INTERFACE USABILITY OF A VISUAL QUERY LANGUAGE

FOR MOBILE GIS

Haifa Elsidani Elariss and Souheil Khaddaj

Faculty of Computing, Information Systems and Mathematics, Kingston University London, Kingston upon Thames, U.K.

Keywords: International Visual User Interface, Spatio-temporal Databases and Mobile Phone Applications.

Abstract: In recent years, many non-expert mobile applications have been deployed to query Geographic Information

Systems (GIS) in particular Proximity Analysis that are concerned with the user who asks questions related

to his current position by using a mobile phone. Thus, the new Iconic Visual Query Language (IVQL) has

been developed and evaluated using a tourist application based on the map of Paris. The evaluation has been

carried out to test the various usability aspects such as the expressive power of the language, the query

formulation, and the user interface (GUI). The evaluation of the user interface that is hereby presented has

been implemented through the user satisfaction of two subject groups, programmers and non-programmers.

The results show that subjects found that the IVQL GUI has an excellent software, a good organization if

icons, and is satisfying, with no significant difference between the two groups. The subjects also reported

that they found the learning to operate the system easy, exploring new features easy, remembering the use of

the icons easy, and performing tasks straightforward.

1 INTRODUCTION

Geographic Information Systems (GIS) are

computer-based tools used to handle the geo-

features. In Field Worker Services, they are used by

fire fighters, emergency workers, inspectors, and

utility crews (Fidel, 2007). In road networks, they

provide the ability to organize public transportation

(Repenning, 2006), and query moving objects

(Guting, 2006). Mobile GIS are typically used in

tourist and navigation systems for Proximity

Analysis which includes querying the k Nearest

Neighbour (kNN) and finding the facilities that are

located within a buffer area. The existing Mobile

GIS applications have textual or menu-driven input

but do not provide a user friendly environment and

are aimed at expert users only. Thus, with the urgent

need to develop a visual query language that

provides the mobile user with the facility to

formulate a visual query using expressive icons, an

Iconic Visual Query Language (IVQL) has been

developed using a tourist GIS system. The

evaluation implementation, results, and conclusions

are hereby presented.

2 RELATED WORK

In this section we briefly describe some of the state

of the art visual query languages showing some of

their advantages as well as limitations.

LVIS (Bonhomme, 1999) is a visual query

language for spatio-temporal databases. Metaphors

are used for Querying Visually Spatio-Temporal

Databases (Bonhomme, 2000). The user builds a

visual query by selecting a combination of the icons

(Bonhomme, 2002). Psycho-cognitive tests have

been developed to measure the comprehension of the

metaphors. Two subject groups were chosen:

persons working with GIS and persons who are non-

experts. The results of the experimentation have

shown that the recognition of metaphors is effective

to users without prior experience with GIS. The

results showed that the subjects were able to

recognize the relationship between spatial objects

easily and that the metaphors are well accepted by

both populations.

The Filter-flow (Morris, 2004) and (Morris,

2002) is a visual query language and interface for

large spatial databases. The results of the evaluation

showed that the Filter-flow simplified the learning

process and made the query expression easier.

339

Elsidani Elariss H. and Khaddaj S. (2010).

INTERFACE USABILITY OF A VISUAL QUERY LANGUAGE FOR MOBILE GIS.

In Proceedings of the 12th International Conference on Enterprise Information Systems - Databases and Information Systems Integration, pages

339-342

DOI: 10.5220/0002763903390342

 SciTePress

The above visual query languages have

demonstrated a considerable improvement in the

field. However, none of the above is able to provide

the user with the ability to formulate dynamic

complex queries and none takes into account mobile

users. Hence, the evaluation of IVQL has taken into

consideration the various aspects of usability and has

applied both the user testing as well as the user

satisfaction in order to test them. One of the aspects

that have been evaluated in the work is the user

interface (GUI). The evaluation has been done using

the user satisfaction. Its evaluation, results, analysis,

and conclusions are hereby presented. The other

aspects that have been evaluated are the expressive

power as described in (Khaddaj, 2010) and the query

formulation as described in (Elsidani Elariss, 2010).

3 DESCRIPTION OF IVQL

3.1 Query Constructs

The constructs of IVQL are an operator, a value, and

an object. IVQL is based on smiley icons that are

used to visualize operators, values, and objects. A

complex query consists of multiple simple queries

separated by the ‘and’ operator. The new visual

query language is described in (Elsidani, 2006a) and

(Elsidani, 2006b). Figures 1 and 2 show the

constructs of a simple query and a complex one.

Figure 1: Simple query constructs.

Figure 2: Complex query constructs.

3.2 IVQL Architecture

The system consists of a number of components to

process the visual queries. The IVQL user interface

forms the front end of the software. It is installed on

the target mobile device where the user can

formulate the visual query that is translated into a

text query called the Pivot Language where each

icon is replaced by its name, sent to the GIS server

and saved in a file for later processing. The query

processor, which is implemented as a middleware

between the text query and the Geodatabase,

processes each visual query separately as described

in (Elsidani, 2009). The software architecture is

shown in Figure 3.

Figure 3: Software architecture.

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3.3 IVQL User Interface

IVQL provides the user with two major toolbars and

a middle area where objects are displayed and a

query formulation area at the bottom of the interface.

The horizontal toolbar contains the smiley icons that

represent operations. The vertical toolbar displays

icons that represent themes. The middle area

displays the objects of the selected theme. The query

formulation is done first by selecting a smiley icon

from the horizontal toolbar. The icon is

automatically moved to the query formulation area

which appears at the bottom of the interface.

Second, the user selects the object needed. The

selected object is then moved to the query

formulation area. Figure 4 shows the user interface

after formulation.

Figure 4: The GUI after query formulation.

4 IVQL EVALUATION

A questionnaire consisting of twenty five 7-point

Likert scale questions is used to measure the level of

difficulty, user interface, expressive power of the

visual query language, and the query building. The

subjects are 56 undergraduate university students

divided into two 28-subject groups classified as

programmers and non-programmers. The

programmers are familiar with computers and the

non-programmers are not. Their age varies between

18 years and 21 years. The testing session was

conducted in a classroom equipped with 30 desktop

computers, a teacher’s desktop, and an LCD

projector. The NetBeans version 5.0 Software was

installed on all computers with the J2ME Mobility

Pack and the Wireless Toolkit. The emulator

DefaultColorPhone was used to emulate the

prototype of the IVQL user interface. Each session

started with a presentation of the user interface then

each subject was provided with the questionnaire.

Each session lasted around 2 hours.

5 RESULTS AND DISCUSSION

The collected data is represented visually using a

graphical chart namely the histogram bar chart. The

histogram in Figure 5 shows for each question the

mean of the answers and its respective value as

converted to a score over 100. The score 7 means

that the subject had the best and highest preference

and satisfaction whereas the score 1 means that the

subject had the worst and lowest preference and

satisfaction. The mean scores of the two subject

group are compared to check if the is a significant

mean difference. Figure 6 shows the mean scores of

each question of the questionnaire for the

programmers sample group in blue and the non-

programmers in red. The results also reported that

the mean of the questions scores for each of the

programmers group, non-programmers group, and

both groups are respectively 90.4, 85.9, and 88.1 out

of 100. Finally, the t-test statistic is used to compare

the mean scores of each question then of all queries.

Mean of Questionnaire

5.2

5.4

5.6

5.8

6.2

6.4

6.6

1 3 5 7 9 1113151719212325

Question Number

Lickert Scale out of 7

Mean of

Questionnaire

Figure 5: The average of questionnaire scores.

1 3 5 7 9 11 13 15 17 19 21 23 25

Question Number

Lickert Scale out of 7

Programmers

Non-Programmers

Figure 6: Averages of each group.

INTERFACE USABILITY OF A VISUAL QUERY LANGUAGE FOR MOBILE GIS

341

The subjects reported that they found the

software 88% excellent, 85% easy, and 89%

satisfying. They found that reading icons on the

screen was 79% easy, that the organization of

information was 85% clear, and that the sequence of

screens was 86% clear. The t-test analysis of each

aspect can report that at the 5% level of significance,

there is no significant difference between the means

of programmers and the non-programmers groups.

Hence, it can be concluded that both groups have the

same level of satisfaction about the user interface.

The subjects reported that they found the selection

of the operators 91% easy, the selection of

categories 93% easy, the selection of objects 89%

easy, building simple queries 93% easy, the queries

90% clear, the queries 89% legible, remembering the

language queries 93% easy, the sequence used to

build the queries 90% easy, and using the ‘and’

operator to formulate complex queries 89% easy.

The t-test analysis of each aspect can report that

there is no significant difference between the means

of programmers and the non-programmers groups.

Hence, it can be concluded that both groups have the

same level of satisfaction about the query building

and formulation. The subjects also reported that they

found the learning to operate the system 93% easy,

exploring new features by trial and error 90% easy,

remembering the names and the use of icons 92%

easy, and performing tasks is 90% straightforward.

The t-test analysis of each aspect can report that

there is no significant difference between the means

of programmers and the non-programmers groups.

Hence, it can be concluded that both groups have the

same level of satisfaction about the expressive

power of the IVQL language.

6 CONCLUSIONS

In this paper the graphical user interface (GUI) of an

Iconic Visual Query Language (IVQL) has been

evaluated. Its constructs, architecture, and user

interface have been illustrated using a tourist

example. An experimental evaluation has been

carried out on two subjects groups to test their user

satisfaction with the various aspects of the GUI. The

results showed that the subjects reported a very good

overall reaction with the system and an excellent

user satisfaction with IVQL’s GUI clarity,

consistency, ease-of-use, and query formulation

process. Finally, the analysis reported that subjects

with different background had the same level of

satisfaction with the user interface, the query

formulation, and the expressive power of IVQL.

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