# From Google Earth Studio to Hologram: A Pipeline for Architectural Visualization
## 2 Materials and Methods
### Extracting Image Data from Google Earth  
Following the selection of suitable structures for the experiment, the next phase involved the extraction of image data using Google Earth Studio. This process began by configuring a workspace with a width and height of 1320 and 1760 pixels, respectively. The frame rate was set at 60 fps. Subsequently, the optimal field of view (F) was selected to effectively capture the structure and define a fixed camera target. In Earth Studio, the camera target ensured consistent focus on the intended subject throughout the animation. For holographic data acquisition, the target was typically positioned at the geometric center of the structure, corresponding to the final reconstruction plane of the hologram.  
A total of 13 key viewpoints were used to define a 120\({}^{\circ}\) arc and their corresponding coordinates were entered into Google Earth Studio to generate the camera path for rendering. Each key point was spaced 60 frames apart, resulting in 721 rendered frames that satisfied the quantity required for CHIMERA hologram printing. Notably, when the camera transitioned between key points in Earth Studio, it followed a linear trajectory rather than a smooth arc. As a result, although the intended path formed a 120\({}^{\circ}\) circular arc with key viewpoints spaced at 10\({}^{\circ}\) intervals, the actual camera motion occurred in straight-line segments, causing slight variations in the distance (r) between the camera and target point (Figure 3).  
Nonetheless, this deviation had a minimal impact on the resulting image data. Given the relatively small angular separation between key points, the variation in distance was imperceptible to the human eye and did not affect the quality of the holographic reconstruction.  
All 13 key viewpoint coordinates in Google Earth Studio could be calculated based on the camera target coordinates and radius (r), which was the distance between the camera target and all key viewpoints. Using the coordinates of the camera target, that is, latitude--\(Lat_{t}\), longitude--\(Long_{t}\), and altitude--\(Alt_{t}\), along with the radius (r) from the camera to the object, Equations (2) and (3) were applied to compute the latitude (\(Lat_{x}\)) and longitude (\(Long_{x}\)) of each camera key point. The altitude (\(Alt_{x}\)) of all key points could be set flexibly based on the different circumstances of the area surrounding the recording objects, which implies that all key points had the same selected altitude.  
\[\begin{split}& If\ 90\leq x\leq 270,\ then\ Lat_{x}=Lat_{t}+\left(r* sin\frac{90-A_{x}}{111139}\right)\\ & If\ not,\ then\ Lat_{x}=Lat_{t}-\left(r*sin\frac{90-A_{x}}{111139} \right)\end{split} \tag{2}\]  
\[\begin{split}& If\ x\leq 180,\ then\ \text{Long}_{x}=\text{Long}_{t}-\left(\frac{r* sin\,A_{x}}{111320*\text{cosLat}_{x}}\right)\\ & If\ not,\ then\ \text{Long}_{x}=\text{Long}_{t}+\left(\frac{r* sin\,A_{x}}{111320*\text{cosLat}_{x}}\right)\end{split} \tag{3}\]  
Here, x is the key viewpoint of the camera position on the Google Earth Studio navigation circle, ranging around the camera target. For example, if the corresponding 120\({}^{\circ}\) sector extends from 260\({}^{\circ}\) to 20\({}^{\circ}\), then the 13 key viewpoints are 260\({}^{\circ}\), 270\({}^{\circ}\), 280\({}^{\circ}\), 290\({}^{\circ}\), 300\({}^{\circ}\), 310\({}^{\circ}\), 320\({}^{\circ}\), 330\({}^{\circ}\), 340\({}^{\circ}\), 350\({}^{\circ}\), 0\({}^{\circ}\), 10\({}^{\circ}\), and 20\({}^{\circ}\) (Figure 4). Additionally, \(Lat_{x}\) is the latitude of the key viewpoint (x), \(Long_{x}\) is the longitude of the key point (x), \(A_{x}\) is the altitude of the key viewpoint (x), \(Lat_{t}\) is the latitude of the camera target, \(Long_{t}\) is the longitude of the camera target, and r is the distance between the camera points and the camera target/radius of a 120\({}^{\circ}\) arc.  
Figure 3: Linear movement of camera between key viewpoints on the camera’s path in Google Earth Studio project.