MARV4/2 photogrammetric inventory 2007
Published March 30, 2007 - Last modified June 2, 2007. [Index, Research, Teaching]


In 2007, the students on course MARV4/2 get familiar with photogrammetric single-tree remote sensing (STRS). The objective of the course is to make an inventory of the timber resources of a 56-hectare forest holding using both airborne and field observations..

The area is covered by large-scale digitized and digital aerial images and two sets of LiDAR observations. A sparse LiDAR data set has been processed into an accurate digital elevation model (DTM).

A method of STRS is applied in which individual trees are measured for the following STRS-variables:
  • Tree top position, XYZ
  • Height, image-based
  • Height, LiDAR-based
  • Crown width, image-based observation
  • Crown width, LiDAR-based
  • Species, visual
  • Species, image-based spectral classification
  A systematic layout of fixed-area circular plots with a radius of 11.28 m (0.04 ha) has been established in the area. A sample of these, 59 plots, was selected for measurements in the field. In the field, the photo-measured trees are identified and measured, and the missing trees - omission errors of STRS - are completed.

  The data is analysed to answer the following top-level, general questions
  • What is the accuracy of the tree-level STRS variables?
  • Can the STRS estimates be calibrated to improve their accuracy?
  • What are the timber resources in the 56-hecrate area?
  The students' role - together with the tutors - is to analyze the questions further in order to perceive the detailed questions hidden in the general questions.

1 Learning objectives
2 Study area
3 On coordinate systems
4 Airborne data sets
[Finnish: Information on aerial photographs and LiDAR in Hyytiälä]
5 LiDAR-based DTM

6 Single-tree remote sensing methods applied on the course
1 Manual photogrammetric treetop positioning and image-based measurement of crown width
2 Visual tree species intrepretation
3 Semi-automatic image-based treetop positioning using multi-scale template matching
4 Measurement of crown width by template matching
5 Measurement of crown width by adjustment of a parametric crown model with the LiDAR point cloud
6 Use of allometric models for predicting the dbh and the stem dimensions
7 Field work in Hyytiälä
1 Objective of field work
2 Mapping trees in the field using the photo-trees and a method that combines field triangulation and trilateration
3 Plot measurements
8 Office work, Viikki-Hyytiälä-Viikki
1 STRS-Labs April 18-19.
2 Field plots, forms, work instructions by groups 
3 Preparing field forms
In Helsinki, April
4 Preparing the maps and labels Helsinki, April
5 Storing data for scientific analysis
Hyytiälä, May

6 Instructions for data analysis and reporting
,  Viikki May,  14-18

Index of plot files (59) all.csv contains "everything"
Index of field forms (59)
Index of sightings (59)
Reports: Honkasalo & Ilvesniemi 23.5., Salo &
Bruun 4.6., Haapaniemi #.#., Mustonen & Suomi 24.5.,
Schäfer & Virtanen 30.5., Kuutti & Linkosalmi #.#.

9 Data sets - bulk work done in advance
  • A systematic 50 x 50-m grid was established in the area. 
  • 224 plots were inside an area-polyline. Every 4th plot was selected for photogrammetric STRS measurements. A total of 59 plots and 5294 trees were measured and they are seen here in an aerial view (orthoview) The every-4th-rule was violated (accidently) a few times, so each plot represents an area of 0.9635 ha. Nor is the spatial pattern of the plots optimal. The measurements include trees from a buffer surrounding each plot. The measurements contain plenty of redundancy as only 41.6 % or 2206 of the 5294 measured trees were inside the 59 0.04-ha circular plots 
  • IDs of the 59 measured plots (ascii-file)
  • Photogrammetric observations of the 5294 trees in an ascii file with variables: PlotCode, TreeNumber, Species, Xtop, Ytop, Ztop,  Z_DTM, Foto_h, Lidar_h, Dcrm_Foto, Dcrm_Lidar, Dcrm_RMSE, a1, a2, a3, DistanceFromCenter, AzimuthFromCenter, InOut
  • "  "   "  in 59 files - zip-file
  • 224 files / LiDAR-based estimates on V, N, G, H and D zip-file
  • "   "    "  in one ascii-file
  • Tree maps, 59 pdf-files, zip-file
  • Tree labels, 59 pdf-files, zip-file

  • DTM with photo-trees
    DTM-with photo-trees, circles, roads and plot numbers. 1-m resolution. 1101 x 1001 m. Origin XY = 2515200, 6860350 (pixel center).

  •   Orthoimage
    Ortho-image with photo trees, circles and plot numbers. Click here for a compressed version with 4401 x 4001 pixels (0.25 cm, 2.4 MB), 1100.25 x 1000.25 m. Origin XY = 2515200, 6860350 (pixel center). Uncompressed file size 51.5 MBytes.
  • GPS observations for CentrePoles; Zip, All (54) but 163, 191, 195, 207, 219. New stuff
10 Programs