Gr 220 Exam 1

Cartography

The making and study of maps in all their aspects, representing geographical areas on a flat surface.

Importance of Cartography Standards

Standards for cartography are essential for ensuring maps can be read and understood internationally.

Eratosthenes

Ancient Greek scholar who calculated the Earth's circumference using geometry.

Ptolemy's Map

A 2nd century AD map that included latitude and longitude.

Mercator Projection

A type of map projection that preserves local direction and shape but distorts size near the poles.

Thematic Maps

Maps used to show the distribution over space of different types of data, integral to spatial analysis.

Geodesy

The study of the Earth's shape, orientation in space, and gravitational field. The Earth is not a perfect oval or circle, the shape it is is known as a geoid

Datum

A reference from which measurements are made in mapping.

GIS

Geographic Information Science, focusing on the management and analysis of geographic data.

Coordinate System

A system that uses numerical values to define locations on the Earth's surface.

Basic Characteristics of Maps

Maps include location, attributes, reductions, geometrical transformations, and abstractions.

Graphicacy

The ability to read and understand graphical data, including maps.

Spatial Analysis

The process of examining the locations, attributes, and relationships of features in spatial data.

Map Projections

Methods used to represent the curved surface of the Earth on a flat surface, with various types to reduce distortion.

Ellipsoid

A mathematically defined surface that approximates the shape of the Earth.

Geographic Coordinate System

A reference system that uses latitude and longitude to specify locations on the Earth's surface.

Cartographic Representation

The various methods used to visually portray geographical information on maps.

Visual Acuity

The clarity or sharpness of vision, which is enhanced through effective map design.

Color Model

A mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values.

Symbolizing Quantitative Features

Using color and patterns to represent numerical or categorical data on maps. Match color to topic, hue progressions, value progressions, hue guidelines, value guidelines, pattern-value guidelines

Map Scale

The relationship between a distance on the map and the corresponding distance on the ground.

Medieval thinking

The melding of geographical experience with religious teaching = church maps; example: importance of Jerusalem

Renaissance -> Globalism

Needed better tools for more accurate maps (age of exploration), The use of geometry reappeared, and the discipline entered into universities

Enlightenment

The reintroduction of science and precise measurement and thematic maps were introduced to show the distribution over space of different types of data (birth of spatial analysis)

Chronometer

Used for the navigation at sea, can measure/map latitude

Cartographical modeling

susceptibility maps, suitability maps, habitat maps, least cost path maps

susceptibility maps

Shows the susceptibility of an area to a specific disaster

suitability maps

Shows the suitability of an area for crops/forests/species etc.

habitat maps

Shows the habitat of a specific species

least cost path maps

think of it as a map which shows the line of best fit

Technology and Cartography

Manual tech, Magnetic tech, Mechanical tech, Optical tech, Photo-chemical tech, Information age mapping - GIS, Future - virtual reality 

Original GIS

1963 Canada Geographic Information System

Forms of Representation

Graphicacy and graphical representation

Need for maps

extend vision, provide spatial understanding, facilitate navigation and communication

Categories of maps

classed by scale, function and subject

classed by function

general reference maps, thematic maps, and charts

Margin elements

Margin elements are all the non-map items in your map

Primary Elements

Maps, insets, legend, title, subtitle, north arrow, scale bar, date, authorship, page border

secondary elements

neat lines, graticules, network path, disclaimer, data source and citation, logo, graphs, photos, map number, copyright, projection, and descriptive text

what is a font

Font is the design of letter style group: e.g. 12 point italic Futura

Typeface: general category of text: e.g. Futura, Arial, Times Roman

BUT, most people just call it all “Font” these days

Serif

Closer range reading to eliminate confusion of I and L or other similar letters

non-serif

More readable at a distance (posters)

Web maps (usually but not always these days)

Lower resolution situations

Favored fonts

Verdana (san) and Georgia (serif)

General Sizes

Reading body text: 12 -14 pt

Title: 16-20-24 (depending)

Letter spacing

Don’t space out more than 4x the letter height or the features won’t look like they make a word

Red text

important or dangerous, highways

Green text

natural features

Brown and grey/black

natural features, parks, forests, mountain ranges

Nature of color

Product of our mental processing of electromagnetic radiation (EM)

Spectral color

Visual sensation of light occurs because receptors in our eyes are stimulated by EM radiation of certain wavelengths

Hue

the color dimension associated with different dominant wavelengths of EM

Brightness

general term for how light or dark a color appears

Value

sensation of lightness or darkness evoked by a color

Additive color system

Mixing different amounts of RGB (primary colors) creates the secondary colors

Subtractive color system

Begins as white and colors (wavelengths) are ‘’blocked” or filtered from reflecting light back to you

Trichromatic theory

Eyes have red, blue and green wavelength receptors, But this is only true to the extent that our eyes have cones sensitive to blue, green, and red wavelengths

Opponent theory

Electrical impulses from the cones do not travel directly to the brain

Cone cells are connected to three types of ganglion (nerve) cells

BY (blue-yellow)

GR (green-red)

WBK (white-black)

CIE (Commission International de l’Eclairage)

Objective system

Precise specification of any color in numeric terms

Makes use of spectrometers to measure reflectance

Munsell System

3 dimensions of color; hue, chroma and value (think xyz plane)

Natural Color System

whiteness to blackness, color wheel

RGB Color Model

A cube with positions specified as ‘x’, ‘y’, ‘z’

Range of integers defines colors in the cube

0,0,0 = black;

255,255,255 = white

HLS Color Model

Hue, Lightness, Saturation

Double cone – similar to the Natural Color System

Each Hue specified by angular distance from blue

HVC Color Model

Hue, Value, Chroma

Three-dimensional color space identical to Munsell color solid

Visual acuity

the ability to detect and differentiate between small symbols

Single Hue Progression

Value decreases and chroma increases systematically all the colors move from pure white to pure hue

Bi-Polar Progressions

Progression from a one pure hue to another pure hue

Denotes a range of change from a positive to a negative

Center is white

Partial Spectral Hue Progression

Endpoint and mixture hues match part of the solar spectrum

Represent mixing/percentage of two variables in an area

Blended Hue Progression

Use related hues to ‘blend together’ the two end point hues

Value Progression

Used on monochrome maps

From white to black / light to gray

Full-Spectral Progression

Hues from blue through red are used

Easy for map readers to match colors with legend classes

Used in elevation

Two-Variable Color Progression

Two variables, each represented by one hue

Progression within each hue

Hue Guidelines for Quantitative Progressions

Darker = more

Yellow has fewest

Best to use yellow as an endpoint hue in progressions

Value Guidelines for Quantitative Progressions

Greater value contrast among symbols, greater the clarity

Pattern-Value Guidelines for Quantitative Progressions

Regular spaced dots, lines, or cross-hatch can be used to indicated ‘value progressions’

Dots, depending upon spacing, can provide progression of texture

Dot and line patterns have an orientation to viewers

Texture pattern progression

Progression of coarse- to-fine texture dot, parallel line, or cross-hatch can be used to symbolize quantitative texture

geoid

roundish blobby thing) - is the HYPOTHETICAL shape that the ocean surface would take under gravity and rotation alone (no tides or wind) - this shape is extended ‘through’ continents. There are almost an infinite number of geoids

Special color design issues

Color blindness

Type of ellipsoid used

At small scale (continents, regions, countries)?

not much

At medium scale (states / districts / counties)?

sometimes

At large scale (towns, parcels)?

yes

Which ellipsoid is used when creating a datum?

The ellipsoid (spheroid) is used that best fits the geoid at the area where the map is going to be made.

For world maps, an ellipsoid that best fits the whole geoid is used (these are derived from satellite measurements).

For local maps, the ellipsoid that best fits that area is used.

Vertical Datums

Height above Geoid:

mean sea level is no longer used; orthometric heights (height above geoid) is used

What are the six types of projects

• Equal Area projection: preserves area (also equivalent area)

• Conformal projection: preserves shape (preserves angles), but only locally

• Azimuthal projection: preserves direction

• Equidistant projection: preserves distance

• Gnomonic projection: preserves shortest route

• Compromise: preserves neither

UTM

Worldwide

Universal transverse mercator

Both a projection and coordinate system

Tangent along central mendian

Greatest accuracy is the central meridian

State Plane Coordinate System

Each state is divided into one or more zones

Each zone is its own coordinate system (similar to UTM)

East-west zones (horizontal) use Lambert Conformal Conic Projection

North-south (vertical) zones use the Transverse Mercator Projection

Military Grid Reference System (MGRS)

System is an extension of the UTM system. UTM zone number and character are used to identify an area 6 degrees (E-W) and 8 degrees (N-S)

UTM Zone number and designator are followed by 100 km square easting and northing identifiers

The system uses a set of alphabetic characters for the 100 km grid squares

the different data types

- Integer data and floating point data

- Categorical data:

Interval and Ordinal

Numeric data

Ratio data

Ordinal

Natural ordered, Ranked data, first second third, etc.

Interval data

Measured along an equidistant scale

Temp

No natural zero point

Ratio data

There is a natural zero point

Population density

Time

Kelvin temperature scale

Nomial

Named

Can not be defined as ordinal

three projection surfaces

cylindrical, conic, and azimuthal