Cartography
"Future Geodetic Engineer! Cartography - the art and science of map-making. Projections, symbolization, and GIS technology!"
1. Map Projections 🗺️
Converting 3D Earth to 2D maps always involves distortion. Choose wisely!
| Projection | Preserves | Best Use |
|---|---|---|
| Mercator (Conformal) | Angles/Shapes locally | Navigation, web maps |
| Transverse Mercator | Angles along central meridian | UTM zones, topographic maps |
| Lambert Conformal Conic | Angles, shapes | Aeronautical charts, mid-latitudes |
| Equal-Area (Albers) | Area | Thematic maps, land use |
| Equidistant | Distance from center | Radio/seismic maps |
Remember: No projection preserves everything!
Trade-offs: Shape vs Area vs Distance vs Direction
2. UTM Coordinate System 📍
Universal Transverse Mercator
- 60 zones worldwide, each 6° longitude wide
- Central meridian scale factor: 0.9996
- False Easting: 500,000m (central meridian)
- False Northing: 0m (N hemisphere), 10,000,000m (S hemisphere)
Philippines UTM Zones:
Zone 50N: 114°-120°E | Zone 51N: 120°-126°E | Zone 52N: 126°-132°E
3. Map Scale & Generalization 🔍
Map Scale
RF = Map Distance / Ground Distance
- 1:1,000 - Large scale (detail)
- 1:10,000 - Medium scale
- 1:50,000 - Topographic
- 1:250,000 - Small scale (overview)
Generalization
- Selection: What to include/exclude
- Simplification: Reduce detail
- Displacement: Move features apart
- Aggregation: Combine similar features
4. Map Symbolization 🎨
Point Symbols
Represent discrete locations: cities, wells, monuments
Variables: Size, shape, color, orientation
Line Symbols
Represent linear features: roads, rivers, boundaries
Variables: Width, color, pattern (solid, dashed)
Area Symbols
Represent regions: forests, lakes, land parcels
Variables: Color fill, pattern, boundary line
5. GIS Fundamentals 💻
Geographic Information Systems
Data Models:
- Vector: Points, lines, polygons (discrete)
- Raster: Grid cells (continuous)
Analysis Functions:
- Buffer, overlay, spatial join
- Interpolation, network analysis
Common Software:
ArcGIS, QGIS (free), AutoCAD Map, Google Earth Engine
6. Practice Questions 📚
Common Board Exam Questions
Q1: What type of projection is best for a cadastral map?
A: Transverse Mercator (conformal) or equal-area depending on requirements. For PH cadastral, Transverse Mercator (PRS92) is standard.
Q2: If map scale is 1:25,000, what ground distance does 4cm on map represent?
A: 4cm × 25,000 = 100,000cm = 1,000m = 1km
Q3: Manila is at approximately 121°E. Which UTM zone?
A: Zone 51N (covers 120°-126°E)
🔥 GE Challenge 🔥
Master the art of maps! Projections, scales, symbolization, GIS - transform data into visual information!
A good map tells a thousand words!
Test Your Knowledge! 🧠
Ready ka na ba? Take the practice quiz for Cartography to reinforce what you just learned.
Start Practice Quiz 📝