Cartography, Digital Mapping and GIS - Year 1 - Lectures 1 to 7 Flashcards
Define cartography
Discipline dealing with the conception, production, dissemination and study of maps in all forms.
What is the Darwinian view of map making?
Map making improves as civilization progresses – focus on accuracy and technology
What is the ‘Old is beautiful’ view of map making?
Art historian perspective, valued for artistic quality
What is the ‘Nationalistic’ view of map making?
cartographic traditions in individual countries
What are other approaches to study the history of cartography?
– The use of maps as documents to communicate specific messages
– The use of maps in their wider societal context (tools of oppression, governance) -> propaganda maps
– The history of the technology required to produce and disseminate maps
– The artistic representation on the map face -> iconography
What was the function/characteristics of early maps?
- focus on local areas
- Make sense of the world around us
- 6200 BC wall painting in Catal Hoyuk (Anatolia, Turkey) -> first map?
- Religious beliefs shaped maps -> small scale (600 BC Babylonian map of the world -> Babylonians saw themselves at the centre of the world)
Define world view
A person’s world view is the way they see and understand the world, especially regarding issues such as politics, philosophy, and religion. Regarding map making people’s world view influences this, e.g. centring your country on the world map
Define indigenous cartographies
The mapping practices, past and present, produced or conceptualised by indigenous peoples and informed by the aesthetics and sign systems of the societies from which they derive. E.g. In Siberia, Chukchi and Mansi navigational cartography is inscribed on bark or painted directly on trees along a route.
What was the emphasis of map making on for the Greeks and Romans?
The emphasis was on practicality. The maps were used for travel and the military
What is the Medieval mappae mundi?
Maps about how the world was seen from a Christian view in the past.
What are Renaissance cartographies?
During the renaissance period, Europeans especially grew more interested in understanding their world, and the fields of geography and cartography gained new prominence. The rediscovery of the work of an Ancient Greek scholars helped both geography and cartography take huge steps forward during this period.
During the renaissance period what was developed that led to maps being made easier and in larger numbers?
The printing press
What is Mercator’s World map?
It was the first 3D map which made navigation by ship much easier.
Why is Mercator’s World map inaccurate?
It exaggerates the size of Europe due to its influence on trade.
Define colonialism
The practice of establishing territorial dominion over another country by an outside political power making it your colony. It involves the controlling country occupying it with settlers and exploiting it for resources.
Define imperialism
A policy of extending a country’s power and influence through colonisation.
What are these the characteristics of?
• Observation-based, scientific approach to data collection
• First developed in 18th century France
• Field-surveying techniques, refinement of triangulation, improved mathematical methods, new methods of relief representation
• increasing use of maps by the state for political purposes (e.g. national mapping projects)
Modern maps
What is cadastral mapping?
A map that shows the extent, value and ownership of land.
What is the last step in the history of mapping?
Digital mapping
What is a topographic map?
A type of map characterised by large-scale detail and quantitative representation of relief, usually using contour lines.
What was the quantitative revolution?
The computerisation of geography which occurred in the 1950/60’s.
How do the terms paradigmatic and ideographic relate to the quantitative revolution?
Ideographic is something that uses a symbol to describe it without a word or sound whereas as paradigmatic refers to using words to describe something. During the quantitative revolution there was an increase in the use of symbols over text in map making (increase in ideographic over paradigmatic)
What is computer-assisted mapping?
any mapping procedure done with the aid of computers
What are these the benefits of? – Reducing costs of map production – Shortening the time of map creation – Dealing with large quantities of data – Reproducing maps of the same quality
Computer-assisted mapping
What are these types of?
SYMAP, line printer, line plotter, desktop mapping, web mapping
Computer-assisted mapping
What is this a definition of?
Using a desktop computer to perform digital mapping functions
Desktop Mapping
What is this a definition of?
An impact printer which makes use of a continuous feed of paper and prints one line of text at a time.
Line Printer
What is this a definition of?
A printer that interprets commands from a computer to make line drawings on paper with one or more automated pens.
Line Plotter
What is this a definition of?
A map that integrates multiple layers of geographic data within a single web application.
Web mapping
Define mainframe
A large high-speed computer, especially one supporting numerous workstations or peripherals.
What is this a definition of?
An organised collection of computer hardware, software, and geographic data designed to efficiently capture, store, update, manipulate, and display all forms of geographically referenced information
Geographic Information System (GIS)
What is this a definition of?
The machines, wiring, and other physical components of a computer or other electronic system
Hardware
What is this a definition of?
The programs and other operating information used by a computer.
Software
What is this a definition of?
The programmers, systems analysts, operating staff, and other personnel working in a computer system
Liveware
What is this a definition of?
Information that can be stored and used by a computer program
Data
What is this a definition of?
A suite of computer programs that together provide the necessary functions for the maintenance of information stored in a computer system.
Database management system
What is this a definition of?
The process of changing data to make it easier to read or be more organized.
Data manipulation
What is this a definition of?
The representation of an object, situation, or set of information as a chart or other image.
Visualisation
How can you spatially manipulate the data of a map?
Change the projections and scales
How can you analyse a map spatially?
- Quantitative analysis - is the data accurate
- Exploratory spatial analysis - a collection of techniques to describe and visualise spatial distributions; identify spatial outliers and discover patterns of spatial association
- Qualitative analysis - does the map look correct
How can data be visualised?
- Maps
- Tables, graphs etc.
- Animations
- Virtual landscapes
According to Robison et al, what are the four components of GIS?
- Hardware
- Software
- People or “Liveware” (Map maker)
- Data
What are these the characteristics of?
• Tell us where a feature is
• Refer to location and dimensions
• Co-ordinate based
Spatial data
What are the 2 methods of representing geographic data digitally (two types of spatial data)?
o Vector data (lines)
o Raster data (pixels)
What are the characteristics of raster data?
- Representation of the world as a surface divided into a regular grid of (usually square) cells
- Properties (attributes) are assigned to cells
- Cells are called pixels: picture elements
- Varying spatial resolution (length of a cell side as measured on the ground) – the higher the resolution, the smaller the pixels
- Each cell is given a single value
- Detail about variation within cells is lost
- Useful for storing data that varies continuously (e.g. aerial photograph, satellite image, elevation surface)
What are the methods of capturing raster data?
o Remote-sensing satellites
o Scanning
What are the two types of data?
Spatial and attribute
What does the method scanning involve?
- Map is scanned in narrow contiguous bands
- Sensor registers light intensity or colour value of small squares
- Measurements are transformed into digital values
- Reconstitution of original colours
What is vector data?
Representation of the world using points, lines and polygons
What are these the characteristics of?
•Lines are captured as points connected by straight lines
•Areas (polygons) are captured as a series of points (vertices) -> start and end point needs to be the same coordinate
Vector data
What is more accurate, raster or vector?
Vector
What is vaster, raster or vector?
Raster
Which type of data is useful for storing data that have discrete boundaries (e.g. country borders, land parcels, streets)?
Vector
What is the digitising method of capturing vector data?
- Converting analogue into digital vector data
- Heads-up digitising - Combination of scanning and digitising. Map is scanned first and displayed and enlarged on monitor. Follow/trace and enter with the cursor the relevant lines or point locations on the screen
What are the potential errors of digitising?
- Double line
- Missing line
- Overshoot/undershoot – polygons (start and end point not the same)
- Missing label
- Spike
What is georeferencing?
The internal coordinate system of a map or aerial photo image can be related to a ground system of geographic coordinates.
What is attribute data?
• Tabular and/or textual data describing the characteristics of map features • Tell us what a feature is – Statistics (census) – Text – Images – Sound
Is raster data used more for human or physical geography?
Physical
What are boundary files and what are the types?
There are two types of boundary files: cartographic and digital. Cartographic boundary files portray the geographic areas using only the major land mass e.g. the land mass of Canada and its coastal islands. Digital boundary files portray the full extent of the geographic areas, including the coastal water area.
What are these the characteristics of?
– Show the locations of a variety of different features (e.g. water bodies, coastlines, roads, vegetation)
– Multiple layers of information
Topographic maps
What type of map do these features describe?
– Special purpose maps
– Concentrate on the distribution of a single attribute or the relationship among several
– Portray the variation within a class of features
– One layer of information
Thematic map
What are the 4 methods to make a thematic map?
- Choropleth (most common and easy to interpret
- Isopleth
- Proportional symbol
- Dot
What are ‘moral statistics’?
Most narrowly refers to numerical data generally considered to be indicative of social pathology in groups of people, e.g. education, crime, pauperism, ‘improvident marriages’ etc.
Why do the boundaries between topographic and thematic maps grow less relevant in a digital environment?
Individual layers (thematic) which when put together form a topographic map.
What type of technique for making a thematic map does this describe?
A map in which enumeration units (or data collection units) are shaded with an intensity proportional to the data values associated with those units (e.g., census tracts shaded with grey tones with an intensity that is proportional to population density)
Choropleth map
How do you know if a choropleth map would be suitable for the data set?
– If spatial variation of observed phenomenon varies with administrative units
– Similar size and shape of administrative units
How do you standardise data to account for different sizes (e.g. different number of people)?
– Divide two area-based raw totals (e.g. number of divorced/number of married)
– Calculate a rate (e.g. number of suicides per 100,000)
– Calculate a summary numerical measure (e.g. median)
– Easiest is by percentages
How do you select a number of classes?
Too few classes: – Little variation, no clear patterns – Data distribution not adequately reflected Too many classes: – Difficult to differentiate Max number depends on: – data distribution – use of grey-tones (less) or colours (more)
What are the types of classification methods?
- Natural break
- Quantile
- Equal intervals
- Standard deviation
- Unique
What are the characteristics of the natural break method of classification?
• Looks for groupings in the data
– minimizes variation within each class
– identifies ‘big jumps’ in the values
• Values within a class are likely to be similar
• Good for data that are not evenly distributed
• Difficult to compare different maps
• Difficult to choose appropriate number of classes
What are the characteristics of the quantile method of classification?
• Equal number of observations in each class (first 10 go in the first class, next 10 go in the next class, etc)
• Good for evenly distributed data
• Emphasises the relative position (e.g. which counties are in the top 20 percent)
However:
- Features with similar values may end up in different classes, esp. if values cluster Or a few wide ranging adjacent values may end up in the same class
What are the characteristics of the equal interval method of classification?
- Each class has an equal range of values
- The difference between the high and low value is the same for each class
- Easy to interpret
- Good for mapping continous data; no gaps or missing values in classification
- Good for comparison of a series of maps
- Inappropriate if values are clustered: there may be many features in one or two classes and some classes with no features
What are the characteristics of the standard deviation method of classification?
- Each class is defined by its distance from the mean value of all features
- Good for displaying features above or below an average value
- Good when the distribution is normal
- But: Does not show actual values of features, only their distance from the mean
- Very high or low values can skew the mean so that most features will fall into the same class
What are the characteristics of the unique method of classification?
- Class boundaries set in accordance with external criteria
- E.g. state requirements; specific criteria set by researcher
- Requires an understanding of the broader context of the data
What are the three dimensions of colour perception?
- Colour hue
- Colour value
- Colour intensity
What is colour hue?
Refers to the dominant Colour Family of the specific colour we’re looking at. The hues are quantitatively different.
What is the colour value?
The perceived lightness or darkness of a hue. Different values are quantitatively differently.
What is the colour intensity?
The purity of a hue (how washed out or bright it is). Appropriate for binary data.
What is colour perception?
How we see colour which includes the hue, value and intensity.
What are the ways to represent colour? (colour models/specification-systems)
- Predefined systems – by name or code (colour A1002C)
- Perceptual system (user-orientated) – colours the average person can differentiate e.g. Munsell system
- Process systems (hard-ware orientated) – commercial and computer printing: use 3 or 4 colours to create all other colours – CMYK – Cyan, magenta, yellow and black. Computer monitor – red, green and blue (RGB)
What does this describe?
A colour space that specifies colours based on three properties of colour: hue, value, and chroma. It was adopted by the USDA as the official colour system for soil research in the 1930s
Munsell System
What does it mean by ‘colours for perceptual differences’?
The idea that certain people are unable to see the difference between colours, e.g. elderly people or the colour blind. For example:
- Older people often have difficulty viewing blue
- Colour vision impaired often struggle from making the difference between green and red (looks the same)
What does it mean by ‘colours connotations’?
Colour often has a symbolic connotation that influence the reaction of viewers. This is the idea that a person links a particular colour to a feeling or object. E.g.
- Blue = water, cool, positive
- Green = vegetation, lowlands, forests
- Red = warm, important, negative
Define colour schemes in relation to mapping?
The types of colours used on a map.
What are the 4 types of colour schemes?
- sequential
- diverging
- qualitative
- binary
What type of data does this describe?
Variables with no inherent order or ranking sequence.
Nominal data
What type of data does this describe?
A continuous measurement of a linear scale.
Interval data
What type of data does this describe?
Data with a clear mid point and values higher and lower than this mid point.
Bipolar data
Which colour scheme does this describe?
A colour scheme for different categories.
Qualitative scheme
Which colour scheme does this describe?
Allows the emphasis of a quantitative data display to be progressions outward from a critical midpoint of the data range.
Diverging scheme
Which colour scheme does this describe?
Classes are logically arranged from high to low with the colours progressing from light to dark.
Sequential scheme
Which colour scheme does this describe?
Nominal differences that are divided into only two categories.
Binary scheme
What colour scheme do you use for nominal data?
Qualitative scheme
What colour scheme do you use for interval data?
Sequential scheme
What colour scheme do you use for bipolar data?
Diverging scheme
What does the ‘Type’ refer to in cartography? What does it involve?
The characteristics of the of text. This involves:
- Typeface/font (type style)
- Serifs/no serifs
- Type size
- Type weight (Bold/underlining)
- Type form (spacing, upper/lower case, colour)
- Type placement
Should you place the label above or below the symbol?
Above
What are the features of map layout?
- Frame line and neat line
- Mapped area
- Inset
- Title and subtitle
- Legend + legend title should be specific stating how it has been measured
- Data source
- Scale
- Orientation
What are the two forms of point data of proportional symbol mapping?
- True point data – actually measured point locations (e.g. temperature)
- Conceptual data – collected over areas but conceived as being located at points for purposes of symbolisation.
What are the two groups of proportional symbols?
- Geometric symbols
- Pictographic symbols
Why are circles commonly used as proportional symbols?
- Visually stable
- Preferred by users over other symbols
- Conserve map space
- Easy to determine appropriate relations between data and circle size
- Easy to construct
What are geometric symbols?
Circles, squares
What are pictographic symbols?
People, diagrams
What are the three types of proportional symbol scaling?
- Mathematical
- Perceptual
- Range
What is the mathematical scaling of proportional symbol scaling?
- Sizes areas of point symbols in direct proportion to the data
- E.g. If data value is 10x another, the area of a corresponding point symbol will be 10x larger.
- Usually proportional symbol maps are unclassed.
What is the perceptual scaling of proportional symbol scaling?
- Larger symbols are underestimated
- Correction is introduced – larger symbols are made bigger -> no longer mathematical
- All perception used should be identified on the legend
What is the range scaling of proportional symbol scaling?
- Data are grouped into classes
* A single symbol size is used to represent all data into one class.
What do these factors branch onto (what term)?
• Map should be neither too full nor too empty
• Change symbol size in software
• Small symbols – little overlap but difficult to see spatial pattern
• Large symbols – create cluttered map, difficult to read and interpret individual symbols.
Symbol overlap
What does this describe?
A map in which small symbols of uniform size (typically solid circles) are used to emphasise the spatial pattern of a phenomenon
Dot map
What is the Unit value?
The count represented by each dot on a dot map.
What type of mapping does this describe?
- Two attributes are combined on the same thematic map
- Combination of two colour choropleth maps
- Information about regions of homogeneous value combinations
- Clear legend important
Bivariate mapping
What type of mapping does this describe?
More than two attributes are shown, each as a separate map.
Multivariate mapping (small multiple)
What are additive attributes?
Measured in the same units
Part of a larger whole
e.g. percentage of various ethnic groups in population
Can be depicted using pie charts
What are nonadditive attributes?
Measured in dissimilar units
Not part of a larger whole
e.g. percent urban and median income
Different multivariate point symbols available, e.g. Chernoff face
What is Chernoff face?
Distinct facial characteristics are associated with various attributes
