Cartegraphic Representation Flashcards
Lecture 5
What is cartography?
the study, art and practice of making maps.
A representation, to scale and on a flat medium,
of a selection of material or abstract features on
the surface of the Earth.
is a method of modelling reality to communicate
spatial information effectively.
What is the cartographic process?
the map making process
Reality > technology > map > user
What is a map?
simplified representation of spatial features or spatial
phenomena on the earth’s surface.
communicate spatial information visually and they are a universal medium for communication of geospatial information.
What makes a good map?
Designed well and communicates spatial information effectively.
a poor map distorts the communication of spatial information.
What is map design?
The process of developing a visual plan to achive a maps purpose.
primary component of cartographic process.
What is cartographic representation?
Representation of real life thing using symbols.
Visual variables show the attributes of map sysmbols.
What are visual variables?
Size
Texture
Shape
Pattern
Colour/ hue
Value
Chroma
What are map symbols used to indicate?
The location of a spatial
feature on a map while visual variables indicate the attributes associated with map symbols.
What are the groups of map symbols?
- Symbols by relationship - intuitively suggest general kinds of data.
- Symbols by resemblance - look like particular data or concepts.
- Symbols by convention - symbols “make sense” even tho they dont really make sense.
Different types of map symbols accommodate different types of
data:
- Are your data at points, along lines, or in areas?
- Are your data qualitative (different types) or quantitative (vary in number)?
- Do you have individual data values, or are they grouped (aggregated)?
What is quanlitative data?
Not associated with numbers (Nominal):
√ house location
√ border or boundary
√ land vs. water
√ animal species
√ plant types
√ political affiliation
What is quantitative data?
– Nominal
categories
√ no rank
– Ordinal relative
√ high/medium/low
– Interval measurable no absolute zero
√ temperature (F or C)
– Ratio measurable absolute zero
√ population in countries
√ temperature Kelvin
What are maps classified by?
function and symbolization
What is a reference map?
General purpose. Serve as base maps, e.g.
topographic maps.
What is a thematic map?
Special purpose. Emphasis on single “theme“.
* Qualitative maps — Different types of data, e.g. vegetation types
* Quantitative maps — Ranked data, e.g. population data
- One topic i.e. theme
- On a base map
- Base map gives spatial context
- Scheme for symbolization
Map can be split into qualitative and quantitative maps
Quantitative maps consist of:
- Dot
- Choropleth
- Graduated symbol
- Pie Chart
- flow
- Isarithmic
What is a base map?
- Provide the underlying geography for creating
thematic maps - Outline maps are a type of base map
What is a topographic map?
shape and elevation of terrain
What is map typography?
is treated as a map symbol
* Has many type variations
* Typography is perhaps the most important map element when legibility is considered
* Used to create pleasing and coherent maps
* sans serif and serif fonts
What is font?
- Complete set of all variants of a given typeface
- Type varies in Size & Colour
What is type size?
Type Size
* Points - a printer’s measurement of type height
* 72 points to the inch
* Measured from lowest point of the descender (p, q, g, y) to the highest
point of the ascender (t, d, b, f)
What is type colour?
- Main color plus variants of shadow, halo, fill pattern
- Rule of Thumb:
- Use bold, bright colors for small letters for maximum contrast
between letter and its background; avoid using pastel colors for
lettering
What is legibility?
- Check all areas of map
What is harmony?
- Limit type choices to one or two typefaces
- San serif on the map & serif for title & legend
What is convention?
- Italic for natural features & upright for cultural features
What to consider for text placement?
- When considering text placement we must recognize two types of
text elements also called labels - Labels are directly associated with feature locations
- Labels are names of features but may also represent an attribute
value - Placement of other text elements (title, legend, etc.) are related to
overall map layout. - Some rules of thumb,
- Place name above and to the right of point symbol (if space
permits) - Line symbols - label should be parallel to the symbol
- Area symbols - label should show extent of the feature
- Align labels either with map border or with lines of latitude
- Place labels either totally on land or on water
- Avoid clutter
- Automated
- Problems of legibility, overlap, clarity in identification of feature
- Must follow cartographic convention
- Problems worsen at small scales
- ArcGIS offers:
- Interactive labelling - one feature at a time
- Converting labels to text elements
- Dynamic labelling - simultaneously label all features of a given class
What are the 3 steps in map design?
- Visual hierarchy
- Map Layout
(planar organization of visual elements)
* Map Size, Orientation Scale, Content
* Map elements
* Design - Map Production
What is visual heirarchy?
- Visual hierarchy is created by placing map elements at different
visual levels according to importance. - I.e. On a map the name of a city will be larger than that of a town
because of its relative importance. - Important features are to be emphasized
What is map layout?
- With regards to size, first ask yourself these questions:
- What does the end user want or need?
- Output limitations: Can you physically produce the desired size?
- Are there publishing, framing, or laminating restrictions or
limitations? - Will the data be legible or useful at the desired size?
- Normally we go for smallest feasible size
What are the map elements?
- Title/Subtitle
- Legend
- Scale Bar
- Date
- North Arrow
- Place Names and
Labeling - Map Symbols
- Borders and Neatlines
- Graticules and Grids
- Inset Map
- Credit Note
- Logo
What is the Map title?
- Provides description of spatial feature/phenomena and normally
the study area - Important map element
- Type size 2-3 X type on map
- Subtitle (smaller) for
- Longer titles
- Complex map subjects
Wha is the Legend?
- The objects on a map are represented using symbols.
- A symbol is a picture on the map that represents something in the
real world. - The Map-key usually show a small picture of each of the symbols
used on the map, along with a written description of the meaning
of each of these symbols.
What is Scale?
- Ratio scale
* 1:50 000 or 1/50 000 - Verbal scale
1cm equals 50 000 kilometers
* Graphic or Bar scale
* Visual scales are more intuitive
* Visual scale will remain accurate even if scaled
Wha is Explanatory text?
- Map content
- Broader context
- Cartographer’s goals
- Interpretation of map patterns
- Purpose = Communicate intent
What are Sources and credits?
- Each map should include:
- Data source(s)
- Map maker, and when made
- Map projection and coordinate system information
What is the North Arrow?
- The North Arrow is a directional Indicator
- Avoid large & complex N-Arrows
- Include especially for
- Maps not oriented north
- Map area unfamiliar to intended audience
What are graticules and grids?
- Often omitted from thematic map
- Include if locational information is crucial to map’s purpose
- Treated as background or secondary information
- Grids display across the body of the map
What are borders and neat lines?
- Borders and Neat-lines - Both optional
- Borders can serve to restrain eye movement
- Neat-lines are finer lines than borders
- drawn inside borders
- part of the graticule
- used mostly for decoration.
What is visual balance?
- After placing the focal element the reader should be directed to the
rest of the map elements in an ordered fashion. - Visual balance results from two major factors: weight and direction.
- Visual weight depends on size & location.
- An object in the upper part of a composition is heavier than one in
the lower part. - Objects on the right heavier
Soft copy maps
Map Production
- exported to Internet
- projected
- exported to other software
- further processed for publishing
- Complex topic
- Color matching between computer screen and printed map not always
exact
How can data be displayed?
Map production
Data Display
* CRT (cathode ray tube)
* LCD (liquid crystal display)
* RGB color model (red-green-blue)
What are the different colour models, and how does it relate to map production?
- HSV color model (hue, value, chroma/saturation)
- CMYK color model (cyan, magenta, yellow plus black)
- Color printers produce dots of ink in place of pixels on computer screen
- Printers translate from RGB (monitor) to CMYK (inks in printer)
- No exact translation, so variations in colour will occur– NB print a test
page…!
