MODULE 2A: FUNDAMENTAL CONCEPTS IN MAPPING Flashcards
- Any picture, drawing or group of objects that help understand a place
- A scaled model or reality
Map
mapped records of ambush areas for ancient hunters
Cave paintings
depict physical spatial elements from the community’s POV in 2D
Sketch maps
Elements of a Map
- Scale
- Distance
- Direction
- Location
- Coordinates
- Symbols
- Type of Map
The relationship between a unit of length on a map and the corresponding length on the ground (Usually expressed in a ration (1:100))
Scale
Measurement of how far one point is to another
Distance
can be determined in the map through scale
Ground distance
main tool for measuring direction or bearing
Compass
Physical place where appoint is found on the Earth’s surface
Location
Types of location
- Absolute location
- Relative location
using coordinates (latitude and longitude)
Absolute location
e.g. 3 km northwest of CHE building
Relative location
Pair of numbers that describe a location usually expressed in Degrees, Minutes, Seconds (DMS) format
Coordinates
Legend in the map guides the reader what each symbol, pattern and line means
Symbols
Types of maps
- Topographic Maps (“topo” maps)
- Thematic Maps
shows the shape and features of the land
Topographic Maps (“topo” maps)
made to highlight certain subjects or themes
Thematic Maps
Three fields that focus on mapping
- Cartography
- Geography
- Geodesy
Art and science of graphically representing a geographical area, usually on a flat surface such as a map or chart
Cartography
Study of the Earth and its lands, features, inhabitants and phenomena
Geography
Science of accurately measuring and understanding the Earth’s geometric shape, orientation in space, and gravity field (NOAA)
Geodesy
Geodesy is the science of accurately measuring and understanding the Earth’s __________, ___________, and ___________
- geometric shape
- orientation in space
- gravity field
A known constant surface which can be used to describe the location of unknown points
Reference Datum
By using an ______________ as a datum of the earth, we approximate the shape of the earth fairly well and provide a datum to which all points on the earth can be referenced from
oblate ellipsoid
Universally used reference datum - used by the Global Positioning System (GPS)
WGS 84
WGS 84 is comprised of 4 things:
- Reference Ellipsoid
- Standard Coordinate System
- Vertical Datum (Elevation)
- Horizontal Datum
Other reference systems used in the PH
- Luzon Datum 1911
- Philippine Reference System 1992 (PRS92)
Reference system for the first modern geodetic survey in the PH
Luzon Datum 1911
Homogenous national network of geodetic control points (GCP), marked by concrete monuments (mojons), established using GPS technology
Philippine Reference System 1992 (PRS92)
Coordinate Systems
- Geographic Coordinate System (GCS)
- Projected Coordinate System (PCS)
Uses a 3-dimensional spherical surface to define locations on the earth
Geographic Coordinate System (GCS)
Defined on a flat, 2-dimensional surface which has constant lengths, angles, and areas
Projected Coordinate System (PCS)
x-values
longitude
y-values
latitude
What is the longitude and latitude measured in?
angular degrees
A system which gives the relation between the position of a point on Earth and that of the same point on a map
Map Projections
Map projections aims to transform a part of the Earth’s surface from a globe onto a ________, at the same time keeping distortions in _______, _____ and _______ as small as possible
- plane
- shape, area, and distance
Types of Map Projections
- Cylindrical Projection
- Conical Projection
- Azimuthal or Planar Projection
- Transverse Mercator
Map Projection: Gives true relative projection for countries near the equator; distorted near the poles. Area is preserved.
Cylindrical Projection
Map Projection: Area and distance is distorted especially at the bottom. Scale is preserved.
Conical Projection
Map Projection: Distortion at the four corners of the edges where it is farthest from the globe
Azimuthal or Planar Projection
Capable of mapping a large extent of North-South region with a low amount of distortion (Direction and shapes are correct)
Transverse Mercator
Most used Traverse Mercator
Universal Transverse Mercator (UTM)
Allows precise measurements using meter as a basic unit of measure (universally accepted by the scientific community)
Universal Transverse Mercator (UTM)
