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Creation of the �E3 Statewide PLSS �Database

By:

Tom Kazmierczak

David Vogel

Ana Wells

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Background

Sub-project of the greater Statewide Parcel Map Database Project

Uniquely identifiable local-level PLSS data

Requires local level PLSS coordinate information (coordinates, CRS, datum & adjustment)

Allows for an accurate on the ground location of PLSS corners & more accurate representation of polygon layers

County contributed corners
GLO Landnet
SCO Points

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E3 PLSS Database Characteristics

447,692 total corners

245,064 county contributed corners
194,799 GLO Landnet
7,143 USFS
686 SCO Points

Complete Geometry

Horizontal Accuracy

Tie Sheets Online

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Data Access Options

Downloadable File Geodatabase

Feature Services

E3 PLSS Corners
E3 PLSS Sections
E3 PLSS Quarter-Sections
E3 PLSS Quarter-Quarter-Sections

Survey Control Finder

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Creating the PLSS Points

Counties submit their PLSS data as part of their parcel submission, usually in a feature class

Although the feature class has its own geometry, we use the X and Y coordinate attributes to create new points instead of using the county’s points as-is

No way to verify the accuracy of the county’s geometry
Submitted feature classes use projected coordinate systems that would need to be reprojected into geographic coordinates (e.g. lat/lon)
Allows us to identify errors in the X and Y attribute fields that otherwise would have been hidden if we used the county’s geometry

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SDMS Translator and NCAT

To convert the county-submitted points into true PLSS points we use two programs: SDMS Translator for converting projected coordinates into geographic (latitude/longitude) coordinates and the NGS Coordinate Conversion and Translation Tool (NCAT) for converting to the correct datum

SDMS Translator cannot do datum transformations and NCAT cannot handle Wisconsin county coordinate systems (WCCS and WISCRS)

Time needed to process a county’s submitted points varies based on the number of unique combinations of datum adjustment and coordinate system. Each combination must be processed through SDMS translator separately

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Common Data Ingestion Issues

Missing or duplicated IDS

Every PLSS point must have a unique contributor_corner_id value, otherwise they cannot be accurately located
Contributor_corner_id is accurate within a county only
All records with missing or duplicated values isolated and returned to the county

Questionable or missing coordinate data

Usually X and Y reversed, an extra digit added by mistake, or the coordinates do not match the coordinate system
These are flagged for review by the county that submitted them and when possible, corrections are made, otherwise they do not have a point generated

Missing or ambiguous datums

A datum that is missing or lacks an adjustment (e.g., “NAD 83”) means that a point cannot be placed according to the standards established for this project
All PLSS points in the database are designed to be as accurate as possible and making assumptions for missing or ambiguous datums lowers the overall integrity and quality of the dataset
Historical data from previous editions can sometimes be used to identify datums (particularly if there is only one adjustment for an entire county), otherwise points are not placed

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Romportl Number Creation�Wisconsin Corner Point Identification System

11-character code used to locate each corner point within the statewide PLSS database

Romportl Number after Mike Romportl, Oneida County Surveyor

Components: DTRSC (Principal Meridian Direction, Township, Range, Section, Corner Number)

Wisconsin Statewide PLSS Romportl Numbering System in (https://www.sco.wisc.edu/wp-content/uploads/2020/08/romportl-standard-ver2-07192019.pdf)

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Romportl Number Creation

Romportl Number or

all components

Most components

Few or no components

County Provided Data

Creation:

Use Romportl number or components from native data

43 counties provided native Romportl number or all components.
17 counties provided enough components to create a Romportl number.

Spatial join using GLO landnet corners

12 counties provided few or none component to create a Romport number.

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Display Point Selection

Need to select the most accurate corner of multiple realizations of a PLSS corner
Require for generating polygons

A single point for each corner
Goal: select county points as much as possible

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1. Multiple representations of a PLSS corner

Horizontal Accuracy �(survey grade, sub-meter, approximately, unknown)

Tie Sheet URL

SCO criteria (historical knowledge)

No Accuracy, default to GLO Landnet

Only GLO Landnet exists

Selection Criteria

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Section corners and quarter-section corners from original GLO survey�
130,707 county submitted points
63,782 GLO Landnet points
680 SCO points

Display Points Selected

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Polygon geometry was derived from most accurate corner coordinates.
Section geometry was created connecting corner or meander points in E3 (GLO and non-GLO surveyed).

2. Single point for generating polygons

We are here

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q-section and qq-section polygons

quarter-quarter-section polygons were created connecting corner or meander points in E3 (GLO and non-GLO surveyed).
quarter-section polygons were created by aggregating the four corresponding quarter-quarter-section.