Projects / Programmes
Kombinirani visokoločljivostni postopki zajemanja, razpoznavanja in vzdrževanja prostorskih podatkov (Slovene)
| Code |
Science |
Field |
Subfield |
| 2.17.00 |
Engineering sciences and technologies |
Geodesy |
|
| Code |
Science |
Field |
| 2.07 |
Engineering and Technology |
Environmental engineering
|
Researchers (20)
Organisations (4)
Significance for science
Remote sensing technology in the field of aerial-survey, satellite imagery and laser scanning is developing toward better space and radiometric resolution, more accurate direct georeferencing, economical data collection and simultaneous use of different sensors.
Combining data from different sensors for automatic and semiautomatic procedures won recognition in some areas, while for extraction of topographic data it was only partly successful. The problem of using automatic and semiautomatic procedures for updating topographic databases is in a large number of object types which need to be recognized and collected. Each data object in a topographic database also consists of several attributes which are difficult or even impossible to interpret by automatic procedures.
Main time saving with automatic and semiautomatic procedures is achieved by initial collection of geometric data into a topographic database and the use of change detection for updating. In initial data collection by automatic procedures is important to get geometric data as much as possible. During change detection one needs to compare existing database with new data and find differences showing real changes of topographic objects.
In the project some procedures have been tested, which brought new experience about using combination of data from different sensors. Most promising combination for updating topographic databases was combining aerial-imagery and laser scanning data with automatic extraction of basic object types.
Results of the research project contribute to successful completion of learning processes for some of involved researches and stimulate new research tasks in this area.
Completed research tasks are important for international development activities and discussions about assessment of product from aerial-survey, satellite images and laser scanning, when considering different natural and technical conditions as state-of-the-art source for collecting topographic data and maintain topographic databases.
Significance for the country
National Topographic Database at the 1 : 5.000 scale (DTK5) is completed at 60%. Updating of existing DTK5 sheets is very slow. Updating of National Topographic Database at the 1 : 25.000 scale has stopped, which is why the only national wide Topographic database is at the 1 : 50.000 scale.
Sectorial databases are updated independently, therefore this usually leads into unmatched geometry when we try to analyze the data from different sectorial databases together. Most of sectorial databases are updated using orthophoto, which is metrically correct only for topographic objects lying on the ground level. Topographical objects which extend above ground level are mapped on the orthophoto with a location error because the orthophoto is produced from aerial-survey images using Digital Terrain Model (DTM), which does not include high objects. Location error also depends on aerial-survey angle, which vary between different Cyclic Aerial-survey of Slovenia (CAS).
As chosen combination of data source for updating topographic databases we propose to Survey Mapping Authority of Republic of Slovenia (SMARS) to collect and distribute aerial-survey imagery and data from laser scanning. With those data source the continuation of CAS is assured, while laser scanning data helps to improve height component of DTM, which is required by many applications. Data from laser scanning also helps with change detection, which is very important for updating topographic databases.
Automatic and semiautomatic procedures have been partly developed for detection and collection of topographic objects to fill up 40% of empty sheets of DTK5. For successful updating of existing 60% of the sheets, automatic and semiautomatic procedures for change detection of topographic object types can be used.
Technical specification has been written for CAS and Aerial Laser Scanning (ALS) on the national level and it needs to be improved and complemented with new experiences and requirements before each new cycle of source data collection on the national level. In smaller areas aerial-survey and laser scanning are also preformed for national and local requirements without use of detail technical specifications and without proper quality control. There is still much to be done on quality control of source data collection.
In the frame of research project some technical, organisation and financial directions have been set for updating of topographic databases:
Technical directions:
- to agree which topographic databases (e.g. at the 1 : 5.000 and 1 : 50.000 scales) have to be updated on national level need,
- it would be advisable to divide the county in three areas based on intensity of development, where details of topographic data would be collected accordingly (e.g. towns at the 1 : 2.500 scale, rural areas at the 1 : 5.000 scale and at the 1 : 10.000 scale for large forests and alpine regions),
- to define layers and object types for each of mentioned scales,
- to define other space databases (building cadastre, land use, road databases…) which can be connected or be even part of topographic databases and can be used for common updating,
- to define updating cycle for certain scales,
- to define cycle for source data collection based on updating cycle,
- to develop more applications where topographic data is used.
Organisation and financial directions:
- to connect ministries and large topographic data consumers who could finance topographic data collection and updating together,
- to connect ministries and large topographic data consumers who could answer questions from technical part together,
- to set up the legal basis for managing organisation and financial matters for updating of topographic databases,
- to develop marketing for topographic databases or budget financing for updating purposes.
Most important scientific results
Final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Final report,
complete report on dLib.si
