GEOGRAPHIC INFORMATION SYSTEMS Lecture 11: Land Division Systems

Transcription

1 GEOGRAPHIC INFORMATION SYSTEMS Lecture 11: Land Division Systems Land Division Systems - in many applications of GIS, land ownership is an important data layer and it is important for GIS users to be familiar with the most common land division systems used to describe property - a land ownership (cadastral) layer might be a county parcel map, oil leases, or right-of-way easements - it is also important to note that land division systems can have a profound influence on the landscape - land division systems can strongly influence both land use patterns and road networks - these artifacts of various land division systems are often apparent on maps and remote sensing imagery - over the course of U.S. history, five major land division systems have been used Metes and Bounds - a very unsystematic and irregular land division system - property boundaries are defined by referencing fixed points, distances and directions on the landscape - for properties surveyed in the 1700 s and 1800 s, these fixed points were often trees, roads or streams - most widely found on the east coast of the United States Louisiana (French) Long Lots - land originally subdivided to provide farm access to river transportation - as land became subdivided, the original properties became more narrow, resulting in long lots - most widely found in areas settled by the French (Louisiana and the province of Quebec) Spanish (Mexican) Land Grants - property boundaries were established by large land grants - these land grants issued first by the Spanish crown and then later by the Mexican government - most widely found in areas settled by the Spanish (southwestern states) Public Land Survey System (PLSS) - also known as the Rectangular Survey System or simply Township and Range - a land division system originally devised by Thomas Jefferson - established by congress in 1785 for the purpose of subdividing land in new states and territories - land is subdivided based upon the intersection of a Principle Meridian and Baseline - additional survey lines were then laid out from that intersection at 6 mile intervals to form a grid - at regular intervals the grid is modified by correction lines to accommodate the curvature in the Earth - these 6-mile by 6-mile squares are called townships (covering 36 square miles) - the first township south of the baseline and east of the Principle Meridian is called T1S R1W and the other townships are numbered in a similar fashion. - each square mile within a township is called a section (there are 36 section in a township) - these sections are numbered in a snake-like fashion beginning in the north-east corner of the township - the sections can then be further subdivided to identify smaller parcels (e.g. NW ¼, section 22, T2N R3E) - note that Indian Reservations and a few remote mountainous areas are not subdivided using the PLSS Original Texas Land Survey (OTLS) - Texas is not part of the Public Land Survey System - at the time the PLSS was surveyed in the United States, Texas was an independent country - in parts of west Texas (e.g. Lubbock county), the OTLS looks very similar to the PLSS - this has produced the square grid of agricultural fields and the square street grid in city of Lubbock - in other parts of the state, the OTLS is very different - some parts reflect the Spanish land grants and some parts are similar to French long lots Copyright 2015, Kevin Mulligan, Texas Tech University

2 Copyright 2015, Kevin Mulligan, Texas Tech University

3 Copyright 2015, Kevin Mulligan, Texas Tech University

4 GIST 3300 / 5300 Land Division Systems Land Division Systems in the United States - metes and bounds - Louisiana (French) long lots - Spanish (or Mexican) land grants - Public Land Survey System (PLSS) - Original Texas Land Survey

5 Metes and Bounds - distances and boundaries - a very unsystematic method of land division

6 Metes and Bounds Follow the wall until you see a barn with a large oak tree on the left.

7 Metes and Bounds - metes and bounds stone marker in a field

8 Metes and Bounds - found mostly in the eastern states

9 Metes and Bounds Metes and bounds on a topographic map

10 Louisiana (French) Long Lots - mostly found in areas settled by the French (Louisiana and Quebec) - land was originally subdivided so each property (farm) had river access

11 Louisiana (French) Long Lots - as land was subdivided, farms became more and more linear

12 Louisiana (French) Long Lots Long lots on a topographic map

13 Spanish (or Mexican) Land Grants - large tracks of land (mostly for ranching) were granted by the Spanish government (and later the Mexican government)

14

15 Spanish (or Mexican) Land Grants - found mostly in the American southwest - California, Arizona, New Mexico and Texas

16 Grant labels and boundaries on a topographic map

17 Public Land Survey System (PLSS) - most of the U.S. was subdivided using the Public Land Survey System - also known as Rectangular Survey System or Township and Range Principle Meridian Base Line

18 Public Land Survey System (PLSS)

19 Public Land Survey System (PLSS) Township N-S designation Range E-W designation - area is referred to as a township

20 Public Land Survey System (PLSS) - each township consists of a 6 mile by 6 mile grid - with 36 sections

21 6 miles Public Land Survey System (PLSS) - each township cover 36 sq miles - each section covers 1 mi 2 (640 ac) - numbered in a snake-like fashion from north-east corner T2N, R3E Section 22 6 miles

22 Public Land Survey System (PLSS) - sections can be further subdivided

23 Public Land Survey System (PLSS) Sections on a topographic map

24 Original Texas Land Survey (OTLS) - at the time of the Public Land Survey, Texas was an independent county - in parts of west Texas the OTLS looks very similar to the PLSS - this has produced the square grid of agricultural fields - and the square street grid in the city of Lubbock - in other parts of the state the OTLS looks very different - some parts reflect the irregular shape of the Spanish land grants - other parts resemble the French long lot system