GIS Customization for Diachronic Spatial Data ...

GIS Customization for Integrated Management of Spatially Related Diachronic Data

between geographic features and their representation, DB management tools for the archiving and data retrieval and multimedia tools for playback. The combination is obtained using the appropriate COM tools (Fig. 2) using the programming language Microsoft Visual Basic.

K. D. Papadimitriou, T. Roustanis Dep. of Rural and Surveying Engineering Polytechnic School Aristotle University of Thessaloniki 54622, Thessaloniki, GREECE

Abstract-This study presents the development of an interface for the management of diachronic spatial data that describe the evolution of an area. Subsequent data that represent specific spatial characteristics for various time periods are organized and processed in a customized GIS environment. Vector and raster data (old scanned maps, air photos and satellite imagery) are related based on their spatial and temporal properties and they are archived adequately. Part of the data set contains digital documentation in form of digital photos, audio and video files, thus the customization includes multimedia playback for selected geographic features that are described by these means. As a case study is used an extended area in Northern Greece that includes various archaeological sites along Egnatia road (nearby ancient Via Egnatia).

The majority of GIS applications in the field of archaeology are dedicated to prediction models for site locations [7] rather than an interface for digital documentation [8], [9]. The aim of this interface is to facilitate GIS users from various disciplines, who cope with diachronic spatial data and the relative digital documentation, and who require special functions (apart from GIS functionality) that are not offered from official software distributions. II. MATERIALS As a case study is used the surrounding area of Egnatia road at the prefecture of Seres in Northern Greece (Fig. 1). Contemporary Egnatia road is a major motorway that follows the ancient Via Egnatia, build by Romans, that links several archaeological sites from early Hellenistic through late Byzantine years. As a consequence it has a special historic and archaeological interest.

I. INTRODUCTION The majority of scientific researches that imply field work (such as ecology, archaeology and geology) involve large amount of heterogeneous data sets from multiple sources that may contain both spatial information (raster, vector, tabular data and meta data) as well as non-spatial [1] such are digital documentation (reports, photos, sound recordings and video) for subsequent time periods. Specialist 's needs for appropriate management and representation of both geographic data and multimedia files within the same interface imposes the combination of different components in customized software environments [2], [3], [4]. This paper demonstrates the capabilities of a customized GIS environment that is used for the management of geographic and multimedia data that describe an area of interest through time. The customization is based on eight developed forms which provide geographic data archiving and representation based on the spatial and temporal properties of features [5] as well as multimedia playback for spatially referenced documentation data [6]. The development was performed with the combination of GIS and COM tools, taking advantage of GeoMedia Professional and Microsoft Visual Basic. The result of this collaboration offers an integrated interface for: a) the massive import of imagery, b) the linking of selected geographic features to multimedia files, c) the automated attribution of metadata to raster files, d) the discrimination among vector data which represents features that "are" and "are not" recognizable over selected imagery, e) the automatic display of geographic data at any selected area, f) the selective display of available data over the working view, g) the selective display of spatially related vector data over selected raster data and h) the automated playback of linked multimedia in GIS environment. The developed functions are presented using a data set that describes the archaeological sites along Egnatia road (ancient Via Egnatia) at the prefecture of Seres at Northern Greece.

Fig. 1. Map overview showing the study area.

A. Data The historical documentation of the study area consists an heterogeneous data-set that contains three major categories of data types: a) Raster Data, including aerial photos, aged from 1945 to 1996, at scales from 1:6000 to 1:42000, satellite images, scanned historical maps, aged from 1901 to 1945, at scales 1:20000 to 1:200000, scanned topographic maps (scale 1:50000), scanned topographic diagrams, aged from 1925 to 1987 (scale 1:5000) and scanned geological maps. b) Vector Data describing administrative boundaries, the coast line, urban limits, buildings (structures), soil data, coverage data and archaeological traces. c) Multimedia documentation from field work (findings, excavation details, oral reports etc) containing digital photos, audio and video files [10]. B. Software Component Objects The interface combines GIS tools for the analysis of the spatial relations

Fig. 2. Architecture of customization and schema of collaborating components.

The graphic environment that is used to host the developed interface is GeoMedia Professional and all the geographic operations are executed using its component objects [11]. The management of data is carried out using the SQL Server which can cope with large amount of data, while MS Media Player is controlled for multimedia playback in GeoMedia 's environment. The following component objects were used from Geomedia Professional: a) GMMapview object (Fig. 3.a) which is used for Map View display and provides the methods and properties to control the display, retrieve information as well as extend automation functions for a Map View display. It defines the cartographic environment (interface) of the application. b) LegendEntries object (Fig. 3.b) is a collection of legend entry objects that comprise a legend (features that are displayed on the Map View). It is used to define the overlay sequence of cartographic layers and the way of representation. c) EventServer object (Fig. 3.c) which listens to a single or multiple Map Views for window, keyboard, and mouse events occurring in the active Map View. It recognizes events occurring in a Map View and processes them according to an EventControl object. It serves the interaction between the user and the application. d) EventControl object (Fig. 3.d) associates and disassociates an EventServer object (as described) with one or more GMMapView objects. The EventControl object also provides exposed automation for responding to events occurring in an associated Map View. The EventControl object handles the actual communication between a Map View and the occurring events. e) SmartLocateService object (Fig. 3.e) which contains methods and properties for locating objects within specified geometric regions. These regions can be within or intersecting a closed geometric object (such as a rectangle). They can also be within or intersecting a circle with a radius that is a specified number of pixels from a locate point. This service defines the spatial criteria for the location – selection of displayed geographic features. f) LocatedObjectsCollection object (Fig. 3.f) contains all objects found by a locate method for the SmartLocateService object. This collection can contain geometry objects (objects having a located geometric element) or raster objects. The collection of located (selected) objects is the subset of displayed features that will be used later for geoprocessing. g) OriginatingPipe object (Fig. 3.g) defines a database query criterion and produces a recordset according to that criterion and provides is used to specify the database table from which to extract data, an SQL-equivalent WHERE clause to limit the retrieved records, a spatial criteria to set geometric extents and relationships to limit the retrieved records and to generate an output recordset according to the query requirements. This output recordset has been defined spatially by the LocatedObjectsCollection object and extracted through the OriginatingPipe object. h) Geographic Data Objects – GDO (Fig. 3.h) are programmable database objects based on the Microsoft Data Access Object (DAO) model. The

Microsoft Component Object Model (COM) design provides the automation for data access and data update. GeoMedia combines DAO concepts and COM with geographic aspects of geodetic coordinate systems, geometry, and spatial filtering. Additionally, two component objects from Microsoft Visual Basic was used: i) Scripting.FileSystemObject (Fig. 3.i) that allows the creation, delete and gain of information about folders and files and j) Windows Media Player ActiveX control object (Fig. 3.j) which adds Windows Media Player functionality to other programs (it brings multimedia playback capabilities in the environment of GeoMedia). The following schema (Fig. 3) demonstrates the collaboration between the component objects that has been used.

Fig. 3. Schema of the collaboration between the component objects that has been used in the customized environment.

III. RESULTING FUNCTIONS Three main categories of functions (tools) are defined; Input, Storage and Management and Display, which provide the following operations: A. Input This category contains three forms for massive import of imagery (Fig. 4.a), vector digitizing (Fig .4.b) and the linking of selected geographic features to multimedia files (Fig. 4.c).

Fig. 4. The first category of functions is used for data input and contains two GeoMedia commands (a,b) and a form for multimedia documentation associating media files (photos, audio, video) to vector data (c).

Massive input of raster data and vector digitizing are provided from original GeoMedia tools and the link between geographic features and multimedia files is done using a developed form. B. Storage and Management The second category is dedicated to the update of descriptive properties (Fig. 5.a), the discrimination among vector data which represents features that

"are" and "are not" recognizable over selected imagery (Fig. 5.b) and the automated attribution of metadata to raster files. Those forms are used to update the descriptive properties of input data (raster or vector), linking attribute 's values with related table indexes of the data-base while the attribution of raster metadata is done automatically, based on a predefined manner for the file names (raster files without appropriate name require that the user inserts the attribute values manually).

the other hand raster data, through this kind of relationship with vector data, can participate indirectly in both spatial and non-spatial queries.

Fig. 7. The display operations, in the third category of functions, are controlled by a) a selection form, b) a form for displaying desired image based on selected position, c) a form for displaying vector data related to selected image and d) a window for automated multimedia playback.

Fig. 5. The developed forms of the second category of functions are used for the management of descriptive properties (a) and for the definition of optical and spatial relationship between selected vectors and images (b).

File names of raster data to be imported, has to conform with the following format in order to automate the attribution of metadata (Fig. 6):

Fig. 6. File name format for the automated attribution of metadata to raster files (a: Image Type ID, b:Image ID, c: Day, d: Month, e: Year, f: Scale).

Image type ID (Fig. 6. a) describes the type of image (scanned map, airphoto, satellite image), Image ID (Fig. 6. b) is a code number for each image, Day (Fig. 6. c), Month (Fig. 6. d) and Year (Fig. 6. e) describe the date and Scale (Fig. 6. f) refers to the denominator of the scale. C. Display This set of functions is used for displaying data interactively and include forms for the automatic display of geographic data in any selected area (Fig. 7.a), the selective display of available data over the working view (Fig. 7.b), the selective display of spatially related vector data over selected raster data (Fig. 7.c) and the automated playback of linked multimedia files in GeoMedia' s environment (Fig. 7.d). The functions of the above three categories are organized respectively in three new menu items at GeoMedia 's menu bar (Fig. 5,6,7) as well as the according toolbox, from which the described operations can be executed. IV. CONCLUSIONS The majority of raster data is used for representing the differences over subsequent time periods (evolution of the area) In the same time, archaeological traces (vector data) although spatially related with overlapping raster data, they are not visible (or recognizable) on every image (e.g. a new archaeological finding appears on the post- excavation air photos but not on the old historical maps).In such cases the developed interface allows this discrimination and lets the user define relationships that are based on the recognition of geographic features (vector data) on an image (which are already spatially related). Through the above new kind of relationship, geographic features without temporal properties are related to time-stamped imagery. This is a side-way for their attribution with time and could be used as a bridge for spatio-temporal analysis (of data without temporal properties). On

During extended fieldwork (such as archaeology implies), a large amount of digital documentation is produced that in many cases contains much more details than tabular data may describe. In such cases multimedia association and playback provides a more detailed description of examined features. Attributing geographic features with multimedia files (additionally to standard information) facilitates their description and understanding from researchers and inexperienced users (viewers). The developed functions could be useful in various GIS applications that are used for spatio-temporal documentation and data management or diachronic analysis, such as forestry and vegetation monitoring, landscape and urban change detection, where combinations of raster and vector data are taking place. Further development includes automatic feature recognition and extraction (from raster data) as well as customization using open source software. To conclude, the presented customization brings together common operations from different software (GIS, DB management, multimedia) that provide an integrated interface for storage, management, retrieval and representation of geographic and spatially related data from various time periods. ACKNOWLEDGEMENT We appreciate the contribution of D. Kaimaris (Phd Student at the Department of Rural and Surveying Engineering) who gave us part of the data he is using in his thesis study and demonstrated us practical matters on the management of spatial data for archaeological documentation. REFERENCES [1] [2]

[3] [4]

[5]

Y. Zhou, ”Multi-source data management in soil erosion monitoring system at regional scale”, Geoscience and Remote Sensing Symposium, Proceedings, vol. 5, pp. 2875 – 2877, IGARSS 2004. L. Bordoni, A. Colagrossi,” A Multimedia Personalized Fruition of Figurative Artistic Heritage by a GIs-Based Methodology“, Multimedia Computing and Systems, IEEE International Conference, Vol. 2 pp.184 – 188, July 1999 S. Fabrikant, ”Spatialized Browsing in Large Data Archives“, Invited seminar. Queen's Centre for Knowledge-Based Enterprises (KBE), Kingston, Canada, Mar. 26, 2003. B. Ducke, “Open-Source-GIS-Technologie, Stand und Perspektive”, presented in the Berlin Head Office of the German Archaeological Institute (DAI) during the conference “GIS in der Archaologie”, (http://www.arc-team.com/archeos/), 2006. T. Roustanis, “Application Development and Database Model to support Spatiotemporal analysis on Common Utility Network Damages through Data Warehouse technology”, Msc Thesis, Dep. of Rural

and Surveying Engineering, Aristotle University of Thessaloniki, Greece, 2004 [6] K.D. Papadimitriou, “Location Based Information System for Decision Support in Emergencies”, Ph.D. dissertation, Dep. of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Greece, 2004 [7] K.L. Wescott, R.J. Brandon, “Practical Applications of GIS for Archaeologists”, Taylor & Francis, Great Britain, 2000. [8] C. Güney, R.N. Çelik, “Multimedia Supported GIS Application for the Documentation of Historical Structures”, Survey Review, Vol 37, No 287, pp. 66-83, 2003.

[9]

Bakourou, E., Tsioukas, V., Katzougraki, I., Stylianidis, E., Papadimitriou, K., Patias, P., “The promotion of cultural heritage through internet using advanced audio-visual information: The venetian castles of Peloponnisos”, IAPRS&SIS, Vol. XXXIV, Part 5, Com V, Corfu, Greece, pp. 298-301, 2002. [10] D. Kaimaris, “Photogrammetric processing of Digital Images in service of Archaeological research, tracing Via Egnatia from Amfipolis to Philippoi”, Ph.D. dissertation, Dep. of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Greece,2006. [11] Intergraph Corporation, ”Geomedia Professional Object Reference”, 2005.