# Systematic Mapping Study on Remote Sensing in Agriculture
## 4 Discussion  
### Main Findings and Implications for Researchers and Practitioners  
The ultimate purpose of the study is to gain an in-depth understanding of the current state of research in remote sensing in agriculture, in order to give suggestions about future lines of research and finding new possibilities and application areas. This is achieved by an analysis and discussion of the results presented in the previous section. The major findings that can be extracted are the following. * The main publication channels of the selected papers are journals, at a great distance from books and conferences. This is caused by the introduction of the strict exclusion criterion EC2 of six citations per year. Publications in journals are known to be cited more than those in conferences. Although conferences are important publication venues for computer science researchers [205], the research community tends to prefer publishing in journals due to the tenure and promotion guidelines in many institutions which only consider publications in high-impact factor journals [206]. However, the role of conferences as a means of spreading new ideas, showing ongoing research and connecting researchers should not be dismissed. * The research field of RSA has gained an increasing interest since the beginning of the millennium. This can be explained by the new technologies that appeared in this period (cameras, satellites, and UAVs) in addition to the improvements in telecommunications and data transmission. The decrease of publications observed in 2019 is a collateral effect of the review procedure \begin{table}
\begin{tabular}{l l l} \hline \hline
**Spectral Information** & **Ref.** & **Total** \\ \hline RGB (visible spectrum) & [79,91,95,104,110,111,113,115-118,121,122,125,126,130,132, \\  & 140,142,145,147,148,150-152,160-162,164,165,169,171,176, \\  & 178–180,182–184,186–188,190,192,193,199] \\ Hyperspectral (narrow band) & [91,96,104,108,112,118,123,127,134,137,141,143,144,146, \\  & 153,155–157,168,170,177,194–196,198,200,201,203] & 28 \\ Long-wave infrared (thermal) & [141,101,106,107,124,131,135,136,138,141,151,155,164–168, \\  & 172,177,189,193,197] & 22 \\ Near infrared (NIR) & [116–118,121,130,133,134,142,145,151,158,181,186,193] & 14 \\ Multispectral (broad band) & [114,129,139,146,149,154,159,163,171,173,197,200,201] & 13 \\ Red edge spectrum & [101,104,119,128,132,142,158,160,181,185,188,191] & 12 \\ Synthetic aperture radar (SAR) & [79,104,120,121,126,183,202] & 7 \\ Light detection and ranging (LiDAR) & [92,108,148,174] & 4 \\ Short-wave infrared & [117,121] & 2 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Classification of types of spectral information used in RSA research. and the minimum required number of citations. Thus, the increasing interest in RSA is expected to continue in the near future, favoring the appearance of new journals and conferences more specialized in the different areas of RSA. * Most of the selected papers are evaluation research using data sets. Solution proposals represent almost one-third of the selected papers, which indicates that the field has reached a certain maturity and researchers are more interested in evaluating existing technologies rather than proposing new ones. This is also supported by the large number of reviews identified. On the other hand, this highlights the importance of creating public and comprehensive datasets where the results of different authors can be compared. It would be recommended that this effort be carried out by existing institutions and associations, rather than particular research groups.