Volume Control of a quarry GEOBIT (from January 2004 until January 2005)

1. Volume Control of a quarryGEOBIT(from January 2004 until January 2005) Eng. Vasco Palmeirim

2. Introduction • I represent GEOBIT, a Portuguese Private Company, which is a Photomod dealer. We have also Production Departments which deal mainly in GIS and Mapping . • The purpose of this document is to give an example of the power of Photomod software, showing how Geobit uses PhotoMod in Map Production. • The following case will demonstrate the use of Photomod tools for Volume Control in a Quarry.

3. Quarry location The quarry is located about 10 Km North of Lisbon, Capital city of Portugal

4. Aerial Photographs · Maximum 1/4000 photo scale · Raster maximum of 15 micron · File format : TIFF, 24 bit color pixel ·  60% overlap Global Orthophotomap · Scale 1:1.000 · File format : TIFF, 24 bit color pixel · Pixel size : 0,20 m · Planimetric Precision : 0,20 m Global 3D Vector file · Scale 1:1.000 · File format : Autocad 2000 binary DWG · Planimetric Precision : 0.1 m · Only 1 Map of the whole area · Planimetric Details: Buildings, Road, Walls Slopes, Water lines, … · Contour lines every 1 meter Volume Calculations · Earth movements between: January 1st, 2004 and April 1st 2004 April 1st 2004 and July 1st 2004 July 1st 2004 and October 1st 2004 October 1st 2004 and January 1st, 2005 · Volume Precision : Better than 1% Detailed specifications

5. Project Planing With these parameters set by the client, we planned our production line as follows: 1.Aerial photography 2. Scanning of aerial film 3. Ground Control Points (GPS) 4. Aerotriangulation 5. Stereo vector data acquisition of planimetry 6. Stereo tin data acquisition 7. Orthophotomap production 8. Map creation with all details and contours 9. DEM creation 10. Volume calculation

6. Aerial photographs The aerial photographs had the following characteristics: • 5 flights were done: January 2004, April 2004, July 2004, October 2004 and January 2005 • Focal length of 153 mm • Average scale 1 : 3500 • Color • nearly East / West

7. Scanning For this phase, we used a UltraScan 5000 photogrammetric scanner, produced by VEXCEL. As a standard, we use 15 micron pixel size, with 24 bit color per pixel in TIFF raster format file.

8. Ground control points (1) Field work was specially planned, so that the Ground Control Points observed in the first aerial photographs could be also used in the photographs, that had to be made every 3 months. Points that were going to be difficult to be recognized in newer aerial photos, such as stones, were painted white on the field with Special All-weather Paint. This decision was very useful in all the new photos that were taken every 3 months.

9. Ground control points (2) Because ground detail made it difficult to choose good GCPs, many of these points were subdivided in 2 or 3 neighboring points. During fieldwork, we used SOKKIA GPS GSS1 2 band receivers (static mode) recording satellite data every 5 seconds during a minimum of 10 minutes. Coordinates were calculated with post-processing software by Sokkia, thus achieving better than 1 cm precision.

10. Aerotriangulation • Importing images The image represents an Overall View after aerotriangulation, in Photomod’s Montage Desktop. • Introducing GCP data files ( X, Y and Z ) Aerotriangulation followed the usual sequence in PhotoMod AT module: • Introducing data from aerial • camera calibration certificate • Fiducial • measurements for • internal orientation • Correlation points for • relative orientation • GCP image measurements • Aerotriangulation computation Computation results were rms 0.023 m for XY and 0.031 m for Z

11. Data acquisition with StereoDraw(1) ... We vectorized all planimetric details, such as: Roads Buildings Walls Fences Posts Lakes Rivers Slopes Ridges Bridges etc... In this phase, we used StereoDraw module, with a complete code table to classify all objects during data acquisition.

12. ... Data acquisition with StereoDraw(2) ... With every new aerial photographs, we only had to import the ‘old’ data and make the necessary adjustments. Checking old contours in the new photographs, were the best tools we had to locate the areas where the surface had been changed. This work was mainly done with the first aerial photographs taken January 3rd, 2004. New photo and old contours New photo and updated contours

13. ... Data acquisition with StereoDraw(3) Every 3 months, with the new photos, we only needed to scan the new images, create a new project, aerotriangulate and create new epipolar images. This means, that updating 3D vectorial data was very simple, using the StereoDraw module. New photo and old contours New photo and updated contours

14. Data acquisition with DTM (1) ... From StereoDraw data, we only extracted 3D data which correctly defined earth surface, such as: • Water lines, lakes, rivers … • Break lines (slopes, ridges …) • Roads, bridges … Starting DTM module, we: • Imported VEC files • Created TIN with objects • Built the break lines into TIN • Introduced extra points and lines • Viewed and edited TIN triangles • Generated contour lines For the new aerial photographs, we always used the updated contours for TIN generation, later for DEM creation and in the end, for orthophoto production.

15. ... Data acquisition with DTM (2) ... This work was only done with the first aerial photographs taken January 3rd, 2004.

16. ... Data acquisition with DTM (3) Below is an example of generated contours:

17. Orthophotomap production Below is a small example of the generated orthophoto: With the final TIN, we started MOSAIC module, and defined the parameters of the Orthophoto

18. Creation of a global drawing with all planimetric data Using special tools, Map cleanup was made, in order to guarantee that: All planimetric and height data created were joined in only one drawing 1- All buildings were closed 2- Continuity of road lines 3- There were no duplicated objects

19. DEM Creation (1) ... The locations were identified when comparing ‘old’ contours ( 3 months old ) with the new photos in StereoDraw module. In Montage Desktop, DEM was created. In this example, the parameters were: Cell size 1m, adjusted coordinates to 1 meter in South and West limits This phase was done only in the areas where surface was modified.

20. ... DEM Creation (2) Example of DEM export as CSV file

21. Volume calculation (1) ... All Points, outside the area of study, were erased. With another Lisp program, we calculated the volume of that area. DEM data was exported as CSV files. After, inside AutoCad or Cadian, we used LISP program to read the CSV file and create 3D Points. For volume calculationwe repeated the same steps for the same area but with the CSV file created from the older DEM.

22. ... Volume calculation (2) In this detailed image, it can be easily seen, that each point has precise meter coordinates, and the boundary has a 50 cm shift in X and Y direction, in relation with all the points.

23. Final Notes The 3.7 and 3.8 Photomod versions we used, are very powerful tools for Map Production, even with very precise technical requests from our clients. We must remember, that this paper does not refer many other potential applications that Photomod software modules can do. Geobit wants to use this opportunity to congratulate Racurs and all their workers, for the excellent software development that they have been producing during these last years.