The challenge of climate crisis is a topic that has been present in our lives as never before. To do our own contribution, we decided to make an app that informs the user about emissions, displays options according to the individual preferences of a user, and helps him make more climate-friendly decisions.

What it does

When planning how to get to your destination, Greentastic tells you about how fast, expensive, and climate friendly each mean of transportation is (with respect to carbon emissions and nitrogen oxide pollution), as well as how many calories you will burn on your trip. Based on the users preferences, it will order the different options by a weighted average of the criteria. In detail, the app initially shows the map and one can type in a destination. Then Greentastics computes a score for each criteria (e.g. price) and shows the absolute value and the colour-coded score. When selecting an option, the corresponding route is drawn on Apple Maps. On a second screen that can be accessed in the bottom bar, the user can set his criteria-weighting and the type of car he would use. On a third screen, stats about monthly carbon emissions etc can be computed in later versions of the app.

How we built it

The app uses a Python backend that uses the information of the Google Maps API for a given route. The function at the center of the program uses stats taken from scientific literature to compute a value for each of the criteria "travel duration", "cost", "CO2 emission", "toxicity", and "calories burned". These are normalized and summed to yield a weighted average. The weights are set according to the preferences of the user. The frontend is programmed with Swift in Xcode.

Challenges we ran into

Firstly, it was harder than expected finding reliable average values for prices, emissions and toxicity. Often the numbers varied widely. Secondly, it took a while to set up Google Cloud Services and manage to employ the app there.

Accomplishments that we're proud of

The app is fully functional already and you can even use it on your iPhone (download via iOS Testflight). We developed a python-based backend that queries the Google Maps API and is currently deployed on Google Cloud. Overall, we are very proud to have made an app that both looks good and works elegantly, while being useful both for the user directly, as well as society as a whole.

What we learned

During the initial phase of the project, we learnt a lot about how to plan our steps properly and distribute tasks to work with highest efficiency. Furthermore, since our skills vary a lot, we could learn a lot from each other when merging our parts and discussing the code from time to time.

What's next for Greentastic

There is some more minor information that can make the scores more realistic and more precise, such as accounting for elevation for example. On top of that, we have plans on adding daily, weekly, and monthly summary statistics. We also want to add gamification elements such as badges, levels, challenges and so on.

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