Quze2,3 Flashcards
(23 cards)
What the Typical DTM applications include:
(1) Contour Line Generation
(2) Volume computations
(3) Surfaces Differencing
(4) Surfaces combination
(6) Orthophoto Generation
What the Types of Contour lines Generation
Types of Contour Lines:
1. Intermediate: Main contour lines drawn at regular intervals.
2. Index: Thicker lines shown after every 4 intermediate lines.
3. Supplementary: Finer lines drawn at half-intervals when needed.
Orthophoto Generation In general, there are 2 types of rectification:
(a) Direct Rectification.
Direct Rectification:
Converts image (x, y) to DTM (X, Y) coordinates.
(b) Indirect Rectification.
Converts DTM (X, Y) to image (x, y) coordinates.
What the Data Visualization
Visualization addresses two objectives:
Visualization addresses two objectives:
• Interactive: For exploration, calibration, and refinement.
• Static: For communicating results.
Visualization Techniques Include:
Static visualization
1.1. Contours generation
1.2. Display images
1.3. Shaded relief DTM images
Dynamic visualization
2.1. Spatio-temporal animation
2.2. Non-temporal animation
3.Interactive visualization
3.1. Web-based
What the Static Visualization DTM Derivatives?
(a) Slope Maps.
showing the rate of change
(b) Aspect Maps.
orientation of each grid cell in space
(c) Curvature Maps.
describing the curvature of the terrain in terms
Dynamic Visualization (Animation)
Spatio-temporal animations
Change in space
Change in position
Change in attribute
GIS Definition:
A system of hardware, software, and data for capturing, managing, analyzing, and displaying geographic information (ESRI).
INTERDISCIPLINARITY OF GIS
1.Hydrography
2.Cartography
3.Geography
4.Surveying/ Geodesy / GPS
5.Mathematics
6.Users’ communities
7.Information Technology
8.Remote Sensing/ Photogrammetry
What the GEOGRAPHICS DATA AND INFORMATION
Location – Spatial data
Attribute data
Relationship
Time
GEOGRAPHIC VS GEOSPATIAL
‘Geographic’ refers to the Earth’s coordinate systems
■ ‘Spatial’ refers to any coordinate reference system
■ ‘Spatial’ is more general that ‘geographic’
What the Maps
And A map portrays 3 kinds of information about geographic
Maps:
Traditional tool to store and show geographic info using symbols.
Maps show:
• Location & extent of features
• Attributes (feature details)
• Relationships between features
What the TYPE OF MAPS and definition
Topographic Maps and Thematic Maps:
Topographic Map:
A reference map showing natural and man-made feature outlines.
Thematic Map:
Used to show geographic concepts like population, climate, land use, and movement.
CHARACTERISTICS OF MAPS
Map Scale & Resolution:
• Scale: Ratio of map distance to real-world distance.
• Resolution: Smallest feature size that can be represented.
Projection:
Turns Earth’s curve into a flat map.
Cartographic Abstraction:
Selection
Classification of selected features into groups
simplification of features
BASIC CONCEPT OF A GIS
GIS Evolved from digital mapping for managing, analyzing, and sharing geographic data.
What GIS WORKFLOW
Real World
Data Sources
Users
Data Management
Analysis
What the BASIC FUNCTIONS OF A GIS
Data input
Data storage and management
Processing
Visualization
Decision Support
What COMPONENTS OF A GIS
Data
■ People
■ Methods
■ Hardware
■ Software
What the Data
Spatial data
Non-Spatial data
Data relationships
Temporal
Metadata
What SPATIAL DATA
■ Location-based features or entities.
□ (Latitude, Longitude) coordinates
□ (X,Y, (Z)) coordinates
□ Street address
□ Administrative unit
What ATTRIBUTE DATA
■ Data that are linked to the spatial features
What the METHODOLOGY AND PEOPLE
■ Methodology
□ GIS expertise and knowledge
■ People
□ Problem solving skills
□ Team skills
□ Communication skills
□ Management skills
HOW DOES A GIS WORK?
STEP 1
Data Collection
Data Assembly
STEP 2
Data Analysis
STEP 3
Data Integration
Data Display
