the portrayal capability in the geospatial in- formation...

The Portrayal Capability in the Geospatial In-formation Technology Tool Kit (gittok)

Morishige Ota

Kokusai Kogyo Co., Ltd.

Abstract. This paper aims to discuss the portrayal capability included in all-in-one education assistance tool ‘gittok’ developed for the study on Geo-spatial Information Technology (GIT). Gittok is designed based on the geo-spatial information standards to ensure the consistency between relating software modules. Gittok equips the portrayal capability enabled by por-trayal schema, symbol/label style dictionary, gazetteer and Map editor. Por-trayal schema works as a filter to transform spatial data into map data. Gazetteer in gittok is a geospatial index to find the feature. Map editor is a software module for the interactive map design, the feature attribute repre-sentation, and map data exchange. The students can study an overview of GIT and how to produce interactive maps. Today there are very few special-ized software tools to learn GIT based on geospatial information standards. Gittok is useful not only for the university students but also for the engi-neers who wish to study underlying knowledge behind a Spatial Data Infra-structure (SDI) and a geospatial application.

Keywords. Education assistance tool, Geospatial Information Technology, Geospatial information standards

1. Introduction This paper focuses the discussion on the portrayal capability in the educa-tion assistance software tool kit ‘gittok’ [pronounced: jee-tock, ʤiːtɒk]. Gittok was developed as the introduction to Geospatial Information Tech-nology (GIT) for students in the higher education and engineers who wish to study the underlying technology behind SDIs. GIT comprises a collection of knowledge areas; they are modeling, acquisition, management, analysis, exchange and representation (Ota, 2012). Today, very few software tools are specialized for the education to teach what is GIT based on geospatial in-

The International Symposium on Cartography in Internet and Ubiquitous Environments 2015 17th - 19th March, Tokyo

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formation standards. However, Robinson, et al. (1995) emphasized the im-portance of standards as fallows. ‘One of the most important concerns for future cartographers will be stand-ards. Increasingly, local units will feed data up to central (state, national, global) coordinating organizations. These organizations will be responsible for setting standards and facilitating data distribution. Standards are need-ed for data quality, data exchange, hardware and software interoperability, and data collection procedures. Knowledge of data models, features, attrib-utes, and data set linage are examples of concepts that cartographers must now learn.’ Gittok allows the students to acquire, manage, analyze, exchange, and por-tray geospatial data in compliance with conceptual schemata. These sche-mata were designed by referring to the geospatial information standards. The students can gain an overview of GIT, through ‘hands-on’ operation, spatial analysis, data exchange, geo-library management, and map design-ing. As knowledge area ‘representation’ includes knowledge units (sub-areas) such as graphic design, semiology, projection, symbolization, typography and color theory. Today, we can find enormous study results provided from these scientific research fields (Bertin, 1967), (Robinson, et.al. 1995), (MacEachren, 1995), (DiBiase, 2006), etc. Moreover, researches on digital cartography such as analytical cartography (Moellering, 2000), multimedia cartography (Cartwright, et.al. 2007), cy-bercartography (Taylor & Lauriault (Eds.), 2014) and Web cartography (Muehlenhaus, 2013) are progressing rapidly. Today’s mapmaking can be understood as the transformation from geospatial data into not only inter-active maps but also virtual and augmented realities. It seems that car-tographic methodologies will be melt into the ocean of ICT. However, we still have issues to think in the field of cartography. For example, the map of world heritages served by UNESCO enables to see the Home Pages of heritages by clicking the thumbnails displayed on the base map (http://whc.unesco.org/en/statesparties/jp). It has functions to visualize multimedia feature attributes. Interactive map services on the Web such as Google maps and Yahoo maps allow the mash-up of multime-dia information by the users. However thematic attribute data types such as image, video, audio and URL are not defined explicitly in the international geospatial information standards. And it is difficult to find standard rules for the construction of interactive maps. Gittok enables the students to design interactive maps in compliance with a portrayal schema. This paper first introduces gittok, followed by the discus-sion on the cartographic functions, the proposal of the transformation


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mechanism from geospatial data into interactive maps, and the report of the first experimental course held from April to July 2014 at Chuo Universi-ty, Tokyo, Japan. Finally the conclusion and future issues are remarked.

2. GIT Tool Kit (gittok)

2.1. GIT with Modeling The purpose of gittok is that students gain an overview of the whole concept of GIT. GIT is defined as a set of information technologies for modeling, acquisition, management, analysis, exchange and representation of geospa-tial information. Dibiase et al. (2007) defined GIT as the specialized set of information technologies that support data acquisition, data storage and manipulation, data analysis, and visualization of geo-referenced data. How-ever this definition does not actually clarify the conceptual modeling of real world phenomena. Reliable data acquisition and analysis cannot be per-formed without a conceptual model such as an application schema or a data specification. For example, the sequence from reality to geographic data is explained by ISO 19109 ― Rules for application schema (ISO, 2005b). It is that a description of feature types is made at first from the universe of dis-course, followed by the design of an application schema as a formalized model, finally the geographic data is acquired in compliance with the appli-cation schema. Transformations from geospatial data to a rendered map are impossible without an application schema describing definitions of feature types as an abstraction of real world phenomena. Therefore, ‘modeling’ should be added as a knowledge area of GIT. Technology schematizes scientific knowledge for practical purposes. The schemata in gittok were designed for the education based on the geospatial information standards to ensure the consistency and practicality of scien-tific knowledge areas.

2.2. Overview of the GIT Education with gittok Many teaching tools have been developed in the world. For example, in 1990s, there was excellent software called GISTutor for the education to study what is GIS (Raper and Green, 1992). However very few software tools are specialized for the education to teach what is GIT based on geo-spatial information standards. Educations and trainings using existing packages are good for learning how to use the software. However to under-stand the underlying knowledge of GIT, all-in-one software tool specialized for the education should be prepared. In Gittok, a geospatial data is a self-descriptive dataset called a ‘Kit.’ It con-sists of an application schema, a base map for digitizing geometric attrib-


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utes, a declaration of a coordinate reference system, parameters of coordi-nate conversion, in addition, pointers to multimedia attributes such as im-ages, videos, and sounds. The same Kit is carried between different software modules without translations. It cannot be possible without consistency between different modules. Students can study that application schemata are modeled not only for the specification of data acquisition but also for analysis and representation at first, metadata is useful for retrieving spatial data managed in the geo-library at second, a Kit can be encoded in XML document and it can be ex-changed between other GISs at third, and finally a different portrayal sche-ma provides a different map from the same Kit. Knowledge areas and the relevant software modules containing in gittok is shown on the title page (window) of gittok (Figure 1). The students can open each module and can study each knowledge area by clicking the pictogram. They are discussed in the next chapter.

Figure 1. The title page of gittok.


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3. Knowledge Areas and Software Modules

3.1. Modeling Model is defined as ‘abstraction of some aspects of reality’ (ISO, 2005b). ‘Some aspects of reality’ refers to phenomena in the universe of discourse. A conceptual schema called an application schema is a formal description of feature types and their relationships. Thus, modeling is recognized in this paper as a conceptualization from the real world to the application schema that describes the feature types and their relationships. The General Fea-ture Model (GFM) specifies rules (meta-classes) for the description of fea-ture types and their relationships. A feature type has properties such as attributes, operations, associations and inheritances between other feature types. Attributes are classified into spatial (ISO, 2003a), temporal (ISO, 2002), locational (ISO, 2003b), and thematic (ISO, 2005a). The gittok GFM is a simplified but practical version of the ISO GFM. The software module called ‘Modeler’ equips a capability of the application schema modeling. The students can learn how to schematize an application schema in order to encompass the universe of discourse. There are few sim-ilar educational tools in existence today that facilitate a similar learning experience.

3.2. Acquisition Geospatial data acquisition is a transformation from real world phenomena into a geospatial dataset that is comprised of feature instances and associa-tion instances. An application schema restricts types of features and associ-ations, and their attributes. A structure of instances and their relationships follows an instance model. ISO 19118:2011 ― Encoding (ISO, 2011) defines instance model as ‘representation model for storing data according to an application schema.’ Gittok provides the simplified instance model for the education. Gittok is not a general purpose GIS, and therefore impossible to try various data acquisition methods. However students can practice map digitizing to capture geometric attributes with topology and can embed images, movies, audio files, URLs and other thematic data into feature instances through the software module called ‘Editor’ (Figure 2).

3.3. Management Data management is a process of dealing with or controlling geospatial data. Gittok manages geospatial data through ‘Manager’ where the students can store and query the Kit files. Additional procedures such as updating, analysis, exchange and representation can be practiced through ‘Manager’.


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Figure 2. ‘Editor’ with pages for acquisition of geometries, photos, web sites, memos, and addresses as attributes of a feature.

Geospatial data is managed by a geo-library, that is defined as a digital li-brary filled with geoinformation - information associated with a distinct area or footprint on the Earth’s surface - and for which the primary search mechanism is place (National Research Council, 1999). The geo-library in gittok consists of a set of metadata that is defined as ‘information about a resource’ in ISO 19115-1:2014 ― Metadata ― Part 1: Fundamentals (ISO, 2014). The metadata specification defined in gittok is a tiny profile of ISO 19115-1. Its elements are title, URL of the kit, overview, keywords, responsi-ble party, geographic extent, and publication date. The geo-library is not distributed on the Web. However students can learn how to create metadata and how to retrieve a Kit from the personal geo-library.

3.4. Analysis Geo-data analysis is one of the core knowledge areas of GIScience and ana-lytical cartography, and it encompasses a wide variety of operations whose objective is to derive analytical results from geospatial data. In gittok, the aim of ‘Analyst’ together with ‘Modeler’ is provided for students to study an object-oriented approach to deriver information by operations defined in feature and association types. However there are many different schools of thought or approaches (Dibiase et al., 2006). Learning every method in a short time is impossible because of the complexity and enormous variety. Analysis tools executed through ‘Analyst’ are limited to software modules applying basic computational geometry. However, the author recommends that teachers and students add additional analysis tools in gittok, as it is the study along with the purpose of gittok. Methods for building additional


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tools are provided in a set of examples in the original program. Currently there is no capability for image processing, as gittok is not a field-based software package. This is an issue for future development.

3.5. Exchange Gittok has the module called ‘Exchanger’ to encode and decode XML data such as an application schema, a Kit, metadata, a set of parameters of Co-ordinate Reference System, etc. Gittok does not use Geography Markup Language (GML) (ISO, 2007) for transformation at this time, because git-tok uses its own GFM, and because GML is difficult to comprehend for be-ginners in short period of time. However, students will be able to under-stand ISO and OGC standards easier after learning GIT with gittok.

3.6. Representation Representation, in the gittok environment, refers to styling a map dataset by applying a portrayal schema. A portrayal schema is a set of rules specify-ing how to style maps. The portrayal schema is equivalent to symbol refer-ences described in ISO 19117:2012 ― Portrayal (ISO, 2012a). In gittok, the portrayal schema with symbol/label style dictionary is designed in compli-ance with the General Portrayal Model (GPM). This is analogous to that an application schema is designed in compliance with General Feature Model (GFM). A portrayal schema describes the correspondence relationships between attributes and symbols/labels in order that the module ‘Cartogra-pher’ can translate into a map from a Kit. Portrayal capability in gittok is discussed in detail at the next chapter. Interactivity is the degree to which users can manipulate and redefine a map (MacEacheren, 1995). Today, most digital maps on the web are inter-active. ‘Cartographer’ enables the students to design personal interactive maps. This module comprises five sub-modules; Symbol style designer, Label style designer, Portrayal schema designer, Gazetteer designer, and Map editor. These sub-modules are equivalent to knowledge units included in the knowledge area of digital cartography.

4. Cartographer

4.1. Symbol/Label style designer Symbol style designer enables the students to design graphical representa-tion styles of points, lines, and areas in compliance with the symbol style schema. Label style designer enables the students to design labels as repre-sentations of character string attributes in compliance with the label style schema.


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4.2. Portrayal schema designer Portrayal schema designer consists of three parts (Figure 3). The first part enables the students to select the application schema and the symbol/label style dictionary for designing of the portrayal schema, and open/save of the portrayal schema.

Figure 3. Portrayal schema designer

The second part allows the students three actions on the portrayal schema design. First, the students may declare the relationship between feature attribute and its portrayal for the general-purpose mapping. Second, the students may declare the drawing method of the choropleth map. Third, the students may select multimedia feature attributes for their graphic repre-sentations as information pages. The third part consists of a table of symbol styles and a table of label styles. These tables are used to declare the attribute type and its symbol or label for general-purpose maps, and also to declare the color gradients for choro-pleth maps.


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Figure 4. General Portrayal Model (GPM) described in UML

The structure of Portrayal schemata is specified by GPM (Figure 4). Accord-ing to GPM, a portrayal schema (PortrayalSchema) associates with 'fpPairs'. This is a set of data of which type is FeaturePortrayalPair. FeaturePortray-alPair indicates which feature type is portrayed by which modifier. A modi-fier is information how to draw a feature on a map. 'generalModifiers' is used to draw general purpose maps. It indicates a symbol (point, line area) and/or a label to show a feature on a map. Attrib-uteStylePair is a combination of a geometric attribute type and a corre-sponding symbol style. 'thematicModifiers' is prepared to draw choropleth maps. It is required to select a feature type and its polygonal attribute to draw choropleth maps. The students select an attribute type for color gradients. If the attribute type is numeric, colors can be selected to each level from the lowest to the high-est value. If the attribute type is Boolean, two colors can be selected accord-ing to true or false. If the attribute type is Character string, then the corre-spondence table is prepared to show the correspondence between character strings and colors. ThematicCondition stores these parameters. 'infoPages' is used to show information pages, which are windows to show multimedia feature attributes. Gittok prepares six types of information pag-es: address, memo, photograph, video, sound, and Web site. If multimedia feature attributes are chosen on the GUI, a symbol representing the feature becomes ‘informed symbol’. It is a symbol linking to the corresponding fea-ture. AttributeType is a selected multimedia attribute type. The portrayal schema designer enables the students to design portrayal schemata by filtering feature types and their attributes to draw on maps and


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by selecting symbols and labels to represent them on maps. Other types of thematic maps are impossible to draw at this time. It is a future issue.

4.3. Gazetteer Gazetteer is defined as ‘a geographical index or dictionary’ according to the Oxford English Dictionary. It means gazetteer can be viewed from two sides. The role of geographic indexes in atlases is to find a page and a place where the user searches. Most of the map service sites on the web provide the fea-ture finding mechanism. For example, Wikipedia commons provides the Atlas index (http://commons.wikimedia.org/wiki/Atlas_index) to find in-formation about the countries in the world.

Meanwhile, architecture of the geographic name dictionary is discussed in the researches of a SDI (López-Pellicer, et al., 2007), (Martins, B., 2011). Items in the record of gazetteer are named places (and their history), their spatial location (in various representation), their relationships to other places (e.g., part of relations), classification (using a referenced typing scheme), and other metadata properties (e.g., source attribution). There are many countries to establish the national gazetteers, for example, Australia, Canada, United Kingdom, and United States of America.

According to ISO 19112: 2003 ― Spatial referencing by geographic identifi-ers (ISO, 2003), gazetteer is defined as ‘directory of instances of a class or classes of features containing some information regarding position.’ Posi-tional information need not be coordinates, but could be descriptive. Such positional information is called geographic identifier. However today, there are many types of information resources related to geographic features not on the real world but also on the virtual Web-space. ISO 19155:2012― Place identifier Architecture (ISO, 2012b) defines the term ‘place’ as an identifia-ble part of any space. Thus, the term ‘place identifier’ is used in gittok.

A gazetteer designer is a tool to define a gazetteer in compliance with its schema. A record for the gazetteer is a combination of place identifier and its position. The students can see the found feature by the selection of an item on the list of place identifiers. The students can see the corresponding feature shifted automatically to the center of the screen. A gazetteer design-er can create different gazetteers as the students select the different location and position types. ISO (2003b) defines gazetteer as ‘directory’ not ‘diction-ary’. In gittok, a gazetteer is primarily a simple directory, but it is a preface to lead the multimedia feature attributes. Therefore gittok gazetteer can also works as a dictionary, if each feature has a sufficient number of attrib-utes.


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4.4. Map editor Map editor is used for the presentation of multimedia feature attributes. Generally, there are two methods to present feature attributes. One is to put pushpins or markers on maps as POIs. The other is to present graphic fea-tures as informed symbols. The students can obtain attributes through the symbol which links to attribute values. Conventional definition of feature, i.e. ‘location and attributes’ still remains here. The difference between POI and informed symbol is that POI is independent from a relevant feature. However, an informed symbol is a proxy of a feature.

Figure 5. The pictogram box on the informed area symbol, and an image and a memo appeared by pictgram selections.

Gittok allows the students to use informed symbols, because they do not need to see a pushpin forest. The pictogram box appears when the cursor is moved on the feature (Figure 5). The students can see a multimedia at-tribute by push the appropriate pictogram in the pictogram box. Meanwhile, gittok does not reject POI. It can be defined as a feature type in an applica-tion schema, if it is required. It depends on the universe of discourse. Gittok also allows the students to create choropleth maps (Figure 6). Map editor provides three functions for map making: 1) zooming and panning, 2) location of a title, a subtitle, a north arrow, a scale-bar, and a legend, and 3) relocation of labels to the place where they can be viewed easier.


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Figure 5. The choropleth map and the pages used for the map making.

A map is one of the final products provided by gittok. Conventionally a map has been a static image printed on a paper. However today, dynamic inter-active maps are commonly used. So, the exchange of maps is an exchange of map data comprising symbols, labels, marginal information, the pointer to the Kit, and the portrayal schema.

5. Experimental Course The author has carried out a semester-long course from April to July 2014 for ten forth-year undergraduate students at the Department of Informa-tion and Systems Engineering at Chuo University in Tokyo, Japan. Accord-ing to the answers of a questionnaire given after the last class, the nine stu-dents who responded answered they were using web-map services often on smart-phones and PCs during their daily life. However most of them did not know the term ‘Geographic Information System’ and none of them had heard the term ‘Geospatial Information Standards’ before taking the course. However, all students could finish the course. After the end of the course, the author gave the final exercise to the students instead of the final examination. It was to create a multimedia interactive map to show landmarks, roads and others existing in the area assigned to each student. They modeled application schemata by themselves at first. Then they went to the assigned area to get information of features. They digitized and edited geographic features with multimedia attributes such as


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photos and texts. They made the metadata. They designed symbol styles, label styles and the portrayal schema for the mapping. And finally they submitted the interactive map with related information such as the applica-tion schema, the metadata, the symbol/label style dictionary and the por-trayal schema. All students could submit the products. From the results of the survey and the final exercise, it was confirmed that to teach the concepts of GIT based on geospatial standards to new students is possible.

6. Conclusion and Future Issues This paper first introduced the GIT education assistance tool ‘gittok’, fol-lowed by the discussion of the cartographic functions, the proposal of methods of the transformation from geospatial data into interactive maps, and the brief report of the first experimental course. The architecture of gittok is designed based on the geospatial information standards to ensure the consistency between software modules. Gittok enables the students to design the portrayal schema in compliance with GPM. A portrayal schema works as the restriction to transform from the geospatial data into map data. Map editor enables the students to edit interactive maps, to present multi-media attributes on the map, and to exchange map data. The students can retrieve multimedia attributes of each feature from the informed symbol drawn on the screen. Today very few software tools are specialized for the education to learn what is GIT based on geospatial information standards. Gittok will be useful software for the GIT educations and capacity buildings. However, gittok is still under development. Dynamic map display by apply-ing temporal attributes should be developed. In addition, gittok has no ca-pability of the field based image processing, which is another area for de-velopment. Knowledge on standard cartography, such as color theory, ty-pography, visual variables, and symbol design, etc. could not teach in the course, because the basic purpose of this course is to learn technologies enabling Geospatial Information Services. Fortunately, a semester course for undergraduate students will continue. The amount of information that can be conveyed in the half year will be possible to consider through future teaching experiences. Gittok is open source free software. It can be downloaded from the Web site http://stinfodesign.net/gittok/. The author will improve this software and attached tutorials and slides to answer the comments from users. The au-thor hope that the people of the geospatial community will benefit from their use, and will actively participates in improving this software.


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Acknowledgements The development of gittok was supported by Grant-in-Aid for Scientific Research (A), Ministry of Education, Culture, Sports, Science and Technol-ogy (Project number: 21240075. Project leader: Yasushi Asami, The Univer-sity of Tokyo). I am grateful to the members of the GIT group established under the project (Leader: Koichi Kubota, Chuo University) and other members of this grant project for their valuable comments and suggestions. I am also grateful to the Geospatial Information Authority of Japan and many people for their kind advice and feedback.

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