GIS Exam Flashcards
(34 cards)
What is data?
-Raw data is a collection of seemingly random, disorganised facts or numbers
What is information?
-When data is processed, organised, structured or presented in a given context
What does GIS stand for?
Geographical Information System
-It is a system, not a computer application
How is GIS important regarding marine and freshwater science?
-Document baselines
-Highlight protected areas
-Appropriate Assessments (Natura 2000)
-Monitoring obligations (operation licenses)
What are 6 functions that GIS is capable of?
- Capture data
- Store data
- Query data
- Analyse data
- Display data
- Output data
How can you collect spatially defined environmental data?
-Remote sensing
-Acoustics instrumentation, side scan sonar, multibeam echosounders
-Broad scale habitat mapping
-Bathymetry
-Surface relief/ substrate types
-Areas of interest, features hazards
What can targeted remote imaging do?
-Video data from ROVS / cameras
-Confirm type pf substrates (sand/mud)
-Confirm features (sand waves, possible reefs)
-Trawl marks, drill holes, cable routes
-Sensitive habitats and species
What are the types of GIS spatial data?
-Vector
-Raster
-Tabular
Describe what vector data is
Points, lines and polygons (x,y)
Describe raster data.
Row and column matrix (georeferenced digital maps)
-Eastings and northings
-Soil data or land use
-Continuous data, spectral data from satellite imagery or aerial photographs
-Used as basemaps, surface elevation, seabed bathymetry
Describe tabular data.
Attribute tables (csv or txt tables)
What is data integration?
-Collection of geographic datasets of various types (tables, shapefiles, maps) held in a common file system folder
-Each dataset is a separate file on disk, but all datasets that belong to one geodatabase are contained in a single folder.
Where can you access GIS data?
-Marine institute
-EPA
-Irish government
-From ESRI (ArcGIS)
-EU
What are coordinate systems?
-Are location reference systems for spatial features on the Earth’s surface.
-Provides a common basis of communication about a particular place or area on the earth’s surface
What are the two types of coordinate systems?
-Geographic (Global coordinate system
-Projected (can be global, continental and local (national)
How are geographic coordinate systems defined?
-Defined by longitude and latitude
-Angles measured from the earth’s centre to a point on the earth’s surface. Measured in degrees
-eg. 55 N, 45 W
What are parallels?
- Latitude, reference equator (0)
What are meridians?
Longitude, reference Greenwich
What is the origin?
Intercept of Prime (Greenwich) Meridian and Equator
What are geodetic datums?
-Determines how the coordinate system aligns with the spheroid used to the reference ‘centre’ and so do the coordinates
-Due to Earth not being a perfect sphere
What is the most common coordinate system used?
WGS84 (global)- Global Positioning System GPS
What are three examples of geocentric coordinate systems that use satellite technology?
-WGS84
-GRS80
-ITRS
What is a projected coordinate system?
Is defined on a flat, two-dimensional surface (it is a projected sphere)
-Distances are measured in linear units (metres)
-Each position has two values that reference it to that central location (origin). X or Easting horizontal and Y or Northing vertical
What does UTM stand for?
Universal Transverse Mercator
(Global projected coordinate system)
