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Lecture 03 - Relational Databases Primary Key attribute value which allows users to uniquely identify a row in a table Secondary Key – attribute value which must also be used to uniquely identify a row in a table Tuples – occurrences of an entity (a row in a relational table) Foreign Key – an attribute (in a relation) that is a primary key in another relation SELECT <attribute(s)/field(s)> FROM <table(s)> WHERE <condition(s)> Structured Query Language SELECT [lucode] FROM [lumap] WHERE [area] > 100 and [location] INSIDE [orange county] CREATE DELETE INSERT ALTER UPDATE … (run first)

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Microsoft PowerPoint - L03_Slides_v20200105.pptLecture 03 - Relational Databases
Primary Key – attribute value which allows users to uniquely identify a row
in a table
Secondary Key – attribute value which must also be used to uniquely identify
a row in a table
Tuples – occurrences of an entity (a row in a relational table)
Foreign Key – an attribute (in a relation) that is a primary key in another
relation
Structured Query Language
SELECT [lucode] FROM [lumap] WHERE [area] > 100 and [location] INSIDE
[orange county]
3) Linking of spatial and attribute data
Digitization? Polygon: Last Point = First Point
Topology And Vector Operations
Planar Enforcement: area objects in one class or layer cannot overlap and must
exhaust the space of a layer (Topology – how objects relate to each
other)
Point In Polygon, Line On Polygon, Polygon On Polygon (Transfer Rules?)
(Subtract)
(Dissolve)
(Merge)
Attribute Operations:
On one or more attributes of an entity
On one or more attributes of multiple entities that overlap in space
Distance/Location Operations:
Locate entities with respect to simple distance (Euclidian) or location
criteria
Spatial/Topological Relations:
Do objects overlay?
(i.e. Vector vs Raster?)
Mathematical/Logical Operations for
Simple/Complex Arithmetical
Excel Formulas; SQL Functions; External software (Statistica, S-Plus, SPSS, etc …)
Buffering (Simple Distance; Spatial)
Operations That Depend on
Interpolation Spatial Filtering
Contiguity assessment (clumping) drainage networks and catchment delineating
Non-linear dilation Viewsheds, Shaded relief, irradiance
(spreading with friction)
Digital Elevation Models
Maximum Downward Gradient
(Rate of change of slope) (Rate of change of aspect)
Surface Representation: 2D – DEM/Grid
Allows calculation of drainage networks and streams, watersheds,
drainage divides/ridges (movement of erosional material and water flow)
Local drain direction (ldd)
Stream Channels (how many cells feeding this one)
Ridges (Cells with no upstream elements – nothing feeding them)
Catchments/Watersheds
Least Cost Routing
Shaded Relief
Example – Specific GIS
Questions
Provided with a digital elevation model (DEM) and a table containing (x,y)
locations and zinc concentration (POINTS) outline the methods by which you
could determine those areas which have zinc concentration >100mg. Express
this as a percentage of the total area being examined.
Given a raster surface, LANDUSE and two vector drawings, PRECIP and
ROAD_BUFFER_200M, describe the methodology to determine those areas
with: an agricultural landuse; precipitation between 100 and 200mm; and
within 200m of a road. Use only vector operations.
A
B
Example – Specific GIS Questions
You are hired as a consultant to do an initial search for possible sites on which to locate a
landfill. You have: basemaps for the area (which also include road types and water
courses); a vegetation map; a landuse map; a hazardous waste site map for the area; an
archeological site map for the area; a DEM.
Your restrictions on determining possible sites are as follows: the landfill site cannot be
within 500m of a water course/body, wetland/marsh, existing waste site or archeological
site. The population density must be less than 1 person per square kilometre. It cannot be
located on prime agricultural land. It must be located within 300m of a paved two or four
lane highway/road. The area must be relatively flat (less than 5 degree slope). The area
must be larger than 200 hectares.
Your final image must show all areas which fall within the imposed restrictions.
C