Industry Standards Flashcards
Who are the Geospatial Standards Agencies?
-Open Geospatial Consortium (OGC)
-Federal Geographic Data Committee (FGDC)
-International Standards Organization (ISO)
-Federal Bureau of the Budget
-American National Standards Institute (ANSI)
What is the Open Geospatial Consortium’s (OGC) Mission?
Promote geospatial interoperability by developing international standards.
What are the OGC Standard Formats?
File Formats:
-KML/KMZ
-GML
-OGC and ISO Simple Features
-Geopackage
-GeoTIFF
-LAS
Web Formats:
-Web Feature Service
-Web Map Service
-Web Coverage Service
-Web Map Tile Service
-Web Processing Service
What is a Geopackage?
-Universal file format for geodata, based on SQLite
-Open format
-Supports vector and raster data
-.gpkg extension
What are the National Map Accuracy Standards?
-Published by The Federal Bureau of the Budget
-Applies to all Federal agencies that produce maps
-1:20,000 & larger: 90% of points tested (20 points minimum) must be within 1/30” (Horizontal Accuracy)
-1:20,000 & smaller: 90% of points tested must be within 1/50” (Horizontal Accuracy)
-All scales” 90% of points must be at least 1/2 the contour interval (Vertical Accuracy)
What are the SQL Geometry Types (OGC Geometry Model)?
-Point
-Curve
-Surface
-Linestring
-Line
-Linering (poly outline)
-Polygon
What is the Root Mean Square Error (RMSE)?
-The distance between mapped location and the actual location
-Used to calculate GIS data accuracy
-FGDC requires a minimum of 20 points checked for each dataset.
How do Accuracy and Precision differ?
Accuracy:
-Closeness of the information on a map to the values in the real world (boh geographic and attribute data).
Precision:
-Refers how exact is the description of data. Precise data may be inaccurate, because it may be exactly described but inaccurately gathered.
What are the components of Raster Resolution and Accuracy?
-Spectral: Are cell values the proper value RGB or other wavelengths of light?
-Temporal: Does the raster accurately represent conditions for the time period claimed?
-Spatial: Is the raster in the proper location and does the cell size accurately represent the area modeled?
-Radiometric: Are various features distinguishable from each other?
What is the Spatial Data Transfer Standard?
-An ANSI Standard
-Compare identifiable locations on the map to known locations on the ground, and compute an RMSE
-A minimum of 20 check points shall be tested with a 95% confidence level (RMSE less than or equal to the reported accuracy value)
What are the Metadata Standards used for?
-Exist to facilitate the exchange of metadata
-Set by FGDC and ISO (Primary)
-XML is the recommended file extension
What is mandatory information for Datasets according to the ISO?
Title, Date, Geographic Location, Language, Topic Category, Abstract, Metadata
How do you know if your map meets the National Map Accuracy Standards?
Take the map scale denominator, multiply it by the accuracy fraction, and convert to feet. Do 90% of points (20 minimum) fall within that range?
