Land Use and Mapping Population

Definition of Land Tenure

  • In simple terms, land tenure systems determine who can use what resources, for how long, and under what conditions.

Categories of Land Tenure

  • Private : Held by a private party, which could be an individual, corporate body, married couple, etc.
  • Communal: Held by a community in which each member has the right to independently use land
  • Open access: No right are assigned to anyone and no one can be excluded
  • State: A governmental or other public authority holds rights.

Land Administration

  • How land tenure and associated property rights are operationalized
  • In developed countries, involves an extensive array of systems and institutions
  • In less developed countries, is many times informally administered.

Public Land Survey System (PLSS)

  • US system for administering the transfer and sale of public lands to private parties following the Revolutionary War
  • After US gained independence, the federal government wanted to reward soldiers for service and raise money for the new nation
  • Before this could happen, a way to partition the land had to be quickly devised

Why do we still use the PLSS

  • Roads and property lines have been aligned to sections of land
  • Federal and state land administrations are subject to the boundaries of the PLSS
  • Private landowner records are tied to the system
  • BLM ensuring GIS data of the PLSS complies with FGDC guidelines

Population Data

Why Map People

  • To study effect of population, topography, and housing on mortality
  • Different geographies (ward, neighborhood, district) used
    • Problem: district boundaries change and geographic framework changes

Census Spatial Data

  • Census data contains two types of flies:
    • Spatial boundaries (without population information)
    • Population information (spreadsheets; NOT spatial)

Land Use

  • Land Cover describes what is physical on the land
  • Land Use describes how people use the land
  • Zoning is a spatial, legal framework for how people are permitted to use the land (but not necessarily how it is actually being used)

Dasymetric Mapping

  • Redistributing quantities (population) through areal interpolation using selected variables and ancillary data
  • Essence: combining census data with land use data (of your choices)

Population Mapping Key Points

  • Land Administration (property rights, ownership, taxation) is separate from how populations are mapped, but can play a role given land use
  • Important to know the geographies of people to study the impacts of X on people and place
  • Most aggregations can be problematic for one reason or another
  • One solution is to map population data combined with additional data to tell us where people are not
  • Gridded population does not solve all MAUP of mapping populations

The Roles of Tables

Databases and Spatial Databases

  • A database is an organized collection of data in a digital environment
  • A spatial database is designed to optimally store spatial data, and can also store aspatial data

Geodatabase elements

Topology

  • Topology is the spatial relationships among a data features and sets
  • There are many different ways to define and enforce spatial relationship rules
  • Examples: adjacent polygons have shared edges; no gaps between polygons; lines can either share segments or not; lines can share nodes and points can be nested within lines, etc.

Attribute Tables

Attribute Types in .gdb

  • Numbers: Can be one of four numeric data types: short integers, long integers, single-precision floating-point numbers, and double-precision floating-point numbers
  • Text: Any set of alphanumeric characters of a certain length
  • Date: Holds date AND time data
  • BLOBs: Binary large objects are used to store and manage binary information such as symbols andCAD geometries
  • Global identifiers: Global ID and GUID data types store registry style strings consisting of 36 characters enclosed in {}; uniquely identify a feature or table row within a geodatabase and across geodatabases; used to manage relationships especially for data mangement, versioning, change-only updates, and replication

Measurement Attributes

  • Attribute type, how it is saved, and the level of measurement if allows: Nominal, Ordinal, Interval, Ration

The Importance of Attribute Tables

  • Descriptions, measurements, or classifications of the geographic information on the map
  • Tables can be joined to features by a “relationship” (Relational Join)
  • Tables of information can be joined to feature s based on spatial reference alone, no need for the common “key” (Spatial Join)

Relationships Between Data Sets in an RDBMS

Geodatabse as Obhject-oriented Model

Relational Database and Tables

  • Tables in a relational database design show the relations
  • Tables are related through one or more columns that meet certain requirements and may be used to index the rows = keys
  • Keys are often assigned with unique number of code
  • Three types of relationships between entities: 1:1, 1:Many, Many:Many

Structured Query Language (SQL)

  • SQL is a language used to communicate with a data base. SQL lets you access and manipulate databases, spatial or aspatial

Summary