Frequently Asked Questions

Question:

If I am playing this game to verify whether a photo is Cropland or not, why does the game tell me if I'm correct or incorrect? If it already knows what Cropland is, what is the point of the game?

Answer:

The game is built around learning the answers to whether cropland exists or not by providing the same rectangles to multiple players. The first few times that the rectangle is given to a player, we simply assume the answer is correct. Then over time we build a profile of answers for each rectangle and we use a majority rule to determine if subsequent answers are correct or not. Eventually when we have enough information about each rectangle, we remove it from the game. As the game progresses, players are given new territories so this sequence repeats itself as more areas are classified.

Question:

Will the data from the game become available?

Answer:

Yes, we will make the data openly available after the game is finished, after we have had some time to do quality assurance, and after we have used the data for improving our global hybrid cropland map. We will provide more details about data access in the future through our monthly Geo-Wiki newsletter.

Question:

How will the data be used in subsequent scientific research?

Answer:

We will use the data in a number of different ways. Some of the data will be used to create (or calibrate) the global cropland map, building upon a hybrid methodology that we have used in the past. Some of the data will be used for validation (as an independent sample) to check the accuracy of the global cropland map. We will also mine the dataset to look for patterns regarding quality, e.g. how many samples do you need to provide to the 'crowd' before you can be confident in the answers? Are there regional patterns that emerge from the data? Etc. These types of very interesting questions will help improve the science behind the use of crowdsourced data for scientific research. We are eventually planning to map the whole world this way.

Question:

What exactly is cropland? Sometimes I see orchards and I'm not sure if this is cropland or not.

Answer:

We use the FAO definition for cropland, which is both annual crops (e.g. maize, wheat) and perennial crops (such as coffee, tea, palm oil, fruit orchards, etc.). Forest plantations and pasture, on the other hand, are not considered croplands. Forest plantations are for timber harvesting and pasture is for livestock so they are not part of the definition of cropland.

To help you we posted some more images of cropland in the examples ‘what is cropland’ and added some examples of pasture under ‘what is non-cropland’ in the gallery.