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Feedback on Scanning and
Orthophoto Generation
3rd June 2019
Workshop on Geoprocessing and
Archiving of Historical Aerial Images
Víctor J. García MoralesEngineer in Geodesy and Cartography
Company Profile
Founded 1982
Expertise in Cadastre
Founding objective of assisting the Government of Navarra in the creation and
establishment of the Cadastre of Navarra
TRACASA Today Share Capital: 21,2 M€ Revenue 2018: 24,70 M€
Annual R&D Budget: 0,8 M€ Employees: 458
TRACASA is a government owned company, from the Navarra
Autonomous Region of Spain. Owned by the Government of Navarra
Government owned
Company
Business Units
GIS Solutions and
Cartography
Information System
Development and
Cadastre
Territorial Information Systems and Cartography (TIS)We work for government agencies and companies in the utilities industry developing tailored
solutions based on the specific needs of our clients, using Graphic information Systems Technology.
The SIT Business Unit complements its service offering developing Remote Sensing solutions working
with aerial sensor technologies for our clients in the environmental engineering industry and a full
range of Cartographic Production Services
Software Engineering and Information Systems and Cadastre (ISSI)We design, develop and deploy solutions working with Government Agencies, helping them deliver
improved and more efficient public services through the implementation and use of information
Technologies, we conduct Cadastral Surveying Projects and Land Management and Administration
projects in the Rural Sector
Navarra, just a step away from the world
Navarra Area: 10,391 km2 …maybe you know Navarra!
Where we belong…
An image is worth a thousand words
Historic aerial imagery offers an insight into the past.
Contents
Feedback on Scanning and Orthophoto Generation
- Aerial imagery Archive
- Scanning Methodology
- Ortophoto Production Methodology
- Applications
Archive of Navarra’s Government
1966 Navarra was in charge of its own cartographic
production, need for aerial imagery.
- More than 150.000 aerial images
- Negatives: cut or roll film
- Positive
- Color and B/W
- From 1927 – 2006
- Controlled: Temperature and humidity
Scanning the past - Archive
Scanning the past
Objective of the scanning:
- Preserve historical and irreplaceable information
>50 years, problem of conservation
- Priority: Older information and not proper conserved.
- Applications
- Orthophoto
- Web catalog
- Other products
Experience scanning
40% Archive is already scanned (Roll film and small part of the cut film)
Analog images scanned
- From 1996 till 2006: 60.000 Negatives scanned.
- After 2006: Historic areal imagery: 60.000 Negatives scanned.
Main scanning projects:
- 1927 – 1934: Navarra (10.000), Murcia (6.000), Álava (3.000)
- 1966 – 1967: Spanish National coverage: Navarra (2.000)
- 1987 – 1991: Navarra Cartographic production (7.000)
- 1992 – 1996: Navarra Upgrade cartography (7.000)
Scanning the past
Equipment:
Intergraph PhotoScan TD (1) 1996
Vexcel UltraScan 5000 (2) 1999/2000
Leica DSW600 (1) 2003 upgraded DSW700 v29 2018
Scanning the past - Scanner
Automate the scanning process:
Scanning the past - Scanner
Rebuild the roll film:
Vexcel UltraScan 5000
Any filmroll scanner
Scanning Methodology
1.- Analyse the analog images, to know the real status of
conservation.
2.- Create groups of images with similar characteristics,
belong to the same flightline.
3.- Pre-Scan at least one image to determine scan
parameters per group.
Scanning Methodology
4.- Cleaning: Removal of dust and other particles.
Scan room is clean and well ventilated.
Negatives are handled with lint-free gloves.
- Manually: If the negatives are cut
5.- Filmroll reconstruction (if it is possible)
- Automated: Roll film cleaning and neutralising electrostatics
6.- Scanning process: Set system parameters
Scanning Methodology
7.- Quality Control:
- Statistics 8/16 bits
- Direct Validation (saturation <5%,
wide dynamic range)
- Visual inspection: 1 or 2 per scan group
5-10% Project
New scan: Changing individual parameters. New pre-scan.
• Reducing the size of the patch window
• Deep clean
• Time exposure
• Change light parameter
MaxValue MinValue Mean Median Mode Standard Deviation Dinamic Range
4013 82 2016,07 1954 1135 824,37 3509
Scanning Methodology
8.- 16 to 8 bits conversion: Automatic process or define a
conversion for each group.
New QC 8bits images
9.- Database creation
- Flight metadata (Scan resolution, focal length, camera,…)
- Statistics
- Any comment related with the status
Scanning Methodology
10.- Georeferencing: Find an approximate location and
orientation for each image.
- Manually: One by one. Reference orthoimages. More
accurate – Slow / Individual images– Not always possible.
Dependency of other images from the same flight.
- Existing Flight plan: Georeference and use the photo shoot
mark to determine the centre of the image (XY)
- Relative orientation of group images: Measure minimum GCP
to georeference all the images. Low accuracy.
Scanning the past
Year A/DFlight
scale
Resolution
(microns)
GSD
(cm)
Scan
dateScanner
1927 - 1934 A 1/15.000 20 2005 Vexcel US 5000
1945 A 1/40.000 10 Unknown Digital images provided
1956 A 1/35.000 25 Unknown Digital images provided
1966 A 1/17.500 20 2009 Vexcel/DSW600
1982 A 1/20.000 15 2012 DSW600
1991 A 1/70.000 21 1996 Photoscan TD
1987-1991 A 1/20.000 15 2018 DSW600
1992-1996 A 1/20.000 15 2019 DSW700
1998 A 1/20.000 21 2000 Photoscan TD
2000 A 1/20.000 21 2000 Photoscan TD
2003 A 1/20.000 20 2003 Vexcel US 5000
2004 A 1/18.000 20 2004 DSW600
2006 A 1/18.000 13 2006 DSW600
2008 D 22
2009 D 22
2010 D 22
2011 D 22
2012 D 22
2013 D 22
2014 D 45
2017 D 22
2018 D 33
2019 D 33
Navarra whole Coverage:
Orthophoto Production
Navarra whole Coverage:
Year A/D Flight scaleResolution
(microns)
Ortho
(cm)Ortho date
1927 - 1934 A 1/15.000 20 25 2018
1945 A 1/40.000 10 45 2017
1956 A 1/35.000 25 100 2006
1966 A 1/17.500 20 40 2017
1982 A 1/20.000 15 30 2012
1991 A 1/70.000 21 187,5 1998
1987-1991 A 1/20.000 15 30 -
1992-1996 A 1/20.000 15 30 -
1998 A 1/20.000 21 42 2000
2000 A 1/20.000 21 42 2001
2003 A 1/20.000 20 40 2004
2004 A 1/18.000 20 40 2005
2006 A 1/18.000 13 25 2007
Wild C2
1927-1934: Methodology Orthophoto Production
Julio Ruiz de Alda
Military Pilot
Was born in Estella (Navarra)
During 1927 – 1934
https://wildstiften.ch/wp-content/uploads/2015/11/history_poster_pos_2010_en.pdf
- Total images: 10.000 (7.150 km2 aprox. 70% of Navarra)
- Purpose of the flight: Cadastre and Hydrology (River Basin)
- Camera used: Unknown. We assume Wild C2 (Focal length 165 mm)
- Original size: 10x15 cm (negative not available)
- Negative size: 20x30 cm (double size)
- Scanner: Vexcel UltraScan 5000. Manually scanned, 20 microns. 1 year 2007.
1927-1934: Methodology Orthophoto Production
Digital Images ATOrtho
RectificationMosaic
- Initial Exterior Orientation Parameters
- Approximate georeferencing:
- Location of each image was known approx.
- The Kappa angle was known approx.
- GSD: 10 - 20 cm.
AT Block per Cadastral Polygon (33 Polygons):
- Interior Orientation: No camera Information. Workflow = Digital Images
- Relative Orientation: Photogrammetric SW No able to obtain Tie Points
- Import Tie points from other SW: Extraction with Pastis – MicMac and other SW
- Absolute Orientation: No easy to find GCPs with accurate XYZ coordinates.
- Measured 50 GCPs per block.
- RMSE: 50 microns – 2.5 pixel – Less than 1 meter.
- New calculation adjacent block to reduce the number of AT blocks
1927-1934: Methodology Orthophoto Production
Digital Images ATOrtho
RectificationMosaic
- New block distribution to reduce differences.
- Digital Elevation Model for Orthorectification
- Creation of DTM stereo correlation.
- Gaps completed with existing Z information: Old contours lines,
existing DTM
- Orthorectification: 25cm pixel size.
1927-1934: Methodology Orthophoto Production
Digital Images ATOrtho
RectificationMosaic
- Before the creation of the final product: Improved the XY final accuracy.
- Image registration using the most accurate image: Churches, old buildings.
- Mosaic the orthorectified images, radiometric balance.
1927-1934: Methodology Orthophoto Production
Digital Images ATOrtho
RectificationMosaic
- SDI Website
- FTP download Orthoimages
- Individual aerial images
- Web Catalog
1927-1934: Methodology Orthophoto Production
https://cartotecayfototeca.navarra.es/cartoteca/
https://idena.navarra.es/navegar/
Applications
- Define boundaries
- Cadastre/Urbanism: exact definition when a building was built
- Ancient Cattle Roads
- Hydrography:
- Changes of the river bed
- Creation of DEM (Reservoirs)
- Multitemporal analysis:
- Quarries
- Evolution Urban Areas
- Land Use
The need of scan historical archive: Bad conservation,
looses of irreplaceable information.
Scanning process:
10% Scan – 90% rest
Reduce number of Photogrammetric Scanner
Importance of Georeferencing and AT to create
measurable products to perform analyses
Final remarks
Feedback on Scanning and
Orthophoto Generation
Víctor J. García MoralesEngineer in Geodesy and Cartography
Any question?