Defining topological relations between topographical features within the scope of 1:25000 scaled geodatabase design

1:25000 Ölçekli coğrafi veri tabanı tasarımında topografik detaylar arasındaki topolojik ilişkilerin tanımlanması

Abstract

In 1:25000 scaled digital map production system pho-togrammetric vector data is collected from stereo aer-ial photograph couples via digital photogrammetric workstations in Soft Plotter KDMS format and trans-formed into MicroStation DGN format. Some photo-grammetric editing operations (merge, clip, feature intersection arrangement, polygon closing, creating missing features, data cleaning etc.) on collected data are carried out by compilation operators via Mi-croStation Software. Then the data is transferred to completion unit for land completion works. In this unit, the operators correct the feature compilation or assessment errors, complete missing features and col-lect the attributes (name, usage purpose, feature height etc.), which cannot be detected in compilation phase, on land in 3D shape format by using digital data collection sets. The data that is collected on land are merged with the data that has been collected by compilation operators and transformed into DGN format and. Then some data quality controls are im-plemented and the data are archived in DGN format. In near feature it is planned to archive the same data also in Shape format. For the cartographic opera-tions and plotting works the data are delivered to the related units. In the data collection workflow stated above, the data arrangement operations by either compilation or completion operators mainly depend on their experi-ences. There is no written reference for these works. Because of the feature types’ excess, the complexity of relations between features and data density in a 1:25000 scaled map, it is assessed that it is very diffi-cult and time consuming even for an experienced op-erator to control the features’ relations. Thus, a need for a topological consistency control system emerges. By designing this control system it is expected that the topological consistency quality of photogrammetric vector data will increase, a valuable feedback will be available for both compilation and completion pro-cesses, topological consistency quality control of data in geodatabase, of which design and implementation works are still ongoing, will be possible, as a result of increased data quality, data queries will be more ac-curate and reliable. In this study which has been directed to improve the quality of 1:25000 scaled topographical vector data, as a part of designing geodatabase quality control system, determining and applying relations between topological features, forming relationship rules, find-ing out the data which disobey the rules and present-ing this disobeying data to operator has been aimed. “Transportation Class” features have been used for this study as a model for the whole thematic classes. At first, existing written regulations, production direc-tions and related previous studies have been scruti-nized. Some relationship rules have been determined from these references. Then numerous meetings have been arranged with experienced compilation and completion operators. The rules have been developed by means of these deliberations. After verifying that the studies have come to an end, a document includ-ing determined rules has been prepared. In this rules list it has been seen that the operators’ contribution has been much more than the reference documents’, as it had been expected. Then the rules have been ex-amined again and each of them has been decided whether it would be possible to apply to the system by using ESRI ArcGIS ready tools or it would need some customization codes. These decisions have also been written to document in related feature’s row. After-wards, the rules which could be applied by using ready tools have been defined in personal geodata-base. For the rules which have needed some scripts, the necessary programs have been prepared in ArcObjects by using Visual Basic for Applications interface of ArcMap software. These programs have provided applying these rules to the system, interac-tive data query on whole rules and presenting the dis-obeying data (errors) to the operator. Objects in the real world have very complex relations between themselves. These relations must be deter-mined and modeled as realistic as possible to be able to form the consistency of the collected data sets. Modeling the relations between topographical fea-tures in real world is a subject on which research and development studies still go on. It is assessed that with the results of this study, measurable inputs can be achieved which help deciding whether the 1:25000 scaled topographical data model and newly designed geodatabase are convenient, feasible and they can be managed or not.

Özet

Ülkemizde 1:25000 ölçekli sayısal harita üretimi sistemi kapsamında, fotogrametrik vektör veriler üzerinde, kıymetlendirme operatörleri ve bütünleme personeli tarafından fotogrametrik düzenleme-ler (birleştirme, alan kapatma, detay kesişimi, fazlalıkların atılması, eksikliklerin tamamlanması vb.) yapılmakta ve detaylar arası ilişkiler tanımlanmaktadır. Gerek kıymetlendirme operatörleri ge-rekse bütünleme personeli tarafından yapılan veri düzenlemeleri ağırlıklı olarak personelin iş tec-rübesine dayanmaktadır. Fakat 1:25000 ölçekli bir pafta içerisindeki vektör veri yoğunluğu, topla-nan detay çeşidinin fazlalığı ve detaylar arasındaki ilişkilerin karmaşıklığı göz önüne alındığında, tecrübeli personelin bile tüm detaylar arasındaki ilişkileri kontrol edebilmesinin zor ve zaman alıcı olduğu ve bu maksatla kullanılabilecek bir topolojik tutarlılık kalite kontrol sistemine ihtiyaç duyul-duğu değerlendirilmektedir. Bu çalışma ile 1:25000 ölçekli vektör veri tabanı tasarımı çalışmaları kapsamında, topoğrafik veri tabanı kalite kontrol sistemi kurulmasının bir adımı olarak Ulaşım Sı-nıfı detayları arasındaki topolojik ilişkilerin belirlenmesi, gerekli kuralların geliştirilmesi ve bu ku-rallara uymayan detayların tespit edilerek operatöre sunulması hedeflenmiştir. Bu maksatla önce-likle mevcut yönetmelikler, üretim talimatları ve konu ile ilgili eski çalışmalar incelenerek topolojik kurallar tespit edilmeye çalışılmıştır. Tecrübeli kıymetlendirme operatörleri ve bütünleme personeli ile görüşmeler yapılmış ve tespit edilen kurallar geliştirilerek yazılı doküman olarak hazırlanmıştır. Yazılı olarak hazırlanan kurallar, ESRI ArcGIS programının hazır araçları kullanılarak ve gerekli kodlar yazılarak kişisel veri tabanı ortamında tanımlanmış, hazırlanan bir arayüz aracılığıyla, kul-lanıcı etkileşimli olarak sorgulanması ve hataların ArcMap programı üzerinde kullanıcıya sunul-ması sağlanmıştır.