Week 2: Making maps, data visualisation, and GIS output

ENV208/ENV508 – Applied GIS

Overview

• GIS Output

• Map Making

– Types of Maps

– Key Elements

GIS Output Formats

• Table

• Graph

• Statistics

• Maps

Map Making

• Maps are created to communicate the information present in spatial data to a map-reader

• Goal is to communicate the spatial information portrayed on the map as effectively and efficiently as possible

• Ideally, reading a map is both a pleasing and enlightening experience for the map-reader

• Most popular use of GIS is for making maps

GIS Data Output Methods

1. Monitor display

2. Exporting to a digital file

3. Printing or plotting on paper

GIS Data Output Methods

1. Monitor display

– Take computer and data to client

– Most easily updated

– On the spot modifications

– Cheapest

– Ephemeral

GIS Data Output Methods

2. Exporting to a file – Data in digital format

– Transferred to other computer or software system

– Disc, USB… easily transportable

3. Printing or plotting on paper – Most common

– Generates hardcopy

– Knowledge of cartography desirable

Important Considerations

• Need to be clear about intended audience – Who is the product for?

• Specialist or general public? • Adult or child? • Type and form of presentation? • Scale and accuracy needed?

• Budget constraints

• Technological constraints – Appropriate file format – Delivery mode

Success of GIS is often gauged by quality of the output !

The Cartographic Process

• Cartography

– The science or art of making maps

– Purpose to transmit information, knowledge or location and/or facilitate travel

– Greek.. Chartis (map) and graphein (to write or draw)

– Oldest maps date back to 7-6th century BC

– Thrower, N. J. W. (1999) Maps & Civilization: Cartography in Culture and Society, Chicago: University of Chicago Press, 326 p.

The Cartographic Process

• Cartography – The science or art of making maps

The Cartographic Process

1.Think about what the distribution of the phenomenon might look like

2.Decide on the purpose of the map and the intended audience

3.Collect data that are appropriate for the purpose of the map

4. Design and construct the map using appropriate cartographic principles

5.Determine if the map reader understands the map content

Types of Maps

• Two general map types:

– Reference or formal maps (location, navigation)

– Thematic or transitory (visual display, information analysis)

•Maps contain distortions from:

– Scale

– Projection

– Symbology

Types of Maps

Reference or formal maps

• Depict selected details of the environment as accurately as possible – Road maps, political maps, physical maps, topographic maps

– Location, distance, orientation, reference, known features

Types of Maps

Reference or formal maps

• Depict selected details of the environment as accurately as possible – Road maps, political maps, physical maps, topographic maps

– Location, distance, orientation, reference, known features

8/ 03/ 2015 7:16 pmCharles Darwin University to Darwin NT - Google Maps

Page 1 of 1https:/ / www.google.com.au/ maps/ dir/ Charles+ Darwin+ University,+ E…a0fc9f59043f:0x30217a82a247c20!2m2!1d130.8417772!2d- 12.4628271

Charles Darwin University, Ellengowan Dr Darwin NT

Drive 13.0 km, 16 min

Charles Darwin University, Ellengowan Dr

University E Dr Dripstone Rd

north-west University E Dr

right University E Dr

3rd University E Dr

Bagot Rd National Highway 1 Knuckey St

2nd Dripstone Rd

2nd Lakeside Dr

right Trower Rd

Bagot Rd

right Bagot Rd

National Highway 1

left McMinn St

right Knuckey St

Darwin NT

Map data ©2015 Google

Types of Maps Thematic maps

• Depict the general spatial pattern of selected data or features (e.g. population distribution) – Qualitative (categorical data e.g. soil type) – Quantitative (numerical data e.g. pH values of soil)

• Usually have a base map with a thematic graphical overlay

• Producer includes only the amount of information necessary to convey the map message

• Emphasise a particular feature or set of data – Choropleth maps – Dot-density maps – Proportional symbol maps – Flow maps – Isoline maps – Cartograms

Thematic maps

• Choropleth maps: use colour shading to represent different quantities or values

- From Greek choros (place) and pleth (value) - Use when data occur within well-defined units or are numeric interval data - Involves some method of data classification - Generally derived from values describing attributes of non-overlapping

polygons

Thematic maps

• Choropleth maps: use colour shading to represent different quantities or values

- From Greek choros (place) and pleth (value) - Use when data occur within well-defined units or are numeric interval data - Involves some method of data classification - Generally derived from values describing attributes of non-overlapping

polygons

Thematic maps

• Choropleth maps: use colour shading to represent different quantities or values

www.bom.gov.au

Thematic maps

•Dot-density maps: use points on a map to correspond with occurrence

www.bom.gov.au

• Isoline maps: use lines to connect points of equal value (isotherms for temperature, isohyets for rainfall, contours for elevation)

Thematic maps

Average annual rainfall

Thematic maps • Isoline maps: use lines to connect points of equal value

(isotherms for temperature, isohyets for rainfall, contours for elevation)

Temperature and sea level pressure

•Graduated symbol maps: draw attention to big concentrations of your distribution by varying symbol size to concentration in an area

Thematic maps

Thematic maps • Flow maps: show the origin of some flow/movement between

places, with line width proportional to quantity of movement.

Thematic maps • Cartograms: spatial features are drawn (distorted) in

proportion to the value of an attribute

Thematic maps • Cartograms: spatial features are drawn (distorted) in

proportion to the value of an attribute

Thematic maps • Typographic maps: use typography as line and area map

symbols

Activity

Find an example of each of the following maps: • Reference • Choropleth • Dot-density • Isoline • Graduated symbol

– What data/information layers were necessary to create the map?

– How is it effective in communicating its message

– What audience is the map intended for?

– What do you really like about the map?

– Would you make any adjustments to improve the map?

Keep the maps saved/open for later

http://thelandofmaps.tumblr.com/

Landofmaps.com

Key map elements

Two basic components:

1. The map itself

2. Information about the map (‘marginalia’)

It is completely up to the map maker to decide where

this information is shown on their map

1. The map itself

2. Marginalia

• Title

• Orientation

• Date

• Map Legend/symbols

• Datum/projection

• Scale

• Location

• Grids and Graticules

• Product Information

Marginalia

Title: What is the purpose of the map?

• What is being mapped, where, when?

Marginalia

Orientation: Which direction is north?

• North arrow

• Compass rose

• North is usually pointing towards

the top of a map

N

Marginalia

Date: When the map made (or updated)

Marginalia

Map symbols and Legend: What do the

classes and symbols on the map represent?

• Keep the design of any symbols as

simple and as different from each other

as possible

• Give sufficient information to ensure

your map is not misread

A single tree? A forest? A national park?

Marginalia

Map symbols and Legend: Describe what is on

the map

• Shape – a rectangle for a building, a tree

for a forest

• Size – the larger a feature the higher the

importance of the feature

• Colour – blue for water, green for

vegetation

Map symbolism

Map symbolism has become pretty standardised, so that even foreign maps are not all that hard to read

Map symbols should be readily recognizable and suited to the scale of the map

Three main categories:

• pictorial symbols

• colour symbols

• value symbols

Colour symbolism

• Blue – water features

• Green – vegetation

• Brown – topography or terrain

• Black – human artefacts such as individual buildings, railroads

• Red – larger human artefacts such as highways, roads, urban built-up areas

• Purple – human artefacts since previous map revision

Map symbolism

Map symbolism

• Use existing ‘standard’ symbols/colours if possible

Map symbolism

• Use existing ‘standard’ symbols/colours if possible

Map symbolism

• Use existing ‘standard’ symbols/colours if possible

Map symbolism

• Human limitations

- About 12 colours

- After that use patterns as well

- About 7-8 shades of the same colour

• Colour blindness

• Contrast

• Common sense

Map symbolism

Value symbols - Identify something

- Show it’s location

- Tell something about the amount of that

something in that location

Map types:

- Dot maps

- Graduated symbol maps

- Divided circle map

- Bar chart map

Marginalia

Datum/Projection: The system whereby the information of

the Earth is transferred to a two-dimensional area (a map)

• Often sought by map users, often many years after

the map was published

Map scale: How does distance on the map

relate to distances on the ground?

• Scale statement (e.g. “one cm equals one

kilometre”)

• A ratio or fraction (unitless value)

• A scale bar

Marginalia

• A map without a scale is basically just a diagram or picture

• A small scale map generally shows less

detail but cover larger parts of the earth

• A large scale map is one in which a given

part of the Earth is represented by a

large area on the map (usually show

more detail)

Scale

Marginalia

Location: The location of the map on the Earth

• Draw a recognisable region with an

indication of the mapped location

Marginalia

Grid and Graticules : How to find places on the map

• Alphanumeric grids: Columns are lettered and run down

the page, rows are numbered and run across the page

• Latitude and longitude: geographical coordinates in

degrees, minutes, and seconds

• Cartesian: More useful where the area of interest is a relatively small portion

of the Earth’s surface

Marginalia

Product information:

• Who produced/published the map? (including

organisations, sponsors etc.)

• Date of publication and/or information shown on

the map

• Known limitations of the information (e.g. accuracy)

• Methodology used to produce the map

• Edition (unless it is the first edition)

• Copyright

Generally, too much information is better than too little

Marginalia

Product information:

• Who produced/published the map? (including

organisations, sponsors etc.)

• Date of publication and/or information shown on

the map

• Known limitations of the information

• Methodology used to produce the map

• Edition (unless it is the first edition)

• Copyright

Generally, too much information is better than too little

Key map elements

Two basic components:

1. The map itself

2. Information about the map (‘marginalia’)

It is completely up to the map maker to decide where

this information is shown on their map

Overall layout

• Create final product that is informative, accurate, and aesthetically pleasing

• Visual balance is very important • Map should be centre of display and

have the most visual impact • Exercise in graphic design

• Legibility

• Colour schemes • Use contrast to enhance the

infromation from the background (contextual information)

• Use colour appropriately

Go back to the maps you found earlier and consider the key map elements.

• Title

• Layout

• Orientation

• Date

• Legend/symbology (shape, size, colour)

• Datum/projection

• Colour

• Scale

• Location

• Grids and Graticules

• Product information

Do your maps have all/any of these features?

Would the addition of any of these features help an audience to understand their message?

Activity