I attended the monthly Phnom Penh GIS meetup yesterday and there was an interesting discussion on lying with maps, or more accurately, misrepresenting data. With this discussion fresh in my mind I was thumbing through today’s Phnom Penh Post (Cambodia’s largest English language daily newspaper), and saw an article titled Kingdom’s arable land all but gone with a map that caught my eye:
If you don’t have time to read the whole article, I will summarize it for you: A local human rights NGO has created a map showing economic land concessions in Cambodia. Economic land concessions are a contentious issue here in Cambodia and much of the developing world, with many allegations of government “land grabbing”. In other words, forcibly taking farmland from villagers and selling it to private sector companies.
The article and the maps authors claim the data shows that economic land concessions make up 21.99% of Cambodia’s available land. Whilst Cambodia’s total arable land makes up 20.44%. Both of these numbers appear in line with currently available data.
The map contains a polygon layer to show the land concessions and the mining concessions, and ‘Parks, Forests & Sanctuaries’. But more interesting than what layers they included were the layers they decided not to include in the map, namely the polygon that showed the location of arable land, which is clearly a key part of this map and the conclusions that were made from it.
There are two problems with this. Firstly the term ‘arable’ is ambiguous. Technically it’s land that could be used for farming but isn’t or isn’t all year round, but in everyday language the term arable land and agricultural land are used interchangeably. For example: WikiAnswers: What is arable land?, or Yahoo Answers: What’s the difference between arable and agricultural land?
More interestingly in the context of Cambodia, rice paddy is classed as arable land:
A paddy field is a flooded parcel of arable land used for growing rice and other semi-aquatic crops.
So as you can see, with a term as ambiguous as this it’s absolutely necessarily to include the arable data in your map so the user can clearly see what the publisher classes as arable land especially in the presence of shock headlines such as “Kingdom’s arable land all but gone”.
So here’s a map that I made using Mango that clearly shows the economic land concessions and mining concessions but also includes the land use data. I’ll leave you to draw your own conclusions:
Map Link: Mango – Impact of Land & Mining Concessions on Cambodias Arable Land
Also thanks to Open Development Cambodia for sharing the data online!
Apparently a later version of the map and official commentary from Licadho will appear in a future issue of the Cambodia Daily. It seems like this may have been a case of the Phnom Penh Post jumping the gun rather than Licadho producing an incomplete/misleading map. As soon as new data is available we’ll update our map.