Data Structures and Data Formats Flashcards
________ graphics are comprised of vertices and paths
Vector
What are the three basic symbol types
Points, Lines, Polygons
Points as XY Coordinates
- Are simply XY coordinates
- Generally are ________ and ________ with a spatial reference frame
- When features are too small to be represented as polygons, points are used
(Two answers)
Latitude, Longitude
Lines Connect Vertices
- Connect each vertex with ________
- Usually represent features that are linear in nature such as rivers, roads, and pipelines, among others
- Networks are line data sets that are topologically connected and consist of junctions and turns with connectivity
Paths
Polygons Connect Vertices and Closes It
- Set of vertices is joined in a particular order and closes it
- The first and last coordinate pair are the same
- Use ________ to show boundaries and they all have an area
Polygons
Definitions (Vector GIS Formats)
- Most common geospatial file type in
- All commercial and open source GIS software becomes the industry standard
SHP (Shapefile)
Definitions (Vector GIS Formats)
- Is an XML-based and is primarily used for Google Earth
- The longitude and latitude components (decimal degrees) are defined by the World Geodetic System of 1984 (WGS84)
KMZ/KML (Keyhole Markup Language)
Definitions (Vector GIS Formats)
- ESRI created it to be a container for storing
- Multiple attribute tables, vector and raster datasets
- Offers structural and performance advantages
- Has 1TB file storage
- Within a geodatabase, shapefiles are referred to as feature classes
GDB (File Geodatabase)
Definitions (Vector GIS Formats)
- Manages multiple attribute tables, vectors and raster datasets
- Is a Microsoft Access-based personal GDB
- Has 2GB file storage
MDB (Personal Geodatabase)
Definitions (Vector GIS Formats)
- Are used for displaying a set of symbology in a map
- It doesn’t contain the geographic data itself, is simply specifies how data will be displayed
- Can represent polygons, polylines, points or raster datasets
LYR (Layer)
Definitions (Vector GIS Formats)
- Is the largest crowdsourcing GIS data project on Earth
- OSM is an XML-based file format and the more efficient, smaller PBF (Protocolbuffer Binary Format) is an alternative to the XML-based format
- Data interoperability in QGIS can load native OSM files
OSM (OpenStreetMap)
Definitions (Vector GIS Formats)
- Mostly used for web-based mapping
- Stores coordinates as text in JavaScript Object Notation
- Includes vector points, lines and polygons as well as tabular information
GeoJSON (Geographic JavaScript Object Notation)
Definitions (Vector GIS Formats)
- Is an XML schema that describes waypoints, tracks and routes captured from a GPS receiver
- Minimum requirements include latitude and longitude coordinates
- Optionally stores location properties including time, elevation, and geoid height, among others
GPX (GPS eXchange Format)
Definitions (Data Structures)
- Made up of pixels (also referred to as grid cells)
- Usually regularly spaced and square
- Look pixelated because each pixel has its own value or class
Raster
What type of Raster has grid cells with gradual changing data (e.g. digital elevation model or DEM, temperature)?
Continuous Raster
What type of raster has distinct themes or categories (e.g. land cover)
Discrete Raster
Composition of a Raster Dataset
Raster dataset is made up of cells or ________ (picture elements)
Pixels
Composition of a Raster Dataset
Each ________ is a square that represents a specific portion of an area
Cell
Definitions (Multi-Temporal GIS Formats)
- Is an interface for array-oriented data for storing multi-dimensional variables
- Example could be temperature, precipitation or wind speed over time
- Commonly used for scientific data involved in the oceanic and atmospheric community as a GIS data storage format
NetCDF (Network Common Data Form)
Definitions (Multi-Temporal GIS Formats)
- Commonly used in meteorology to store historical and forecast weather data
- Has advantages of self-description, flexibility and expandability
- GRIB is standardized by the World Meteorological Organization and in operation since 1985
GRIB (GRIdded Binary or General Regularly-distributed Information in Binary Form)
Definitions (Multi-Temporal GIS Formats)
- Designed by the National Center for Supercomputing Applications (NCSA) to manage extremely large and complex scientific data
- A versatile data model with no limit on the number of size of data objects in the collection
- ArcGIS is capable of reading HDF4 and HDF5 data
HDF (Hierarchical Data Format)
Composition of a Raster Dataset
If a cell is assigned the ________ (Null) value, then either no information or insufficient information about the particular characteristics of the location the cell represents is available
NoData
Composition of a Raster Dataset
Cells are arranged in rows and columns, an arrangement that produces a ________ matrix
Cartesian
Composition of a Raster Dataset
Any two or more cells with the same value belong to the same ________ (can consist of cells that are connected, disconnected or both)
(Hint: Starts with Z)
Zone
Composition of a Raster Dataset
Each group of connected cells in a zone is considered a ________
Region
What are the six Raster GIS Formats?
- ESRI Grid
- GeoTIFF (Geographic Tagged Image File Format)
- JPEG 2000 (Joint Photographic Experts Group)
- ASCII (American Standard Code for Information Interchange)
- IMG (ERDAS Imagine)
- BIL, BIP, & BSQ (ENVI Raw Raster)
