Tower defense games like Forest Defenders are a sub-genre of real-time strategy video games. The goal of tower defense games is to try to stop enemies from crossing a map by building traps to slow them down and towers which shoot at them as they pass. Enemies and towers usually have varied abilities, costs, and upgrade prices. When an enemy is defeated, the player earns money or points, which are used to buy or upgrade towers. Choosing the type and positioning of the personal towers is the essential strategy of the game.
A phase of the game is dedicated specifically to the purpose of gathering detections of deforestation from the players. The game is played in two steps. First is the detection phase, during which the player looks for deforested areas by comparing satellite images of the same area taken at different dates. What the player identifies as deforestation is then stored into a server for further analysis.
The game then randomly selects some of the areas where the player indicated possible deforestation and gives the player a plus or minus depending on if the player’s detections match Terra-i ones. Next the tower defense phase starts and continues until the player either survives all the enemy’s attacks or loses the game.
This first prototype of Forest Defenders is based on MODIS NDVI images with a resolution of 250m. Although it is working smoothly and is fully playable, users have been struggling to interpret the NDVI maps. The next step of development will therefore be to incorporate new satellite imagery datasets such as Landsat 8 as a basemap.
Grégoire Aubert, main developer of this first prototype of Forest Defenders, says “The actual version of Forest Defenders, even without a perfect balancing of its elements and its difficulty, seems to appeal to people. Most of the people who tried it out, liked it. They found it a bit difficult at first and didn’t always understood how to recognize and detect a deforestation. But after few attempts, they wanted to play again and try to beat it.” He continued, “this project was challenging and required a lot of work to achieve the actual result. I acquired a lot of experience in game and mobile application development. And learning all these new things and developing this project was very exciting and interesting.”
You can download an alpha version of the game here http://ape.iict.ch/research/forestdefenders/ForestDefenders.apk and install it by following these instructions.
NOTE: This is only a prototype version which does not represent in any case the final game. This apk has been tested on many devices and has been proven to be stable and safe. However, you install this app at your own risk and we decline any responsibility for the safety of your device if you do so.
Blog post by Louis Reymondin. Revision of English-language version by Caitlin Peterson (CIAT / CCAFS visiting researcher).