GIS & GISc Review
A review for Dr. Crews's second Environmental Science test! I'm probably not the most detailed note-taker in the world but hopefully this will help us all at least sort of pass the test.
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- What are some actions that can be taken at the top authority level regarding the Okvango Delta?
- Governmental and non-governmental bodies need to develop, implement and MONITOR sustainable management policies.
- What are the four ways of displaying continuous data?
- Equal interval, Quantiles, Natural Breaks, Standard Deviation
- What are the relationships involved in the electromagnetic spectrum?
- Frequency and energy share a direct relationship. As frequency increases, energy increases. Wavelength shares an inverse relationship with frequency and energy. As wavelength increases, energy and frequency decrease.
- How do you produce gray tones/white (additive color theory)?
- Equal amounts of all colors.
- What is subtractive color theory?
- Think mixing paint: the more colors get added, the darker things get.
- Describe the "equal interval" way of displaying continuous data.
- This splits the data into user-specified numbers of classes of equal width. Each class has a different number of observation.
- What are the main physical factors that contribute to the Okavango Delta?
- The Okavango system flows through a semi-arid area, forming one of the largest inland deltas in the world. It's moisture depends on the annual floods driving in Angola.
- Are vertical or horizontal GPS measurements more inaccurate, and why?
- Vertical measurements are more inaccurate because we do not really know the precise shape of the Earth.
- Described the nuclear community pattern.
- People live in one central area and go out and work the field in different directions each day.
- What is GISc?
- GISc is the computer science involved behind GIS. It incorporates related fields and their concurrent theory. GISc acknowledges the thematic science behind what we're studying.
- What is Aeolian Transport?
- The movement of soil particles by wind.
- Explain proportional symbol maps.
- These are the maps that scream "If you can make it some other way, please do!" They involve a lot of information displayed at the same time.
- GPS Error: Satellite Coverage
- Position dilution of precision (PDOP); if the satellites are grouped closely together, there is a bit more uncertainty as to where we are. Multiply total error by 1-6 meters (multiplicative, not additive).
- What is phenology?
- Seasonality
- What is the one distinguishing feature that separates images from photos?
- Images are made up of many different bands and have data behind them.
- What conflicts exist between the human factors and physical factors of the Okavango Delta?
- Livestock overgrazing contributes to erosion and desertfication; agriculture requires extensive land clearing; tourism is a fickle market that conflicts with the carrying capacity of the area.
- What is perpendicular deforestation and where is it common?
- This occurs when deforestation is achieved in a 90 degree manner; a straight road is put in (transportation) and perpendicular roads are laid against it. This is also called Piano Key or Fishbone deforestation)
- Describe the "standard deviation" way of displaying continuous data.
- This calculates the mean (average) of our data. This describes how typical or normal something is.
- How many satellites are in GPS's nominal orbit?
- There are 24 satellites in 6 orbital planes, 21 of which are working 98% of the time.
- What is the word for vegetation extracted for usage?
- Veld materials
- What word can be defined as data about data?
- Metadata
- What are examples of continuous data?
- Interval (temperature) and Ratio (precipitation [true zero])
- What does continuous data have that discreet data doesn't?
- Units
- What are the main human factors that contribute to the Okavango Delta?
- Humans use the Okavango delta for livestock, agriculture, tourism, water extraction, fishing, gathering of veld products, and hunting.
- What is the fastest growing industry in Botswana?
- Tourism
- How do you make magenta (additive color theory)?
- Blue + Red
- What does LIDAR stand for, and what does it entail??
- Light Detection And Ranging; This describes when an aircraft beams a laser back and forth on the landscape to pick up information that a computer can later interpret into a visual image.
- What is GPS and how is it used?
- GPS is a space-based 3 dimensional measurement and positioning system that operates using radio signals and satellites orbiting the earth. This can provide instantaneous position, velocity, and time information from almost anywhere on the globe by having the satellite send a communication signal to the device, telling us how far we are away from them in seconds. Taking advantage of the constant speed of light, we can infer distance.
- What is additive color theory?
- The opposite of subtractive color theory, the more colors get added the lighter things get.
- What can be done at the lower authority level regarding the Okavango Delta?
- Introduce sustainable land use practices, finding alternative methods of income generation, such as community based low-mid price tourism, and involving local communities in the decision making process.
- What are the two levels of data?
- Discreet and Continuous
- What industry employs the most people in Botswana?
- Diamond Mining
- What is spatial data?
- Spatial data is data with location information that ties you to a point in space. Using this, one can also tell relationships about things around oneself. The three components of spatial data are location (where is it located?), attribute (something about it), and behavior (spatial characteristics).
- What are examples of querying data?
- What exists at a particular location? Which locations satisfy certain conditions? (In general, these are why and where questions)
- Describe the perpendicular community pattern.
- People need to be near roads, so there is very little road front (to maximize the number of houses that can be near the road) and long, narrow plots.
- (Former) GPS Error: Selective Availability
- This error was intentionally introduced by the Department of Defense; entailed skewing the information given by satellites accessed by civilians for national security reasons; officially turned off May 1, 2000.
- What are the capabilities of GIS?
- 1) Capturing data 2) Store data 3) Query data 4) Analyze data 5) Display data 6) Output data
- What is the basic responsibility of a cartographer?
- To make sure that map successfully communicates the given information; it is ALWAYS the fault of the cartographer if somebody cannot interpret it the right way.
- How do you make Yellow (additive color theory)?
- Red + Green
- What is the consequence of water holding on to light energy?
- Water appears darker in images.
- What are the methods of storing data?
- Using a RDDMS (relational database management system), information can be shared in raster data (a set of uniformally square grid cells referred to as pixels) or as vector data (line shapes, more realistic)
- What is represented in a DEM model?
- Topography
- What information does each GPS satellite signal beam to Earth?
- Satellite number, time of transmission, and navigation/broadcast data
- What is the definition of remote sensing?
- • From a satellite or airplane, we figure out what an object is by the way it reflects "light"
- What are dot density maps used for?
- Dot density maps are used to display count data (raw numbers).
- In the Okavangu Delta most of the water is lost through what?
- Evapotranspiration
- What are examples of discreet data?
- Nominal (names) and Ordinal (ranking)
- What does DEM stand for?
- Digital Elevation Model
- GPS Error: Satellite Orbit Position
- This occurs when the position of the satellite is not accurately broadcasted to the GPS receivers. Error in 1-5 meters.
- Why is GIS important?
- • People use geographic information system (GIS) software because they understand that better information leads to better decisions. A GIS helps create better information by storing data about real-world objects in a database and dynamically linking database to an onscreen map. Linking the database to the map allows you to quickly see geographic features and display them using different information from the database.
- Define ISPY.
- I = Imagery (a picture with data behind it); S = Signature (a unique identifier), P = perspective (what is the view of the image?), Y = YOU (computers and data need people to interpret conclusions)!
- Why are scale bars superior to ratios?
- When an image is blown up or reduced in size, the ratio is no longer correct and must be updated. With scale bars, changes in size are not an issue as the bar updates itself and maintains accuracy.
- What are the methods of capturing data?
- Data can be captured in the field (in situ), remotely , or by using GPS.
- Why is Optical Sensor Technology called passive?
- Using this technology measures sunlight that bounces off of the earth's surface, not actively sending out lasers (LIDAR).
- Describe the "quantile" way of displaying continuous data.
- This splits data into user-specified numbers of classes of varied width. Each class has an equal number of observations.
- What is a choropleth map and what is it used for?
- Choropleth maps are among the most common maps. They look like specific areas divided by polygons and can be separated by colors. These are used to map categorical and quantitative data spatially distributed within each polygon or shape.
- What is a problem associated with choropleth maps?
- MAUP: Modifiable Areal Unit Problem; choropleth maps work on the assumption that mapped phenomena are uniformly distributed equally within each polygon, which frequently is not the case (spatial heterogenality [unevenness] and all the polygons are not the same shape)
- GPS Error: Atmospheric Delay
- The atmosphere bends the signal and throws off the time it takes for the signal to get to us and produces error up to 30 meters.
- Why is vegetation red on satellite images?
- Vegetation reflects near-infrared light, not visible light. Healthy green vegetation looks bright red.
- How do you make Cyan (additive color theory)?
- Blue + Green
- GPS Error: Multipath Interference
- This occurs when the satellite signal bounces off things around you (trees, buildings, mountains) before it hits your receiver. Error up to 1 meter.
- What are the different characteristics that we consider when interpreting remotely sensed imagery (7)?
- Color, Shape, Size, Texture, Proximity, Brightness, Association
- What is the NADIR/orthoganal view of something?
- Looking at an object straight down, from a 90 degree angle. This is ideal in remote sensing.
- What is an example of when the GIS satellites were retasked?
- Desert Storm
- Describe the "natural breaks" way of displaying continuous data.
- This splits data into classes based on natural breaks in trends with the goal of maximizing interclass variation and minimizing intraclass variation.
- What are the general tips for good map making?
- A) Less is more (simplicity rules) B) Include things only when there is reason to include them C) Consider the final medium (is this map going in a book, on a slide, or on the internet?) D) Think of the reduction factor E) Make sure symbols and text are legible and sharply delineated
- GPS Error: Clock Rounding
- Occurs when a satellite sends a number that is accurate to 9 decimal places but your device only displays 4. Since time and position are rounded, there is an error of 1-10 meters.
- What do glacial deposits do to the appearance of water?
- Glacial deposits make water appear milky.
- What is pycnocline?
- A difference in density, seen through suspended sediment, differences in salinity or differences in temperature.
- What are examples of analyzing data?
- Proximity buffer analysis (how far is something from something else); overlay site suitability locations (stacking up layers to look at associations); Network analysis (tracing routes along a network)