Geography 103 UOA

data model

conceptual understanding of how information is organised

data structure

the implementation of how data is transferred from real life to the digital

Fields

surfaces as a continuously changing and graded reality

objects

independent features arranged relative to one another

atomic vs plenum

when does one thing become another thing? or are all things seperate from one another?

Raster Data

A grid-based format for storing location-based data in a geographic information system in which each equally-sized cell or pixel contains a value that represents geographic features.

Vector Data

A format for storing location-based data in a geographic information system that uses latitude and longitude coordinates to represent geographic features with points, lines, and polygons

tabular

from non-spatial tables

drone

from above, location, scale and orientation required perspectives

analogue to digital

stored so computers can recognise it

Analogue data

fixed information, scale down models using analogies

Digital Data

data not fixed, using coordinates and an attribute table

coordinates and projection

ties information to the ground using scalar units

WGS84 (World Geodetic System 1984)

latitude and longitude, degrees + minutes + seconds, often continental
cannot b used for small projections - small units

NZTM2000 (New Zealand Transverse Mercator)

from central datum, distance + area. cannot b used for large projections- large units

Spatial data (geospatial data or geographic information)

links a location and an attribute, contains specific geographic information

Primary Data Collection

surveys, observations, experiments

secondary data collection

processed primary data

raw data

data collected in original form, unprocessed

Size Hierarchy

national > regional > TLA > wards > SA2 > meshblocks/SA1

Surveying

primary, involves determining positions of points, distances and angles

census

secondary, processed surveying

Sonar (Sound Navigation and Ranging)

a primary system that uses reflected sound waves to detect and locate objects underwater

LIDAR (Light Detection and Ranging)

A remote sensing technique using the same principle as radar. The instrument transmits light to a target, some of which is reflected back to the instrument. The time for the light to travel out to the target and back is used to determine the range to the target.

satellite

A natural or artificial body that revolves around a planet

Highly Elliptical Orbit

communication at northern latitudes

geostationary orbit

communication and weather

Low Earth Orbit

mobile communication, astronomy and reconnaissance

GPS (global positioning system)

A system that determines the precise position of something on Earth through a series of satellites, tracking stations, and receivers.

passive sensors

only detect energy emitted or reflected off targets

active sensors

emit their own energy and record reflection off targets

spatial analysis

going beyond the database to create new attributes and geography. extraction/creation of new data

local operations

cell by cell

Focal Operations

calculates a value based on all neighboring cells

neighborhood operations

approach to raster image analysis, focal statistic tool performing operations

area/distance measurement

no spatial analysis, computually non-trivial in vector

Spatial aggregation

sampling down large rasters

kernel

small matrix, used for blurring, shaping, edge detection via a convolution of a kernel and an image

Kernel Density Estimation (KDE)

estimate a continuous density surface, used for hotspot mapping of concentration of events. one of the most useful empirical models of spatial data

Network Analysis

system of nodes and edges

intersection

new geometry

clip

new geometry, boundaries of second polygon imposed on the first

Union

new geometry, groups geometric features

dissolve

new geometry, removes boundaries of adjacent features with identical attributes

buffer

new attribute information, distance function that selects areas within a specified distance

reclassification

new attribute information, assigning new classes of values to existing values

data query

questions posed to a database, turns out selected spatial objects

Structured Query Language (SQL)

an international standard language for processing a database, no new data created

spatial data query

query based on spatial relationships