# Holoviews/Datashaded map overlay not displaying

## Solution 1:

According to the holoviews docs, `hv.rasterize`

is a high-level resampling interface and passes parameters to several internal methods:

:`holoviews.core.operation.Operation`

`group, input_ranges`

:`holoviews.operation.datashader.LinkableOperation`

`link_inputs`

:`holoviews.operation.datashader.ResamplingOperation`

`dynamic, streams, expand, height, width, x_range, y_range, x_sampling, y_sampling, target, element_type, precompute`

:`holoviews.operation.datashader.AggregationOperation`

`vdim_prefix`

Based on this, it looks like your arguments x_sampling and y_sampling are passed to `ResamplingOperation`

, which are described:

`x_sampling = param.Number(allow_None=True, inclusive_bounds=(True, True), label=’X sampling’)`

Specifies the smallest allowed sampling interval along the x axis.

`y_sampling = param.Number(allow_None=True, inclusive_bounds=(True, True), label=’Y sampling’)`

Specifies the smallest allowed sampling interval along the y axis.

So, I'd guess that the issue is that providing the arguments `x_sampling=1, y_sampling=1`

to `rasterize`

has the effect of aggregating all of your data to 1 degree, or approximately 110 km/70 mile blocks, which is causing the blockiness in your figure. Changing these parameters to a smaller value, such as 0.1 or smaller, should resolve the issue, as long as your data itself has sufficient resolution.