# Interpolation problem on the list

I have a List of Latitude, Longitude and Measurement.

a = {{{93, 104}, 290}, {{94, 103}, 292}, {{95, 105}, 291}, {{97, 109},
294}, {{97, 102}, 295}};


And, I want to Interpolate this list and plot them using ContourPlot and CountryData. However, error has occured when I use Interpolation:

Interpolation[a]
Interpolation::udeg: Interpolation on unstructured grids is currently only supported for InterpolationOrder->1 or InterpolationOrder->All. Order will be reduced to 1.
Interpolation::umprec: Interpolation on unstructured grids is currently only supported for machine numbers. The data will be coerced to machine precision.


The list is a just peace of my full list. I don't know how to solve this.

• Oh sorry ContourPlot – user2987529 Nov 20 '13 at 13:24

f = Interpolation[a, InterpolationOrder -> 1];