GST 101 Introduction to Geospatial Technology��Unit 4 – Introduction to Cartographic Design�Module 4.1 – Visualizing Geospatial Data����� � �

Ann Johnson

Associate Director

ann@baremt.com

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Based upon work supported by the National Science Foundation under Grants DUE 1304591, DUE 164409, DUE 1700496, DUE 1937177, Due 1938717 DUE 1937237, 2030206 and 2015927. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

National Wildfire Coordinating Group

https://www.nwcg.gov/

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This Module introduces some of the basic concepts for visualization of data using principles from cartography and map design

A thank you to Huge Howard from American River College for use of materials from his

course based on Thematic

Cartography and Visualization text that he has co-authored

This brief introduction should be followed by a full course. See GeoTech Center’s Cartography Design Model Course for an in-depth coverage of cartographic design and the Concept Modules on Color and Data Visualization

Traditional Map Design of Fire Boundaries in Southern California

One Picture is Worth a Thousand Words*

• This quote from early 1900’s suggests why output of a spatial analysis would be much more difficult for most people to understand and act on if it was presented only using words
• Visualization of Geospatial Data Analysis
• Maps, charts, and other graphic elements help the intended audience understand and use the information
• Understanding how to present the data using good cartographic design for the intended audience in an appropriate format are vital
• The History of Cartography https://press.uchicago.edu/books/HOC/index.html provides an in-depth study of the history and development of cartography

*http://en.wikipedia.org/wiki/A_picture_is_worth_a_thousand_words

Map Design

• Ultimately, the map is what distinguishes geospatial technology as a different approach to the management, analysis and communication of spatial information
• Poorly made maps (and even well-made maps) can miscommunicate information
• Each map is just one of all possible maps
• Complex maps can be difficult to understand
• Maps can be created to provide misinformation – How to Lie With Maps by Mark Monmonier is an interesting read on this topic
• http://www.amazon.com/How-Lie-Maps-2nd-Edition/dp/0226534219
• When a map is the result of a complex analytical or modeling process, good cartographic design is essential

�Data Visualizations – Maps, Graphs, Charts, Tables

Four of the Most Important Factors in Creating Data Visualizations – static or interactive are:

• Know your audience
• Know what you want to communicate
• Know your data, and
• Know how it will be delivered – paper or web: static or interactive

Hint: When a visualization is finalized have someone else look at it and make sure it communicates well to the intended audience!

Designing an Effective Map

Based on the need of the audience for the map and the answers to the questions on the previous slides, determine what:

• Colors
• Fonts
• Symbols
• Features to include – the fewest to tell the story
• Map Scale (small, medium or large scale)
• Map Projection (are areas, direction, or shape of features most important)
• Cartographic elements needed to help the audience understand the story

Maps

• Help us see patterns created when data is displayed by its geographic location
• Watch the “25 Maps that will change the way you see the world” on: https://www.youtube.com/watch?v=SXB1Z_CxBK0
• The 25 maps quickly tell a story using shapes (points, lines and areas), a map projection, text and colors appropriate for the viewer of a web map to quickly get an understanding about the topic of the map
• Do they include all of the elements of a traditional map?
• No, but they do meet the needs of the intended audience

Cartography and Cartographic Design

• Digital Cartography is an art, based on science, using technology
• Traditional cartography used for Atlases, Road Maps, and other thematic maps use design elements that helps viewers understand the content. Some element are:
• Scale bars, legends, north arrows, neat lines, inset maps, information about the projection used and date of creation and updates
• Maps must use “appropriate” cartographic design principles for the intended audience!

Which MAY or MAY NOT use the traditional cartographic elements

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Rethinking Cartography

• A traditional “Map” and its essential elements may include:
• Title
• North Arrow
• Scale Bar
• Legend or data description of data
• Neat lines around map elements
• Date, Source, Projection, Datum (Metadata)
• Inset map if needed
• The map on the right has some, of these essential elements – are they all needed?

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Map courtesy Tahoe National Forest on YubaNet.com

It is a is a “static” web map for a specific topic and time period – but where is the Legend?

Map With Legend – But does it help understanding?

• Legends should help viewers understand the important symbols used on the map
• What is the reason for the different size and color of the symbols?
• Legend: Is it important to include what symbols are used for streets, railroads or census place?

Interactive Web Maps

• A specific topic – Weather Alerts
• Focused to a knowledgeable audience
• Does not include traditional

“map elements”

• Can be customized or queried by the user

All Maps Are Generalizations of the Real World

• The quantity of details shown on a map depend on its “scale” and the size of the medium for the map (wall poster, computer screen, etc.)
• Small scale maps show a small amount of detail in a large area
• Global maps showing only continents and major cities
• Continental maps showing boundaries of states and counties
• Large scale maps show a large amount of detail in a small area
• A map of a small town with roads and buildings
• A map of a city block showing details of building, utilities, roads, etc.
• No matter the scale, only features important to communicate the map’s story to the audience should be included

Scale in Geospatial Technology - Historically to the Present

• Scale: how distance on a map relates to distance in the real world
• In the past, maps were paper with unchanging scale usually defined by:
• Bar scale:

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• Ratio: 1:XXXX (1/1000) and/or
• Verbal (1 inch per mile)
• Web maps, accessing data online and mapping applications have changed how users can view and combine data
• Zooming In and Out can change the view, but may or may not change the underlying scale
• Cities as points in small scale maps do not generally change to large scale map detail
• Data created for small scale (global) maps generally do not have enough detail to be validly used at large scale
• Data downloaded from the web should have its metadata and its scale documented

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No Firm Divisions for Terms Used for Scale:

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https://en.wikipedia.org/wiki/Scale_(map)#The_terminology_of_scales

Comparison of Large Scale to Small Scale Maps From Ordnance Survey video

Small Scale

Large Scale

https://www.youtube.com/watch?v=6ov-6UI13es

Scale - Data and Its Collection or Creation

• When data is collected, its scale should be part of its metadata!
• Example on right shows the same

stream created at two different scales

• Blue stream is a very detailed scale with

many vertices defining bends in the stream

• Red stream was collected for use in a small-scale map with bends generalized using fewer vertices

Use of data in projects should be governed by:

• The scale (and detail) level it was created in
• Is it an appropriate map scale for the project

Some Limitations of Paper Maps

• Fixed scale
• Fixed extent
• Static view
• Can get quickly out of date
• Flat and hence generally limited to 2D or visualization techniques used to identify 3D features (shading for elevations)
• Map producer-centric such as road maps by states
• Paper Maps still have value
• They can be folded and fit in a pocket and if the power goes out or your GPS malfunctions, having a paper map can be life saving!

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General Reference vs. Thematic Maps

Represent a wide variety of features, but focus on nothing in particular

Include only features that are directly related to the theme, or a small number of related topics

Examples from Hugh Howard, American River College, Cartography Course

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2D: Reference Maps

• The family of maps that are used to locate features on the surface of the Earth
• Geographic features and map elements on a reference map tend to be treated and represented equally
• The accuracy of a given reference map is critical to many users
• Local governments need accurate reference maps for land use, zoning, and tax purposes
• National governments need accurate reference maps for political, infrastructure, and military purposes

• Many types of thematic map
• Cartogram
• Choropleth
• Dasymetric
• Dot
• Flow
• Proportional Symbol, etc.

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Categories or Types of Thematic Maps

Examples from Hugh Howard, American River College, Cartography Course

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2D: Thematic Maps

• The family of maps that are about a particular topic or theme
• They are more concerned with how things are distributed across space
• Strength - It can make such abstract and invisible concepts visible and comparable on a map
• Reference and thematic maps are not mutually exclusive
• When used in conjunction, thematic and reference maps often complement each other

• Knowledge Level of Audience?

https://www.ers.usda.gov/data-products/farm-income-and-wealth-statistics/charts-and-maps-of-us-farm-income-statement-data/

Modern Mapping Technology - 3D and 4D Visualization

Today, most mapping is done via computers. In a 3D map, any point on the surface is specified by X, Y, and Z. Time and change over time can be the 4^th D

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http://www.esrl.noaa.gov/psd/map/clim/sst.anim.week.html

�Modifiable Areal Unit Problem (MAUP) �Aggregation of data into different areal boundaries�

https://www.wunderground.com/wundermap?covid=1&lat=38.83&lon=-104.83&cm_ven=covid-map downloaded 3-29-2020

MAUP – Different aggregation schemes for the same data. By County on the left and State on the right. The aggregation boundary can influence the interpretation of the same data.

County

State

Modifiable Aerial Unit Problem (MAUP)

• Same Data
• Different Aerial Extent
• Boundaries
• State, County, Zip codes
• What does each communicate?

Colors, Symbology and Projection

Good use of colors and projection, but where is the map legend?

Generally, legends are needed to help viewer understand what the map communicates

Model 4.2 will investigate the use of color, symbology and fonts

https://www.npr.org/sections/goatsandsoda/2020/03/30/822491838/coronavirus-world-map-tracking-the-spread-of-the-outbreak?utm_source=npr_newsletter&utm_medium=email&utm_content=20200402&utm_term=4497755&utm_campaign=goats-and-soda&utm_id=27967792&orgid=141

Summary

• Cartography is both an art and a science
• Maps are fundamental to visualizing geospatial technology projects
• Modern advances technology to produce cartographic visualization make it easy to produce good and bad maps
• The Internet has changed the way that maps can be displayed including the ability to make them interactive
• A full course in Cartography and Visualization can help you create more effective maps! Look at the texts linked to the graphics in this module for good resources and look at the Model Course on Cartography and Visualization. Also see the Concept Modules on Color, Scale and other topics from the GeoTech Center for a review these concepts

See GeoTech Center website (https://geotechcenter.org) �for additional Model Courses and other curriculum resources. ���������Note: some content is a derivative of other authors���

Ann Johnson

Associate Director

ann@baremt.com

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2-15-2021 V8