken, producing a statistically viable sample with much less
Linear transects are usually laid out along paths of easy transport… while this can limit
their statistical viability and leads to a biased sample… the short answer is that they are
cheap, easy to lay out and often one of the best tools available for initial recon. of a field
In your write up please consider how urban/industrial/commercial development might
bias a linear transect.
Please visit http://www-personal.umich.edu/~kkoo/up538handbook.html
And read a bit about one of the more notable theories of development across space.
It is very important to record data during your transect. In educational theory it has
been noted that we remember what we first see (primacy), what we last see (recency),
and that which has a significant impact (the „oh wow‟! factor). If a geographer makes a
transect without the discipline to record accurate notes, he or she may „remember‟
differently and again produce a biased result. In this exercise, you will record data at ½
mile intervals along your transect.
The ‘grain’ of the landscape:
Landscapes have patterns, this is one of the key understandings in geography, which can
be defined as a search to identify and understand the patterns of a landscape.
In many cases it is desirable to construct the transect across as many features / factors of
the landscape as possible. In many places the gradient on the landscape will be elevation
and or climatic. Here in Northern Alabama it appears that the „grain‟ of the landscape, in
general, follows the Tennessee River. It should prove to be more instructive and produce
a better sample to cross the landscape at right angles (or something approximating right
angles) to the development along the Tennessee River.
Working in pairs for driving safety, identify a series of roads that will lead you across the
landscape roughly perpendicular to the development corridor of the Tennessee River.
Make sure you reach at least 10 miles North and South across the river. (if you see
interesting/significant features in the next couple of miles, feel free to add a little to your
transect). Record the land use/land cover at ½ mile intervals along your route. Record
changes in elevation, changes in vegetation, changing land use, changes in development
density. In your write up, provide a final version of your field notes. Add a map that
shows the route you chose for the transect, and describe changes in the landscape.
Quantify the landscape based on your data points (X% forest, Y% pasture, Z%
commercial etc….Use Anderson‟s level 2 classification categories). Compare these
percentages with your knowledge of the area, are your percentages a fairly accurate
representation of the area as a whole? Evaluate the transect you chose, is it representative
of the area? Demonstrate in your discussion that you have a good understanding of the
„central place theory‟ and how development will follow transport corridors. Are there
significant differences (cultural/agricultural/development) between the North and South
sides of the river? Are the differences in the landscape a function of distance from the
river? Or are other factors involved?
Table 1. A part of the modified Anderson classification system illustrating
subcategories included in the "developed" land use category
Level 1 Level 2 Level 3 Level 4
2.0 2.1 Residential 2.11 Single-family
2.2 Nonresidential 2.21 Commercial/Light 2.211 Major retail
developed Industry 2.212 Mixed/minor
retail and services
2.214 Light industry
2.22 Heavy industry
2.3 Mixed urban