130514| grs60312 ron van lammeren · usability usability making products and systems easier to use,...
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Communication and Visualisation | DIMS
- Usability engineering -
130514| GRS60312
Ron van Lammeren
Maps for Monitoring
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Maps for monitoring
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Geo-Visualisation
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Bertin
Tufte
Ware
Blok
Topics
Usability
Usability engineering
User centered design
Usability evaluation
Trends
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Usability Usability
engineering
CREATE
VALIDATE
http://www.eururalis.eu/eururalis2.htm
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5. Geo-visualization - summary
Actor involvement
Procedural items
Participation level
Communication protocol
Technical issues
Practical requirements
geo-referenced research messages
(un) expected responses
interface
geo-visualisation
Medium is the message
7/49 http://bit.ly/cSNvc1 / Rogers et al, 2011 (p 482 -487)
Usability
Usability Making products and systems easier to use,
and
matching them more closely to user needs and requirements
International standard, ISO 9241-11:
The extent to which a product can be used by specified users
to achieve specified goals with effectiveness, efficiency and
satisfaction in a specified context of use.
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www.usabilitynet.org
http://icaci.org/research-agenda/usability-of-maps-and-gi/
Interactive visualisations
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Usability goals
Effectiveness
● can users do what they want to do?
Efficiency
● how much effort do users require to do this?
Satisfaction
● what do users think about the products ease of use?
The users - who is using the product:
highly trained and experienced users, or novices?
Their goals - what are the users trying to do with the product:
does it support what they want to do with it?
The usage situation (or 'context of use'):
where and how is the product being used?
10/49 Rogers, Sharp, Preece 2011
PLEESE UM
Focus on performance-based facts
Pleasure to use (satisfaction)
Learn easy (learnability)
Effective to use (effectiveness)
Efficient to use (efficiency)
Safe to use (safety)
Error tolerant
Have good Utility (in line with required tasks)
Easy to reMeMber how to use (memorability)
Rogers et al, Interaction Design, 2011
Usability engineering
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Applying a user-centered approach to interactive visualisation design,
Wassink et al 2008
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Engineering stages
1. Early envisioning phase
Analysis of current situation (users, environments, tasks)
- profiles and requirements
2. Global specification phase
Proposal of solutions, present to users and other stakeholders
3. Detailed specification phase
Proposal of solutions, present to users and other stakeholders
Activities:
1. Analysis
2. Design – prototypes (demonstrators, mock ups, etc)
3. Evaluation of prototypes; visual representation and interaction styles
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So....Usability Engineering
Methods and techniques in design and development that focus on usability of a product.
Usability evaluation in all phases of the development cycle, and iterative.
● conceptual model
● early prototypes of a new system
● later, more complete prototypes.
User centered “ the user never makes an error “
Some of the same techniques are used in design and evaluation differently
Different evaluation approaches and methods are often combined in one study
NB: Constraints in budget and time
15/49 http://www.usabilitynet.org/tools/13407stds.htm
Wassink et al 2008
User profiles
Psychological characteristics:
cognitive style, motivation
Knowledge and experience:
ranking novices to experts?
Physical discomfort:
colour blind, pattern recognition
Task related:
role, frequency of use
http://www.usabilitynet.org/tools/13407stds.htm
Users : Homo Ludens
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1. Analysis requirements
Statement about an intended product that specifies what it should do or how it should perform (Rogers et al, 2011; p 355)
Requirements describe the formal specifications required to implement the system
Goals of requirements analysis:
Understand about users, tasks, context
Produce a stable set of requirements
getting requirements right is crucial
the stage where failure occurs most commonly
!! mistakes in a final product are expensive !!
try to understand underlying needs
do not decide for the user, but check with the users
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Iris, sporter
25 jaar
Docente lichamelijke
opvoeding
beoefent triathlon
is wel vertrouwd met pc’s
en mobiele telefoons,
maar weinig
geïnteresseerd in nieuwe
mogelijkheden
Scenario
Het schema van Iris schrijft
een training van 20 km voor.
Ze zal daarvan ongeveer de
helft in het donker afleggen.
Het is mooi weer, al heeft
het de afgelopen dagen wat
geregend.
Kenmerken
Iris traint vrijwel elke dag en loopt/fietst
daarbij grote afstanden.
Dat doet ze bij voorkeur in gebieden
waar weinig autoverkeer is; niet aleen
is dat gezonder maar ze houdt erg van
bosachtige omgeving.
Ze start vanaf huis, minder dan 5 km
van het natuurgebied. Iris kent de
omgeving van haar woonplaats in grote
lijnen, maar is niet vertrouwd met de
precieze ligging van de (fiets)paden.
Haar trainingsschema schrijft per dag
een aantal kilometers voor, maar ze wil
graag per keer de route kunnen
aanpassen aan de omstandigheden. Bij
mooi weer kiest ze graag de mooie
routes, ook al zijn die niet verhard.
Verder loopt of fietst ze niet graag in
het donker op erg verlaten plekken. Ze
heeft haar mobiel bij het trainen altijd bij
zich.
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USE CASE USER SPECS
USE CONTEXT
Ben,
vogelliefhebber
75 jaar (leesbril)
Is precies, neemt alle tijd
voor waarnemen en
fotograferen.
Fanatiek in het spotten
van bijzondere soorten.
Kan overweg met
mobiele telefoon en
internet-applicaties.
Scenario
Voorafgaand aan zijn bezoek aan dit
gebied heeft Ben op het web de
volgende informatie gezocht:
• Algemene informatie over gebied
• Plattegrond, vanwege
parkeerplaatsen en
observatiepunten.
• Vogelsoorten en waarnemingen.
• Gebieden in nabijheid.
Hij heeft alleen aantekeningen
gemaakt over de parkeerplaats, en
een plattegrondje uitgeprint. De rest
hoopt hij ter plekke te kunnen vinden
op borden, of via zijn mobiele
applicatie.
Het is een middag in de herfst, en
Ben heeft zijn auto geparkeerd bij
het informatiebord. Het is droog,
maar in de verte zijn donkere wolken
in aantocht.
Kenmerken
Ben gaat minstens een maal per
week een dagdeel naar een
natuurgebied om vogels te kijken,
soms met kennissen.
Vaak is dat na een melding van
een waarneming, of op bepaalde
momenten (vogeltrek enz.)
Bij erg slecht weer blijft hij liever
thuis.
Hij rijdt auto en wil maximaal 50
km rijden, tenzij er een zeer
zeldzame vogel te zien is.
Hij is erg begaan met
natuurbehoud en wil de
beheerder kunnen waarschuwen
bij misstanden
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USE CASE
USE CONTEXT
USER SPECS
Data gathering techniques
Questionnaires (many users| difficult to design)
Interviews (exploring| time consuming)
Existing documentation (trustworthy?)
Observation (creates understanding| time consuming)
Participation (procedure)
Focus groups (hard to select)
Use different methods, involve all stakeholder groups
Use template for requirement description (e.g. Volere template)
http://www.volere.co.uk/articles.htm 21/49
2./3. Hierarchical Task Analysis
Involves breaking a task down into subtasks, then sub-sub-tasks and so on. These are grouped as plans which specify how the tasks might be performed in practice
HTA focuses on physical and observable actions, and includes looking at actions not related to software or an interaction device
Start with a user goal which is examined and identify the main tasks for achieving them
Task analysis techniques such as HTA help to investigate existing systems and practices
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HTA example
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Verweij et al, 2010 24/49
Usability evaluation
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Usability evaluation
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Example screenshot study for GIS
Goals:
How do GIS users organise and customise the interface?
study common users in daily usage
Users were asked to send a screenshot of their entire screen when working on routine tasks
Questionnaire to provide additional information
Sent to GIS mailing lists
Analysis:
proportion of interface assigned to map-other parts of interface (e.g. toolbars)
User experience
Screen resolution
Results: simple technique to understand how GIS is used in situ
Haklay & Zafiri 2008
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Usability (evaluation)
?
?
Just bought a dog
A big one ?
No, not so big ...
Long hair?
No, short hair !
What colour?
White black spotted...
What a nice dog !
Isn’t it ?
Usability evaluation – how?
Approaches
Usability testing
Field studies
Analytical evaluation
Methods and techniques
Quantitative or qualitative
Formative or summative
Users or experts
http://www.useit.com/jakob/
Evaluation approaches
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Usability
testing
Field studies Analytical
Users do task natural not involved
Location controlled natural anywhere
When prototype early prototype
Data quantitative qualitative problems
Feed back measures &
errors
descriptions problems
Type applied naturalistic expert
Evaluation methods
Method Usability
testing
Field studies Analytical
Observing x x
Asking users x x
Asking experts x x
Testing x
Modeling x
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Generalization, precision, realism
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Usability evaluation
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Usually lab experiments
Performance metrics
Issues based metrics
Self-report measures
Behavioural and physiological metrics
Tullis, Albert 2008
Performance metrics
Best way to evaluate effectiveness and efficiency
Calculated based on specific user behaviours, using scenarios or tasks
Task success (can user complete task, binary or levels)
Time-on-task (how quickly can user perform task)
Errors (number of mistakes made during task)
Efficiency (amount of effort, cognitive/physical, to complete task/number of
steps required to complete a task/combination task success and time)
Learnability (change of efficiency metric over time)
Senaratne et al, 2012
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Issues based metrics
Anything that
● prevents task completion
● creates confusion
● produces an error
● performing the wrong action, missing information, misinterpreting
information, not understanding navigation, etc etc.
Real issues?
How severe?
How frequent?
User groups perform tasks in lab
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Self-report measures
Ask users about their perception of the application and
their interaction with it
Semantic differential scales
Beautiful o o o o o o o Ugly
Likert scales
“The information was easy to find”
strong disagree / disagree / neither agree nor disagree / agree / strong agree
Open-ended questions
(Which 5 elements did you like the least/most? Reasons for assessments)
Standard questionnaires: SUS (System usability scale),
QUIS (user interface satisfaction),
USE (Usefulness, Satisfaction and ease of Use)
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Behavioural and
physiological metrics
Observation of (non)verbal behaviour
Facial expressions (video, electromyogram sensors)
Eye-tracking (analysis of fixations to create a heat map)
Skin conductance, heart rate (arousal)
Pressure on mouse, on seat
http://www.scribemedia.org/2011/07/21/exploring-pros-and-cons-of-behavioral-metrics/
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Eye tracking
http://www.youtube.com/watch?v=WqD2pXqT0Z0
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Other inspection methods
Cognitive walkthrough, stepping through a pre-planned scenario noting potential problems.
Guided by 3 questions:
● Will the correct action be sufficiently evident to the user?
● Will the user notice that the correct action is available?
● Will the user associate and interpret the response from the action correctly?
Valster 2008, MGI thesis GRS-2008-02
Trends
40/49 http://www.objectvision.nl/kml/geso.htm
3D visualisations
Increasing demand for 3D, “realistic” visualizations, with high level of detail and animation
familiarity with new technology (games)
3D, realistic visualizations are aesthetically pleasing
expected benefits of realism
● general expectations that realistic depictions minimize interpretive effort
● real world feels complete, accurate, easy (available instantly and constantly)
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3D better than 2D?
2D and 3D displays support different classes of spatial tasks
2D:
tasks requiring precise relative position, such as metric judgements of distances, sizes, and angles
poor for shape-understanding tasks
3D:
tasks requiring shape understanding, such as line-of-sight judgements, gross scene layout, and object identification,
poor for relative-position tasks.
For many tasks (visual search, memorization etc) 2D icons seems better than 3D-icons
“Display should highlight task-relevant information, and this process of highlighting inevitably entails paring down reality.”
42/49 Hegarty et al 2011, Lammeren et al 2010
Preference for realism
• extraneous realism slowed response time and lead to more eye fixations on both task-relevant and task-irrelevant regions of the displays • some participants persisted in favoring these realistic displays over non-realistic maps.
Hegarty et al, 2011
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Preference for 3D visualizations:
Naïve Realism and Naïve Cartography
Users prefer realistic, complex and high-fidelity displays, even when their performance is lower (extra information is not task relevant, and distracting)
Users have more confidence in data presented in realistic displays
Appreciation of the 3D visualization may transfer to the content of the data
User preferences, even those of domain experts, are not a good indication of display effectiveness; testing required.
Smallman, St John 2005 44/49
3D visualizations
If the data themselves are 3D, the third dimension communicates important information
3D useful for:
visualizing volumes, and sightlines (instead of making mental model combining 2D visualizations)
communication
navigating through areas
Realistic texturing, illumination:
may facilitate feeling of ‘presence’ in a location
may allow affective appraisal of an area
http://assassinscreed.ubi.com/revelations/en-GB/home/ 45/49
Attractive things work better
when we feel good, we overlook design faults
Donald Norman (2002)
“.. any pleasure, derivable from the appearance or functioning of the tool increases positive affect, broadening the creativity and increasing the tolerance for minor difficulties and blockages.
The changes in processing style released by positive affect aid in creative problem solving that is apt to overcome both difficulties encountered in the activity and those created by the interface design.
“Tools that are meant to support serious, concentrated effort (…), are best served by designs that emphasize function and minimize irrelevancies. “
Here the normal tensions of the situation are beneficial. The design should not get in the way; it must be carefully tailored for the task.
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Aesthetics and
perceived usability
Experiments to assess relation between perception of aesthetical value and usability of an application
Pre-experimental measures indicate strong correlations between system's perceived aesthetics and perceived usability.
The degree of system's aesthetics affected the post-use perceptions of both aesthetics and usability.
The degree of actual usability had no such effect.
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Tractinsky et al 2000 ; Lee et al 2010
Some conclusions
Develop with users
(User centered design)
Let users participate
(but test their performance)
Evaluate by usability evaluations
Perform field studies with real users:
context and domain knowledge are relevant
Affect can be an important side effect(check)
(in relation to 2D/3D | abstract /realistic)
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References Rogers, Sharp & Preece 2011 Interaction design Wiley
Wassink et al 2008 Applying a user-centered approach to interactive visualisation design in Trends in Interactive Visualization Advanced Information and
Knowledge Processing, 2009, 3, 175-199
Verweij et al 2010 An IT perspective on integrated environmental modelling: The SIAT case ; Ecological modeling 221: 2167-2176
Haklay, Zafiri 2008 Usability Engineering for GIS: Learning from a Screenshot; The Cartographic Journal Vol. 45 No. 2 pp. 87–97
Tullis, Albert 2008 Measuring the User Experience: Collecting, Analyzing, and Presenting Usability Metrics. Burlington, MA: Morgan Kaufmann.
Senaratne et al 2012 Usability of Spatio-Temporal Uncertainty Visualisation Methods in Gensel et al. (eds.), Bridging the Geographic
Information Sciences, Lecture Notes in Geoinformation and Cartography
Hegarty et al 2012 Choosing and Using Geospatial Displays: Effects of Design on Performance and Metacognition; Journal of Experimental Psychology:
Applied vol 18, 1: 1-17
Lammeren et al 2010 Affective appraisal of 3D land use visualization; Computers, Environment and Urban Systems 34 (2010) 465–475
Smallman, St. John 2005 Naive Realism: Misplaced Faith in Realistic Displays; Ergonomics in Design: The Quarterly of Human Factors Applications 2005
13: 6
Norman, 2002. The Design of Everyday Things. Basic Books, New York, NY.
Tractinsky et al 2000 What is beautiful is usable; Interacting with Computers 13 (2000) 127-145
Lee, Koubekl 2010 Understanding user preferences based on usability and aesthetics before and after actual use Interacting with Computers 22
(2010) 530–543
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130514| rvl | www.geo-informatie.nl
Based and inspired by Rogers et al, Joske Houtkamp, Peter Verweij; MGI/GIMA thesis studies (2000 – 2012) of Bos, Hoogerwerf,
Ottens, Davelaar, de Roo, Momot, Velema, Witte, Gaertner, Zhou, Luisman, Milosz, Getachew, Valster, van Rooij, Gold, Link,
Petrenko, van der Mijden, Smit, Raaphorst.
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Text and pictures from Eururalis, DiWi, Foulkes, GESO, PSPE, QUICKS, VOLANTE projects
Communication
and
Visualisation
Usability engineering
Full screen image with title