I am trying to refine a raster dataset of annual rainfall from a 5km grid down to a 100m grid. Before I continue, I am aware that this could result in some uncertainty regarding the data. However, the data is only available in the 5km grids, and this is of no use to me, as I am looking to compare rainfall to landuse, and the landuse map is to a 100m grid.
To get around this, I thought I would be able to infill the data through the use of contours (as rainfall data is generally gradient based, rather than discrete isolated data points)
I contoured the 5km raster file using Contour(Spatial Analyst), and then tried to use the contour file to create a new raster file (Feature to Raster) at a 100m resolution. However, because the contour feature is a polyline feature, there isn't any data between the contours. This means that anywhere the contour lines fall more than 100m apart, the raster file leaves a blank pixel.
As I see it, there are three options that I may be able to look into (no idea how, or if, the first two would work)
Option 1: Directly refining the resolution of the original raster file, by increasing the resolution from 5km to 100m pixels and infilling the new pixels with values interpolated from the original file.
Option 2: Some sort of interpolation tool, (I saw several in the Geostats toolbox, but don't understand how they work) that could transform the contour polyline feature into a continuous dataset, which could then be converted to raster.
Option 3: Create a contour file with ridiculously fine contours (I have already tried 0.5 mm, over a range from ~ 500mm to 3000mm, and this didn't do the trick in places)
Any help would be appreciated.