# A GeoNode-Based Platform for an Effective Exploitation of Advanced DInSAR Measurements
## 4 GeoNode Modifications for the Advanced DInSAR Processing Results Integration  
We have already mentioned in the previous Section that the GeoNode platform provides two data formats for the data upload: a vector data format (Shape Files) and a raster data format (GeoTIFF), both importable through a GeoNode web interface (developed with Django). In particular, the vector data are stored in a PostgreSQL/PostGIS geodatabase table [88; 89]. Accordingly, as a step of our work, it is necessary to implement a procedure to efficiently upload the available advanced DInSAR processing results. In particular, in our case, the upload procedure takes as input the ASCII text files produced by the SBAS-DInSAR processing chain (see Figure 2), which follows the standards defined within the European Plate Observing System (EPOS) [99] of the European Strategy Forum on Research Infrastructure (ESFRI) [100]. These DInSAR data files, as shown in Figure 5, are divided in two parts: (1) an header, which contains the metadata with the general information on the applied algorithm and the parameters of the sensor from which the SAR raw data have been obtained; (2) a part which contains, in each row, the deformation time-series and the related products for each of the coherent pixels of the SAR image sequence, which are represented, in our case, by: latitude, longitude, topography, mean deformation velocity, coherence, direction cosines [99]. Note that the direction cosines allow projecting the east, north and vertical deformation components into the radar LOS direction. The uploading process is based on \"cutting\" the deformation data measurements contained in each of the text files into several portions and stored in concurrent mode into the PostgreSQL /PostGIS geodatabase tables. Therefore, the number of these tables represents the level of parallelism of the loading data process and their size varies depending on the number of coherent pixels stored in the text file. On the other hand, in order to be imported into Geoserver as a single layer, the different tables are grouped into a virtual table (view), whose relation schema is showed in Table 1. We highlight that the attribute name zYYYY_xxxx (i) in Table 1 is the \(i\)th date of the deformation time-series, where YYYY represents the year and xxxx the fraction of the year. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Attribute Name** & **Attribute Type** & **Description** \\ \hline ID & long integer & numeric identification of the pixel \\ \hline PLOT button & string & link calling a PHP module to visualize the deformation time-series, as specified in more detail later in this Section \\ \hline lat & float & pixel latitude \\ \hline lon & float & pixel longitude \\ \hline topo & float & pixel altitude \\ \hline vel & float & pixel deformation velocity \\ \hline cohe & float & pixel coherence \\ \hline \hline cose & float & east direction cosine \\ \hline cosn & float & north direction cosine \\ \hline cosu & float & up direction cosine \\ \hline zYYYY\_xxxx (1) & float & reference deformation value of the time-series \\ \hline zYYYY\_xxxx (2) & float & second deformation value of the time-series \\ \hline � & � & � \\ \hline zYYYY\_xxxx (n) & float & \(n\)th deformation value of the time-series \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Relation schema of the geodatabase table. Note that, apart from the PLOT button, the other attributes represent the products related to each coherent pixel of the deformation time-series and their deformation measurements. This uploading procedure is written in the PERL programming language [101] by using the PERL threads module [102] to speed up the process, assigning each task of table loading to a separate thread and exploiting the multi-core architecture of the modern computing systems (see Figure 6). We point out that a PERL thread is a flow of control through a program with a single execution point [103].