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PLAN 2006 Exam - Coggle Diagram

- - - - Survey Techniques
        
        Defining the location of a point in our environment.
        
        Location is relative
        
        Determining new positions with respect to existing reference features.
        
        Measuring. angles & distances from geodetic control points.
      - Aerial Photography
        
        Topographic map compilation
        
        Resource inventories
        
        Large areas in great detail.
      - Remote Sensing
        
        The science of deriving information about the earth from images acquired at a distance.
        
        Methods: aerial photography, radar, satellite imaging.
      - GPS
        
        Global Positioning System:
        
        Satellite-based navigation system
        
        24 orbiting satellites
        
        originally intended for military
        
        Made available to all in the 1980s
        
        Worksin any. weather, anywhere on earth, 24/7.
        
        Satellites circle earth twice a day (7000 miles/hour)
        
        transmit information to earth
        
        GPS receivers use information to calculate location (extremely accurate)
      - Geocoding & Databases
        
        A method of attaching spatial locations to datasets
        
        Often done with addresses
        
        Can be used with any database containing a locational attribute
      - Scanning & Digitizing
        
        Create vector data from images
        
        Hard-copy maps, aerial photographs
        
        Digitizing tables, graphics packages
        
        Scanning & georeferencing
  - - - Must use predefined resolution, efficient for storying dense datasets, deals poorly with linear features, only one attribute value per layer.
      - Types of Raster Data
        
        Thematic Rasters: Represent geographical features or phenomena of discrete or continuous data.
        
        Continous Thematic Rasters
        
        Geographical phenomena that may vary at each location
        
        Every cell could potentially have a unique value: Ex: elevation, Temperature, cell phone signal strenght.
        
        Discrete Thematic Rasters
        
        Categorical data, well-defined boundaries, depending on type it may have. associated values.
        
        Image Rasters: Pictures produced by optical or electronic devices (cameras, satellites, scanners).
        
        Produced from optical or electronic devices.
        
        Typically require interpretation of the data
        
        Made up of cells/pixels
        
        Cells Size
        
        Can be any size you define. Smaller ceells have higher resolution (less. generalization), but the smaller the cell size means larger file size and longer analysis times.
        
        Larger cells have less resolution (more generalization)
    - - Efficient for use and storage of sparse datasets, tends to be more precise / higher resolution, deals well with exact boundaries, processing times can be high with complex datasets.
  - - - Many data sources = data at many different scales, this is common and poses challenge for interpretation & analysis.
  - - - File format is the mechanism of how. data is stored on the computer, it indicates to the system where to look for various pieces of information.
      - Format is important. as not all GIS read all types of formats.
    - - Geographic Information: Where data is located and its shape
      - Attribute inforamtion: additional non-spatial data
      - Display information: How features will display on screen.
    - - ESRI Formats: Shape files (.SHP) - A set of related files that have the same name but different extensions (.shp, .shx, and .dbf)
        
        Advantages: ESRI is the standard so other software knows how to deal with it.
        
        Disadvantages: Size limitations (2Gig), holds only vector data, no topology, only holds simple geometries (points, lines polygons)
      - ESRI Formats: Geodatabase - A mechanism to put many layers or themes into a single file system (File or Personal).
        
        There are 3 kindsL Personal geodatabases. (.mdb), File geodatabase - directory, ArcSDE geodatabases - uses. external RDBMS.
        
        Think of it like a container used. to hold all the colleciton of datasets.
        
        Disadvantages: It. is proprietary format (only ESRI can fully read it).
        
        Advantages: Keeps all of your data together (shapefiles only have 1 dataset. in. it) Size limits. are bigger in file/ArcSDE geodatabases, they can hold both simple and complex. geometries, both rasterand vector. data, and multiple people looking at same data at once, its also faster and better compression then shapefiles.
    - - ESRI Internal Format: Grid, ASCII - needs. to be converted (.TXT, .ASC), other supported formats. = TIFF, JPEG.
  - - - Most accurate representation of the. earth
      - Not practical for most applications due to size, lack of detail, only one side. of the earth is visible at one time.
    - - A. model of the shape of the earth that is approximately the shape of. a sphere (flattened at the poles)
      - The primary use is to locate position (it is a requirement. for position in GIS)
      - One way. to measure the shape of the earth.
    - - Spheroids/ellipsoids can be used to represent the earth. Many. There are many different spheroids/ellipsoids.
      - With coordinate systems, datums specify which spheroid/ellipsoid is being used to model the earth.
    - - A measurement base model of the shape of the earth based on gravitational pull
      - Its primary use is for specifying terrain or other heights.
      - it is one way to estimate the shape of the earth.
      - They do not look perfectly spherical, they have rough surface.
  - - - Used for 3D (sphere or globe), locations define by latitude, and longitude, usually measured in decimal degrees.
        
        Longitude and latitude are angles measured from the earths centre to a point on the earths surface.
        
        Latitude lines are parallel and run east to west and around the earths surface, and measure distances. from. north and south of the equator.
        
        Longitude lines run north and south, around the earths surface and intersect at the poles, measures distances east and west.
        
        Prime Meridian
        
        A line of longitude. designated as 0 degrees east and west, to which all other meridians are referenced. Today the prime meridian runs through the Royal Observatory in Greenwhich England.
    - - Used for 2D (maps), locations defined by X and Y measured from origin (0,0), usually in metres, sometimes feet.
        
        Represent the round earth on a flat surface
        
        Changing from round to flat results in distortion (This is unavoidable)
        
        Every map. has distortion: map of small area - less distortion, map of large area - greater distortion
        
        Choosing a map projection means choosing your distortion: Shape, Area, distance, Direction. Only.a globe can preserve all four
      - Types of Projected Coordinate Systems
        
        Map projection tend to be classified in 2 ways: Shape (how they were created) and properties.
        
        Projected Coordinate System Shape Classes
        
        There are 4 main classes: Cylindrical, Conic, Azimuthal/Planar and other.
        
        Cylindrical Projection
        
        Features: Straight Parallels and meridians that meet at right angles. Good for navigation. If mapping the world in this projection there is significant distortion toward the poles. Best known projection of this type is Mercator.
        
        Conic Projection
        
        Feautres: Parallels are represented as circular arcs. Meridians. are represented as straight radiating lines, Typically used for mid-latitudes (for maps of Canada)
        
        Azimuthal/Planar Projection
        
        Features: Most often used at the poles.
        
        Can be sub-classified depending. on where the perspective is. Gnomonic - from the centre of the earth, Stereographic - from. the opposite pole. Orthographic - from an infinite point in space.
        
        Other Projections
        
        Robinson, Sinusoidal, Bipolar Oblique Conic Conformal
      - Projected Coordinate Systems Property Classes: (4 main classes)
        
        Equal Area: correctly shows the size of a feature.
        
        Conformal: Correctly shows the shape of features (A map can not be both equal area or conformal - it can only be one; or the other; or neither)
        
        Equidistant: Correclty shows distance between two features.
        
        True Direction: Corrcetly shows the direction between two features.
      - Seleciting a Projected Coordinate System
        
        Choosing a map projection: Ask yourself what is the purpose of this map. Decide on a class of projection: tropical region - cylindrical, middle latitude - conic, polar region - azimuthal
    - - Network. of intersecting lines called a graticule
      - Latitude and longitude
      - Measure of angle from earths centre to. a point on the surface
      - Measurement expressed in degrees, minutes, seconds or decimal degrees
      - goal is locational accuracy
    - - Uses grid with an x and y axis
      - latitude and longitude converted. (projected) to planar coordinates.
      - Locations ar emeasured with an x and y value from a point of origin.
      - Goal is accurate analysis (measure distance, caluclate area, shortest distance)
    - - ArcMap has "on-the-fly projection"
      - This method of projection works - as long as your datasets share the same geographic coordinate system. If there. isn;'t misalignment may occur.
- - - - Every feature has an ID, one-to-one relationship between feature, identifier and attribute record.
- - - - Elevation_m = [Elevation_cm] / 100
      - Angle_Layer = cos([Input_layer])
      - Sum_Layer = [Layer1 + Layer2]
      - Slope_Layer = slope([Elevation_Layer], degree)
      - Max_Elev_Value = zonalmax([zone_grid], [Elevation])
- - - - Original map resolutions or land survey sets the resolution (+ or - error) of precisions and accuracy.
      - Other issues with the data include year, and season it is taken from.
    - - Digitizing can result in numerous errors including dangle nodes (unconnected) and sliver polygons.
  - - - Is the degree to which information on a map or in a digital database matches true or accepted values.
      - Is an issue pertaining to the quality of errors contained in a dataset or map.
      - Horizontal and vertical accuracy in GIS databases, geographic position, attribute, conceptual, logical accuracy.
    - - Refers to the level of measurement and exactness of description in a GIS database.
      - Precision locational data may measure position to a fraction of a unit.
      - Even the most precise data may be inaccurate.
- - - - Group of neighbouring municipalities joined together for the purpose of regional planning and managing common servcies *like police or ambulance). A Census Division might correspond to a county, regional municipality, or regional district.
    - - Area that is a municipality or an area that is deemed to be equivalent to a municipality for statistical reporting purposes. Municipal status is defined by laws in effect in each province and territory in Canada.
    - - A small relatively stable geogrpahic unit with an average population of 400 to 700 persons. It is the smallest standard geographic area for which all census data are disseminated.
    - - A block is an area bounded on all sides by roads, and/or boundaries of standard geographic areas. The block is the smallest geographic area for which population and dwellings counts are disseminated.
    - - Cover the entire country, with population between 5000-15000. They are created from existing Dissemination Areas. There are 152 ADA in Nova Scotia.
    - - Area that is small and relatively stable, population less than 10000. Located in large urban centers that must have an urban core population of 50,000 or more.
- - - - Hue: The colour dimension described by different wavelengths of the electromagnetic spectrum; associated with differences in kind (qualitative).
      - Brightness: How bright a colour appears overall.
      - Value: How light or dark a colour appears vs. black and white, Ex: Yellow has the brightest brightness, but the lowest value compared to white.
      - Saturation: Perceived amount of white; single hue progression. Ex: From white to Red.
      - Chroma: For a given hue, the perceived percentage of grey (how washed out it is.).
    - - Additive / subtractive colour models:
        
        RGB - Red, green, blue.
        
        Used on computer screens, televisions, it is additive since to make white you have to add all colours.
        
        CMYK - Cyan, magenta, yellow "black"
        
        Used for printing books, magazines, etc. It's subtractive since to make white you add no colour.
    - - Colour Connotations
      - Simultaneous Contrast
      - Visual Difference
      - Different Viewers
    - - Different qualitative/quantitative data need unique representation, make some things pop and others recede. Helps the viewer organize the elements of an image.
      - Figure: The primary focus of the map or image.
      - Ground: The background, stage on which the figure 'sits'.
      - Creating visual hierarchy
        
        Contrast value/saturation/chroma
        
        Contrast the level of detail = figure, less detail = ground.
        
        Creating edges
        
        Contrast textures
        
        Contrast shape & size
        
        Create layers
    - - Neatline
        
        Defines the area of the cartographic image.
        
        Often corresponds with the golden mean.
        
        May be defined by the publisher or the cartographer.
      - Placement
        
        Also arrangement, composition or layout, starts with the best fit for mapped area. Ex: Chile is long and skinny, so a portrait map would work better.
    - - Points: Keep space around each label, space between the point and label, orientate the label 45 degree angle from the point, never directly in front or behind the point. With linear features keep labels on the same side as point.
      - Areal Features: If inside is not possible, treat as a point. Fill space when possible.
      - Masks: Shapes filled with the predominant background colour when you cannot avoid overlapping labels with complex features. (Called HALOS in ArcGIS).
    - - Typeface and fonts matter, choosing between serif and sans-serif, etc.
      - Size of font
      - Roman, Italics, bold, etc.
      - Conventions: 6pt is the lower limit for most publications, 8-12pt is the most common range for publications, 28-38pt for screens or posters, 2pt difference at small sizes, 3-4pt difference at larger sizes.
- - - - GCP's are "A system of points with known positions, elevations or both. Used as a fixed reference in georeferencing map features, aerial photography, or remotely sensed images."
    - - RMS Error is how far off the actual value is from the predicted value.
      - Residuals are calculated seperately for the X and Y coordinates and then combined are used to calculate RMS error.
      - Acceptable RMS error depends on the size of pixels, scale of data, and accuracy/precision of location.
    - - Shape of the line used to estimate the location of data. Indicates the type of transformations (rotation, translation, skewing of data)
      - 1st Order polynomial requires a minimum of 3 GCP's. 2nd Order polynomial requires a minimum of 6 GCP;s.
- - - - LIDAR outputs
        
        DSM: Digital Surface Model (heights of things on Earth.)
        
        DEM: Digital Elevation Model (True surface of the Earth.
        
        CHM/DHM: Canopy Height Model or Digital Height Model. The heights or residual distance between the ground and the tops of buildings and trees, etc.
        
        CHM is created by subtracting DTM from the DSM.