Updating in Multiple Representation Databases: Model Generalization and Object Matching Stage
ISBN 978-85-88783-11-9
Authors
1çobankaya, O.N.
1GENERAL COMMAND OF MAPPING Email: osmannuri.cobankaya@hgk.msb.gov.tr
Abstract
Although there is only one world, representing of this reality can change according to the purpose and scale. National Mapping Agencies are responsible to produce map series at different scales. This situation reveals an updating problem of the digital map series with a relevant method. Updating the digital map series is a process requiring time and cost because of the volume of data at national level. In order to perform this process more efficiently, dataset with lower resolution can automatically be updated and generalized after the master dataset with high resolution is manually updated. In this study, it is aimed to establish the relationship between spatial objects belonging to the same world reality in a multiple representation database and to apply the revisions in master digital landscape model to the other digital landscape model with low resolution automatically. Data between 1:25K-1:500K scales were used at the application stage of this study. In our country, General Command of Mapping is responsible to produce topographic maps between 1:25K-1:500K scales. Basic topographic map scale is 1:25K. Topographic maps between 1:50K-1:100K scales are produced by using the base scale (1:25K) cartographic vector data and cartographic generalization methods. VMAP1 data are used for the production of 1:250K and 1:500K scale topographic maps, as well. There are various data models with different resolutions and scales in existing data and production structures. Geometric and semantic abstraction levels of the spatial objects change by increasing/decreasing the resolutions. In existing structure, there is no relation (horizontal and vertical) between the data at different resolutions. In this study, it is aimed to create a multiple representation database including the 1:25K-1:500K representation levels by the help of existing conceptual data models, data dictionaries, and production directives by using 1:25K scale of basic digital landscape model. A multiple representation database is created by model generalization approach and object matching techniques. ArcGIS software and the objects of ArcObjects are used. For these purposes, a model generalization and object matching program named ModGen is developed. This program automatically performed creating the multiple representation database from 1:25K to 1:500K representation levels. At the end, a multiple representation database covering the 1:100K scale sheet extend is created. This process took 54 minutes. Now, automatic propagation of updating process from 1:25K to 1:500K is being improved. So, the final purpose that we want to achieve is to perform incremental generalization in our multiple representation database.