Midterm 1 Flashcards
(38 cards)
Give two examples of software in GIS
Like arcmap, arctoolbox, arccatalogue (the three components of GIS)
What is raster data good for?
Continuous data, layers, satellite or orthophoto
What are some things vector is good for?
Querys, buffers, watersheds or eyesheds, routing, overlays
What is GIS?
Stands for geographic information system
Integrated set of components that operates on spatially explicit data to generate new information and understanding for aiding in decision making
What is vector?
Lines with coordinate plus data tables
What is raster
Grid of cells (pixels) with values like a spreadsheet
What are the three levels of arcGIS?
Arcview, arceditor, arcinfo
What are the three dimensions of spacial data?
Time, spatial(discrete or continuous) and attribute(non spatial info about a feature usually stored in tables and may include string or field info- about how it should be displayed)
What are the most common prjections used for mapping in bc?
Universal trans mercator UTM
Albers equal area (conical with standard parallels)
In arcgis what is datum?
What version of best fit lat and long
Like NAD83 or 27
Datum is “the reference specs of a measurement system, usually coordinate systems horizontal or vertical”
In gis Define discrete and continuous data and an example of each
Discrete has definite boundaries like a stream or road.
Continuous varies without steps or boundaries (“infinite” possibilities)
Three types or digital capture of gis data?
Scan
Digitize
Keyboard entry
The three sources of gis data?
Gis map data (base maps like geobc topo, forest cover maps) Remote sensing (lidar, satellite, orthophoto) Field surveys (gps, roadeng, cogo)
How does satellite imagery work?
Using energy from the sun, satellite sends beam to earths surface which is reflected back to the satellite sensor and ten beamed tom a recieving station
Explain how digitizing works
Using computer program drafting assists, or manually trace in tracing tablet
Can use point mode- tracing points and the computer connects them- or streaming mode- where you literally trace and the computer streams out sets of points
Heads up digitize where you trace with mouse or pen on advanced screens
Explains steps of scanning
Generate a raster image by letting computer read a map as an image
Then you vectorize- well, the computer does this
Optionally give spatial references to at least four corners to georeference
Two editing processes within gis data?
Detect and correct errors
Update or maintain database
What are some errors that can happen with editing?
Sloppy work errors- Poor tracing Sliver polygons Under and overshooting Missing or duplicate features
What are some types of generalizations
Line smoothing
Weeding coordinates or thinning a line
Combination, selection, omission
What is topology?
A way of defining how two features share a boundary
What are some other kinds of geometric transformations? Than projection matching
Datum matching
Edge matching
Rubber sheeting
List four types pf geometric transformations
Convert projection, datum, rubber sheeting, edge matching
What are the 5 concepts to consider in cartographic design?
CHSME
- Concept before compilation- know purpose and audience
- Hierarchy with harmony- intellectual (critical elements), visual (size and location and figure ground relationship)
- simplicity from sacrifice- use generalizations
- max info at minimal cost- have an effective design
- engage emotion- good maps are art
What are some non map outputs?
Cartogram- cross between map and diagram
3d resemtations
Animations
