A sky-high government-funded project is under way to map and analyse each and every one of the thousands of rooftops here.
The aim? To figure out on average how much each is exposed to the sun.
This information will be shared with Singaporeans in the hope that more will warm towards installing solar panels, as the nation ramps up its use of the sun's energy.
This work by the Solar Energy Research Institute of Singapore (Seris) is part of an ambitious, wider effort by the Singapore Land Authority (SLA) to photograph and map, in 3D, the entire country's landscape.
Since April 10, light planes have been criss-crossing the island at an altitude of up to 1,200m, taking aerial shots and doing laser scans. The effort will take about 40 days.
The project is expected to be completed by 2016.
An SLA spokesman said that the mapping would "improve decision-making" as users such as government agencies can then visualise, analyse and understand the landscape better.
For example, national water agency PUB will be using the map to better manage storm water. The Civil Aviation Authority of Singapore will harness it to design more efficient flight paths.
The first of the project's two phases will cost about $3.3 million. When complete, the 3D map will be adapted for public use.
As for Seris, which is funded by the National Research Foundation, the Economic Development Board and the National University of Singapore, it aims to make its version of the map publicly available online within a year.
The Frankfurt University of Applied Sciences, which mapped the German city last year, has a similar map on its website.
Every rooftop on the Singapore map will be coloured red, orange or yellow, depending on how suited it is to harnessing solar energy.
Seris will rate this by using models to assess the slant of each roof, and simulate shadows formed as the sun rises and sets. For example, a higher building may shade a nearby one, giving it less sun, while flat roofs are more suitable for solar panels.
Far from being just a technical exercise, the aim here is education, said Seris deputy chief executive Thomas Reindl.
A bungalow owner, condominium developer or factory owner who clicks on their rooftop would learn how much solar panel capacity they could fit on it, what this might cost, and how quickly they could recoup their investment.
It is about informing people, he said. "Solar energy has not fully taken off because people don't know too much about it yet... it has come down in price."
In October 2012, The Straits Times reported that the cost of installing and maintaining solar panels had become on a par here, for the first time, with that of using conventional electricity. Conventional electricity tariffs are 25.73 cents per kilowatt hour.
Seris is also revamping its National Solar Repository website to better educate people. Giving the public "full understanding" of solar energy's potential would help them harvest it, added Dr Reindl.
But he stressed the need to manage the impact of connecting more solar power to the national grid, an issue the Government is aware of. Solar energy generation can vary, depending on factors such as weather.
Seris will work with the Energy Market Authority to simulate the impact, using the 3D map.
Solar panels installed here as of June last year can generate at most about 12MW, six times that of 2009's figure, but a tiny fraction of the country's electricity demand.