# Mapping with Pleiades--End-to-End Workflow
## 3 Test Sites and Data Sets  
To allow sophisticated statements on Pleiades-based mapping, several test sites have been selected. They represent different acquisition dispositions in terms of viewing angles, stereo, triplet and multi-stereo constellations, cover different types of terrain and originate from both Pleiades-1A and 1B sensors. The test sites are located in Austria, Italy, Slovenia, Singapore and China. For the core investigations, three test sites were used, for which both representative Pleiades acquisitions and appropriate reference data sets are available. The data from Singapore must not be published, thus no screenshots of this test site are presented in this work. Overall, 24 Pleiades images are used in this study, with acquisition dates and main acquisition parameters as listed in Table 1. Images are also assigned with an ID such that referring to a specific image gets simpler. When talking about a stereo model it is addressed as two IDs, like model 1-2.  
For assessment of the 2D and 3D geo-location accuracy reference GCPs are needed. In the optimal case, these points are measured with in-situ highly accurate devices, such as differential GPS. This was done for the test site Singapore. Alternatively, existing orthophotos with higher spatial resolution can be used to manually define the GCPs where the height information is taken from the LiDAR reference. This was done for the test site Ljubljana. In other cases, airborne LiDAR information is used to derive GCPs. There, distinctive locations, especially at 3D breaklines, are manually measured (for instance, a corner of a roof top or a hydrant). Obviously, as the LiDAR DSMs are available with 1 m GSD those manually measured objects will never get the accuracy as the in-situ or orthophoto measurements. This has to be kept in mind when comparing the accuracy values, as the accuracy of the reference information is the lower bound for the resulting geo-location accuracy.  
The multitude of test sites were chosen to demonstrate that the proposed end-to-end workflow allows precise 3D mapping over the whole globe and is able to operate with different reference data and multi-stereo dispositions.  
Since the incidence angles of Pleiades images are given for across track (roll, \(\omega\)), for along track (pitch, \(\phi\)) and for the combined overall angle, we derive equations to calculate the stereo intersection angle \(\delta\) (also called the convergence angle [42]) between two Pleiades scenes and accordingly an approximation of their base-to-height (\(\mathrm{B}/\mathrm{H}\)) ratio. Thus, we first define the two vectors \(r_{1}\) and \(r_{2}\) and second they are used to compute \(\delta\) and \(\mathrm{B}/\mathrm{H}\) as  
\[\delta=\arccos\left(\frac{r_{1}\cdot r_{2}}{|r_{1}|\cdot|r_{2}|}\right)\quad \text{and}\quad\frac{B}{H}=2\cdot\tan\frac{\delta}{2}\quad\text{with}\quad r_ {1}=\begin{bmatrix}\tan\phi_{1}\\ \tan\omega_{1}\\ 1\end{bmatrix}\quad\text{and}\quad r_{2}=\begin{bmatrix}\tan\phi_{2}\\ \tan\omega_{2}\\ 1\end{bmatrix}\,. \tag{1}\]All convergence angles within this work are determined using Equation (1), especially the ones given in Tables 1 and 2.