This blog site is a discussion site for national parcel and cadastral data to support the Cadastral NSDI. The FGDC Cadastral Subcommittee coordinates the activities and standards for the Cadastral NSDI. The implementation depends on parcel data producers and access through trusted data publishers such as states.
Monday, May 18, 2015
PLSS CadNSDI – Meandered Water
This is the
eighth of a series of documents that describe the contents of the PLSS CadNSDI
is NOT hydrography. These are areas of water that are defined from meander lines of
the PLSS, typically as shown on the original Government Land Office (GLO) or
recent BLM survey plats. These are not the official representations of coast or
water lines and are representations of the lines marked by the survey along the
boundaries of meandered water at the time of survey
There is no attribution
with the meandered water feature class other than a special survey type code
indicating it is water.
water is perhaps one of the more confusing feature classes in the PLSS
CadNSDI. The meander lines were run on original surveys to separate
the uplands from the water. In some cases these lines became legal
boundary lines and are called out in land descriptions. In other
cases the water’s edge is the legal boundary and the meander line is only an
approximation of the water.
If the PLSS
CadNSDI data set originated from digitized USGS topographic quad sheets, which
is relatively common I the eastern states, then the meandered water feature is
empty, unless a survey plat or local data set has been used to update the
original data set. This is because when comparing the digitized PLSS
to survey plats it was noted that hydrography, water captured from a source
other than the survey plat, often took precedence over the PLSS meandered
water. In some cases areas delineated as land in the original survey
were omitted and in other cases land was extended to meet current
It is critically
important that the use of the water boundaries in the PLSS CadNSDI be used as a
general reference only and the specific information about basis of land
descriptions and the intended representation of water versus upland be well
understood for any legal applications.
below illustrates the many varied ways that meandered water may be presented in
the PLSS CadNSDI.
The first thing
to note is that the meandered water is “broken” at PLSS Township
boundaries. This means that no meandered water polygon should be
larger than a Township. This makes selecting and working with these
polygons more manageable in a GIS.
Notice that the
water body in the upper left completes or fills in the “hole” created by the
meander in the township, while the meandered water boundaries on the right side
are not closed into polygons and do not “fill in” the Township. The
meander line is a boundary not a polygon and as shown in the figure above it
may or not be closed to create a polygon.
Also note that
for the most part there are no rectangular or special survey features in the
meandered water areas. The meandered water separates the upland and
therefore the upland divisions would not be expected beyond the meandered
There are, of course,
exceptions.In the image below parts of
Lots 2 and 3 extended into the meandered water. It is possible that these two
lots do end at the meandered water but a corner was added in the lake to
compute acreage or to complete a polygon.In some cases these areas can be changed or updated in maintenance.The configuration of township lines and
meandered water can also depend on the year and season of the survey.
In general meandered
water should be identified as a meandered water polygon that is “artificially”
divided into a polygons at the Township boundary.
“inland lake” where the section line is completed through the water. This
is typical for the smaller water bodies.
that the meandered water is segregated. This means there are
government lots that separate or segregate the meandered water from the
upland. This is also a fairly typical scenario since the regular rectangular polygons
would not be sustained around the water bodies. See the discussion in
the PLSS Second Division blog for more information
on the lotting.