# Geovisualization Techniques of Spatial Environmental Data Using Different Visualization Tools
## 5 Conclusions  
Our study provided a method showing how the QGIS geovisualization modules and KML tools can be applied to publish geospatial information on the Internet. In order to demonstrate this, we depicted the nitrate and phosphate contamination of a settlement located in East Hungary. We investigated the spatial and temporal distribution of the contamination, as well as its changes. Using the created point and interpolated maps we were able to determine the most contaminated areas of the settlement which were the central part of the settlement in the case of phosphate, and the zone located to the south of the central part of the settlement in the case of nitrate. Having investigated the differences between the assessments made before the construction of the sewage system (2013) and after the construction (2019), we concluded that significant positive changes can be observed in the case of both contaminants. In the case of phosphate, the spatial distribution remained the same; however, the concentration of the wells significantly decreased. In the case of nitrate, the most significant decrease in concentrations was observed in the central parts of the settlement, while the rate of decrease of the concentration was lower in the most contaminated parts. The open-source geovisualization tools clearly demonstrate that tools derived from geoinformatics can enhance the cognition of the data which geographers work with. The opportunities presented by visualization techniques can be used for the visualization of different spatial environmental databases, thus broadening the amount of displayable information and helping the cognitive interpretation of spatial data. The spatial environmental data used are representative in  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & **Contamination** & \multicolumn{2}{c}{**Mean**} & \multicolumn{2}{c}{**Minimum**} & \multicolumn{2}{c}{**Maximum**} \\ \cline{3-6}  & **Limit (mg/L)** & 2013 & 2019 & 2013 & 2019 & 2013 & 2019 \\ \hline
**NO3\({}^{-}\) (mg/L)** & 50 mg/L & 187.8 & 163.5 & 8.36 & 7.61 & 564.8 & 6455 \\ \hline
**PO4\({}^{-}\) (mg/L)** & 0.5 mg/L & 1.22 & 0.49 & 0.07 & 0.04 & 4.07 & 214 \\ \hline
**Parameters** & **Contamination** & **Lower Quartile** & **Upper Quartile** & **St. Deviation** \\ \cline{3-6}  & **Limit (mg/L)** & 2013 & 2019 & 2013 & 2019 & 2013 & 2019 \\ \hline
**NO3\({}^{-}\) (mg/L)** & 50 mg/L & 50.16 & 43.09 & 341.7 & 244.8 & 164.4 & 170.7 \\ \hline
**PO4\({}^{-}\) (mg/L)** & 0.5 mg/L & 0.374 & 0.137 & 1.75 & 0.604 & 1.09 & 0.49 \\ \hline \hline \end{tabular} The red and green cells indicate values above and under the contamination limits, respectively.  
\end{table}
Table 2: Descriptive statistics of investigated parameters.  
themselves; however, by combining these techniques and publishing, we were to assess nitrate and phosphate values and their spatial configuration from a new perspective.  
Conceptualization, D.B. and T.M. methodology. D.B.; T.M.; G.K.; E.K. software, D.B.; G.K.; R.T. and M.Z. validation, D.B.; T.M.; E.K.; G.K. and M.Z. formal analysis, D.B. investigation, D.B. and T.M. resources, D.B. data curation, T.M. writing--original draft preparation, D.B. writing--review and editing, D.B. visualization, D.B.; G.K.; R.T. and M.Z. supervision, D.B.; T.M. and M.Z. project administration, D.B. funding acquisition, D.B. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
This work was supported by the construction EFOP-3.6.3-VEKOP-16-2017-00002. The project was supported by the European Union, co-financed by the European Social Fund.  
The authors declare no conflict of interest.