Monday, May 18, 2015

PLSS CadNSDI – PLSS Special Surveys (Non-Rectangular Surveys)

This is the seventh of a series of documents that describe the contents of the PLSS CadNSDI data set.

PLSS Special Surveys are non-rectangular PLSS surveys.  They are deviations from the hierarchical rectangular surveys, are often defined or guided by provisions of legislation or authorities.  PLSS Special Surveys can “sit on top” of rectangular surveys or they may replace the rectangular surveys, creating a “hole” in the rectangular surveys.  In some cases a nominal rectangular survey is extended through the special surveys. 

The PLSS Special Surveys are not populated for the many eastern states data sets because at the time of the PLSS Surveys in the eastern states, the non-rectangular survey types had not been well established.  Also in the eastern states many of the non-PLSS areas were defined before the PLSS and were never in the public domain.  However, for purposes of transition in some of the eastern states PLSS the non-PLSS data are in the PLSS special surveys, this will update over time.

The other item of note in western states lands that were not in the public domain, such as Land Grants, is in the PLSS Special Surveys, but may transition to the Survey System feature class over time.

Each PLSS Special Survey feature or parcel has one survey type designation.  The PLSS Special Survey parcels may overlap.  The attributes for this feature are listed below.

Unique identifier for a PLSS Special Survey feature
Survey Identifier
Code for the type of special survey.
Survey Type Code
Special survey type text description.
Survey Type Text
Special survey number or designator that identifies the special survey polygon
Survey Number
Special survey suffix designation that makes the identification of the area unique.
Survey Suffix
Notes about the polygon feature that are important for using or understanding the feature. From the BLM SurvNotes are A = Approximate Acreage, C = Conflict or Questionable, D = Non-added Acreage, R = replaced
Survey Note
The name or designation for any division of a PLSS Special Survey such as Lot in a Tract
Special Survey Division
Label that is used for cartographic output or web display.
Survey Label
The record or recorded area as a text field. This may include the units of area as well.
Record Area Text
The record or recorded area as a numeric field
Record Area Number
The area of the feature in acres - computed from the GIS, this is not the record area.
GIS Area Acres
The reference to the source document could be a reference to a map or plat or a deed. This could include document type.
Source Doc Link or Reference
The date of the source document
Source Doc Date

The Survey Identifier is included in this feature but it is not fully populated in the data sets.  The original intent was to define a unique identifier for each special survey type, for example, most mineral surveys are uniquely numbered in the state and tracts are uniquely numbered within a PLSS Township, but this work was not completed in the initial data sets.

The domain of values for the PLSS Special Surveys is listed below.  These codes and types come from the BLM records system and are used to match the special survey parcel to federal records.  Over time it is expected that the description will be relied on much more than the codes.

Special Survey Type Code
Special Survey Type Description
Tract - Other than cadastral survey
A tract other than a cadastral survey tract is a piece of land that has the term tract as its designated land description on a survey document.  The lands will typically have a number, name, or letter designation.
Allotment Survey
Allotment Survey is an allocation of discretionary assignment of lands.
Metes and Bounds
Metes and bounds surveys are required to define the boundaries of irregular areas of land, which are not conformable to rectangular subdivisions. Metes and bounds PLSS Special Survey Types are coded as a metes and bound if no other non-rectangular survey type can be identified.
Farm Unit Survey
Farm Unit Survey
Land Grant
A Land Grant is a portion of land that was claimed and occupied by a foreign power or government prior to survey.  Land Grants are not the same as Grants of Land made to individuals prior to survey.  Neither the Land Grant nor Grants of Land are part of the PLSS as the rights to these lands existed prior to the public land survey.  The boundaries of these lands form a closing line for the PLSS surveys.
Homestead Entry
Homestead Entry is a metes and bounds survey made under the Homestead Act defining lands acquired under an entry for the purpose of acquiring title.  Homestead Entry Surveys are numbered sequentially and uniquely within a state.
Indian Interest
This code and domain was originally Indian Allotment but has been expanded in the standard domains to include all Indian Interest lands including allotments, reservations, and other lands.
Small Tract, Small Holding Claim
The survey made to delineate the tracts differs from a townsite survey in that it normally follows a pattern of progression subdivision down to the desired lot sizes without block designations or the segregation of streets and alleys. Regulations provide for reserving rights-of-way in the patents or leases.
Mineral Survey
A Mineral Survey is a lode claim, placer claim, or mill site established to mark the extent of public lands claimed for the development of minerals and intending to become a private interest.  Not all mineral surveys complete to a patent and those that do not complete are reverted back to federal ownership in most cases.
Townsite Survey
There are many provisions for the executive withdrawal of public lands for townsite purposes. A townsite survey is a survey made within one or more regular units of the township subdivision by which the land is divided into blocks, streets, and alleys as a basis for the disposal of title in village or town lots.
Townsite Block
A Townsite Block is a block within a townsite.  The Townsite Block needs the townsite designation to uniquely identify it.
Townsite Outlot
A Townsite Outlot is a lot designated for public or community use within a townsite. 
BLM Parcel
BLM Parcel
Donation Land Claim
Donation Land Claims are portions of land that are 160 or 320 acres in size granted under the Donation Land Act of 1850 to citizens who resided in the Oregon Territory.  These are not the same as donation lands that were public lands donated or granted as an incentive for construction, such as railroad donations.
United States Survey - Alaska Only
United States Surveys exist only in Alaska.  These are similar in form to Townsite Surveys and provide for the disposal of public lands for occupation and settlement.
A tract is portion of land that protects a bona fide right.  Tracts are metes and bounds surveys that define the perimeter of lands settled between the time of the plan of survey and the actual field survey.  Settlement occurred following the boundaries intended to be as defined in the rectangular survey but do not conform to the actual rectangular survey.  Tracts are always contained within a PLSS Township and PLSS Township lines encompass the tracts.  Tracts are numbered within the Township taking the next highest number available after the highest section number. 
An exchange survey is a portion of land that has been described to support the exchange of private lands and public lands.  These are metes and bounds surveys.

The image below shows a cluster of mineral surveys and the surrounding rectangular lots and aliquot parts

Mineral Surveys and Rectangular Surveys
This same area without the special surveys appears to have “hole” in the second division.  This same “hole” will not be apparent in the Township and first division, at least for the mineral surveys.

"Hole" in Rectangular Survey
In other cases the non-rectangular surveys will sit “one top” of the rectangular surveys and the rectangular portions will continue under the special surveys.

Rectangular Areas Under Special Survey
The image below shows a Tracts and PLSS first divisions (Sections).

Tracts and Sections

The Tracts are non-rectangular parcels that typically start with number 37 in a township to distinguish them from sections.  Technically, Tracts are metes and bounds surveys that delineated lands that have an established right established prior to the rectangular survey typically by occupation.  This occurs when the land was settled prior to survey and the occupants intended to occupy a section or other parcel of land described from an unsurveyed plat.  When surveyed measurements of the protected rights determined that the occupied land did not conform to the rectangular survey, a tract is defined.  By definition the tract is described by PLSS Township and the Tract number.  The PLSS Township boundary should encompass the outside boundary of the tract.  However, this can create a “notch” or “protrusion” on the township boundary and in some cases the theoretical township line is extended through the tract.  Tracts numbering begins with the number 37. In the image above Tracts 38 to 40 are PLSS special surveys. 

Another PLSS Special Survey is the Townsite, coded as special survey type N in BLM records.   The polygons labeled in the figure below as “K ##” are the Townsite blocks, special survey type code K in BLM records.  In the PLSS a Townsite survey is a special survey that divides the land into blocks, lots, streets, alleys, rights of way, and reservations forming land descriptions for the disposal of title.  The key word is disposal.  Townsites, through a variety of acts and authorities, are intended to pass the land from federal to private ownership.  However, there may be parts of Townsites that remain in federal ownership or are re-acquired back to federal ownership. 

Townsite Survey

In this case the roads (coded as Townsite survey) plus the Townsite blocks would form the complete Townsite survey. 

There are many other types of non-rectangular surveys in the public domain and each will have a designated authority and survey rules.  Not all special surveys are found in all states.  It is best to consult with the state BLM Office or the state data steward for special survey situations that are irregular or not clear in the PLSS CadNSDI data sets.

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