In: Wagner W., Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B 
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Production of True Orthophotos in Practice and Various Application Possibilities 
Hermann Novak, Martin Ulz, Ludwig Dorfstetter, Jens Schickor 
Forest Mapping Management ( FMM), 5020 Salzburg, fmm@fmm.at 
Commission VII, Symposium “100 Years ISPRS - Advancing Remote Sensing Science” 
KEY WORDS: Digital, Environment, Forestry, Mapping, Photogrammetry, Automation, DEM/DTM, Orthoimage 
ABSTRACT: 
In the last years, the demand for detailed digital surface models in Europe has increased. The sectors of energy providers and mobile 
network operators need more detailed models for better calculations and more efficient implementation. 
Forest Mapping Management GmbH (FMM) located in Salzburg, Austria, has a perennial experience in working with high- 
resolution digital surface models (DSM) and the following generation of true orthophotos. In the last 3 years, 7500 km 2 true 
orthophotos with combined DSM were generated and produced. 
The high degree of automation of the process and the reduction of insufficiencies found in normal orthophotos and results needs a 
newer way of thinking for handling such data, and provides an abundance of new possibilities. 
Since 2006, FMM developed and optimised a workflow to generate DSM and True Orthophotos, which allowed the data to be used 
by many applications, such as calculations of potential of solar collectors, actualisation of land register, documentation of damage 
caused to the environment or 3D building models and landscape-models. 
Especially in the sector of forestry and agriculture, the data has become established and is used by FMM for the development of 
software applications in the forestry sector. 
1. INTRODUCTION 2. WORKFLOW 
Because of the increasing demand of digital surface models in 
Europe and the courage for innovative solutions of questions 
and applications, FMM has begun to work with true 
orthophotos and high-resolution digital surface models for 3 
years. In these 3 years, the company made 7500 km 2 in Austria, 
especially in Salzburg, Linz, St. Polten and the Styrian region. 
Hermann Novak is leading the company with 18 employees 
since 20 years. 
Starting as a little cartographical company in the forestry 
sector, FMM has developed to a modem photogrammetric 
company with it’s own aircraft and aerial camera ( Vexcel 
Ultracam ). The newest GPS/INS technics and digital 
workstations let FMM make the basis for working with high- 
precision data and analyses. More business parts are the 
software development, including webservices for the forestry 
sector and vehicle fleet management or the production of base 
data for municipal and private applications. 
The intention of this paper is it to spark interest in the 
production of true orthophotos and digital surface models and 
to highlight their various applications. 
In the following, the process of planning and production with 
its high level of automation will be described. We will also 
demonstrate a tested application from the forestry sector. 
Finally we will try to make a look into the future of the 
production of true orthophotos and make a conclusion of the 
usage of the data now. 
2.1 Description 
Production dependa on a really good planning and flight 
execution like any high-resolution flight. The planning is the 
base for the flight and should have the flightarea covered 
completely with an 80/80 overlap. 
Often it makes sense to plan rectangular areas, because the 
overlap and the coverarea will be optimized and the following 
calculating process of the True Orthophotos will be uninfected 
by software bugs. The area should be covered in a single flight 
to avoid crossing shadows which create false interpretations in 
the automatic matching process. Generelly it is recommended 
to plan a flightarea as compact as possible. Unnecessary images 
require additional time and delay the processing of the target 
area. After the flight and the processing of the images, an 
aerotriangulation (AT) will be calculated. Here it is important to 
have a good base, especially in the height. Better tiepoint 
measurements and height precision, allow the software to make 
better matching points and are the base for a clean and good 
DSM. To make a clean AT the input data should be correct. 
That means a a high-precision cameracalibration and optimal 
measured ground control points. 
A short view of the production is shown in the following figure 
1: