This document discusses modelling forest height from TanDEM-X and lidar data. Small footprint lidar data at 0.5 m resolution was used to model forest height maps created from TanDEM-X data. A two-layer model is presented that models the TanDEM-X height as a function of the lidar height data using parameters like the height of ambiguity. Plots show the modelled height matches the TanDEM-X height for different heights of ambiguity.

1. 0
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10
15
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Height[m]
MODELLING OFTANDEM-X MEASURED FOREST
HEIGHT FROM SMALL FOOTPRINT LIDAR DATA
TanDEM-X (TDM) forest height map =
TanDEM-X DEM – HiRes* DTM*grid: 2 m x 2 m, mean error < 0.5 m
ACKNOWLEDGEMENTS
This work was financially supported by the Swedish National Space Board (SNSB). TDM
data were provided by German Aerospace Center (DLR). DEM was provided by Swedish
Land Survey. Lidar data were acquired within the ESA BioSAR 2010 campaign.
Maciej Jerzy Soja1) and Lars M. H. Ulander1,2)
1) Chalmers University of Technology, Gothenburg, Sweden
2) Swedish Defence Research Agency, Linköping, Sweden
CONTACT
Department of Earth and Space Sciences
Chalmers University of Technology
SE-412 96 Gothenburg, Sweden
E-mail: maciej.soja@chalmers.se
Internet: www.chalmers.se/rss
Effect of forest sparseness at low HOA*
*HOA = height of ambiguity
Modelling TDM height from high resolution lidar height data (0.5 m x 0.5 m)
: 𝛾� =
∑ exp 𝛼+𝑖𝑘 𝑧 ℎ
∑ exp 𝛼𝛼
𝛼 = 0.01
ℎ =
arg 𝛾�
𝑘 𝑧
Two-layer model
𝛾� = exp 𝑖𝑘 𝑧Δℎ + 𝜇 1 + 𝜇⁄
𝐻𝐻𝐻 =
2𝜋
𝑘 𝑧
=
𝜋𝜋 sin 𝜃
𝐵⊥
ℎ 𝑚𝑚𝑚
𝐻𝐻𝐻
= tan−1
sin
2𝜋Δℎ
𝐻𝐻𝐻
𝜇+cos
2𝜋Δℎ
𝐻𝐻𝐻
2𝜋�
0 2 4 6
-0.5
0
0.5
1
1.5
HOA/∆h
hmod
/∆h
µ=0.01
µ=0.10
µ=0.50
µ=0.95
µ=1.05
µ=2.00
µ=10.00
µ=100.00
0
5
10
15
20
25
30
35
Height[m]
Modelled h (HOA=49 m)
Modelled h (HOA=37 m)
TDM h (HOA=49 m)
TDM h (HOA=37 m)
1
9
Plot 9: photo and
lidar (below)
𝐵⊥
𝑅 𝜃