Surveying-Chapter 28
metadata
"data about data", describes the content, quality, condition, and other characteristics about geospatial data and provides a record of changes or modifications that have been made to that data
nonspatial data
(attribute or descriptive data) describe geographic regions or define characteristics of spatial features within geographic regions
Spatial Data
(graphic data) natural and cultural features that can be shown with lines or symbols on maps, or seen as images on photographs
spatial joins
(overlaying) one of the most widely used spatial analysis functions of a GIS
point buffering
(radius searching) involves the creation of a circular buffer zone of radius R around a specific node
FEMA
Federal Emergency Management Agency
FGDC
Federal Geographic Data Committee
FIRMS
Flood Insurance Rate Maps
LIS
Land Information System
LULC
Land-Use and Land-Cover data
NFIP
National Flood Insurance Program
NSDI
National Spatial Data Infrastructure
NWI
National Wetlands Inventory
NRCS
Natural Resource Conservation Service
PLSS
Public Land Survey System
SCS
Soil Conservation Service
SSURGO
Soil Survey Geographic Data
Basic Data Classifications
Spatial & Nonspatial
TIFF
Tagged Image File Format
USGS
U.S. Geological Survey
topology
a branch of mathematics that describes how spatial objects are related to each other
topological relationships
connectivity, direction, adjacency, nestedness
interior areas
continuous space within three or more connected lines or strings that form a closed loop
line buffering
creates new polygons along established lines such as streams and roads
polygon buffering
creates new polygons around an existing polygon
proximity analysis
creates new polygons that are geographically related to nodes, lines, or existing polygons, and usually involved processes called buffering
points
define single geometric locations
direction
defining a "from node" and a "to node" of a chain
DEM
digital elevation model
DLGs
digital line graphs
DOQQs
digital ortho quarter quadrangles
DRGs
digital raster graphics
precedence coding
each category in the vector data is ranked according to its importance or "precedence" with respect to the other categories
predominant type coding
each grid cell is assigned the value corresponding to the predominant characteristic of the area it covers
GIS
geographic information system
nestedness
identifying what simple spatial objects are within a polygon
adjacency
indicating which polygons are adjacent on the left and which are adjacent on the right side of a chain
lines & strings
obtained by connecting points
vector
points are used to specify locations of object such as survey control monuments, utility poles, or manholes
Spatial Analysis & Computational Functions
proximity analysis, boundary operations, spatial joins, logical operations
grid cells
single elements, usually square, within a continuous geographic variable
connectivity
specifying which chains are connected at which nodes
geographic information system
system of hardware, software, data, and organizational structure for collecting, storing, manipulating, and spatially analyzing "geo-referenced" data, and displaying both graphical and descriptive information resulting from those processes.
raster
the size of the individual cells defines the resolution, or precision, with which data are represented
pixels
tiny squares that represent the smallest elements into which a digital image is divided
TIN models
triangulated irregular networks
vector & raster
two different formats for storing and manipulating spatial data in a GIS
