Thanks to your supports and interests, I could successfully complete the research project and publish the results in an academic journal, Landscape and Urban Planning. You can see the outcome of your contribution here at  http://www.sciencedirect.com/science/article/pii/S0169204617301469?via%3Dihub .

This is an excerpt from the paper:

With a systematic observation tool, SOPARC (System for Observing Play and Recreation in Communities), this study finds that the UAV observations show a high level of inter-rater reliability (ICC =0.99 for a total number of users). In addition, compared to the results of on-the ground observations using SOPARC, those of UAV observations demonstrate validity (ICC=0.98 for a total number of users). Compared to existing methods, the UAV observation tool, covering larger target areas, is suitable for counting park users in a more reliable and efficient way and mapping their use patterns; however, the tool is weaker at collecting detailed user information and surveying under poor weather conditions. Thus, the UAV method could complement existing tools. Finally, this study suggests practical implications of the UAV observation method.

A HUGE thank you to all of you for backing this project, again!