GLEI 1 Sampling Framework (Plot locations and segmentsheds)

These are GIS files providing sample point and plot locations, as well as the coastline segments and segmentsheds used in GLEI I analyses

Different GLEI-1 spatial units

The diagram illustrates some of the spatial entities described further below. In this example the complex would have an ID number like 1234 and the locales would have ID numbers like 456-2, 456-4, 456-5, which are sometimes seen as 456002, 456004 and 456005.

Each spatial entity is described by two paragraphs, one in general conceptual terms, the other covering database access information.


The coastline was divided into segments with somewhat arbitrary boundaries between second order streams. For stressor analysis segments and their boundaries are now being superseded by complexes (below). As shown above, segment boundaries may cross complexes and wetlands.

Segments contribute the segment number (seg_num) part of site (locale) id codes, but otherwise have a minor role at this stage.

Locale (site, poly_num, sampling event)

The term locale, as in locus, is used to describe the fundamental sampling event. Most subprojects' concept of a "site" corresponds to a locale. However a repeated sampling of a site at a different time would constitute a different locale, locales can be separated temporally as well as spatially. A complete replicate sampling of a site at the same time would also be a different locale. But not partial within site replication.

Locales are uniquely identified across all subprojects by a combinations of their segment number (seg_num) and their locale number (poly_num). Basic information about locales is stored in the a_locale table. The segment number may not reflect the segment the site is in, or the site may span more than one segment. As discussed above, segments are not particularly important at this stage. Each subprojects top level (location) record has a seg_num and poly_num field that can be used for linking to a_locale etc. Locales identifiers (the combination of their segment number (seg_num) and their locale number (poly_num) may be written 123-4 or 123004, although the latter form is usually only associated with ArcView.

Point, GPS point, sampling point.

A sampling event is made up of a set (locale) of points on the ground.

The server table a_point includes the seg_num and poly_num fields that identify the locale to which the point belongs. It also includes the X and Y coordinates of the point in GLEI-Albers projection, and the time and date the point was recorded, where available, and the id supplied by the subproject owning the point. There are some other fields (subproject, geomorph, etc.) but these are redundant with information in the server table a_locale, which should be used instead.


Complexes represent the "ecological unit" evaluated by a sampling event (locale). Where possible these have been drawn to include as many subprojects as possible. This may mean stretching a subproject's normal definition of "ecological unit", but is a trade-off to allow subproject overlap.

Complexes are identified by arbitrary unique numbers in the complex_num field of the a_locale table. Locales that share the same complex_num value are in the same complex.

Wetland-watershed (overland flow contributing area)

Stressors incident on complexes will be measured for a number of scales, one of which will be the area of land from which water and things carried by water would flow into a complex.

Wetland-watersheds have a one-to-one relationship with complexes and share their arbitrary unique id numbers.

Data and Resources

Additional Info

Field Value
Last Updated May 2, 2017, 13:05
Created November 9, 2015, 21:44