I'm trying to create a "heatmap" style visualization from a number of geopoints and values associated with them. I have been following along with this blog post.
I've got a CSV file of points like the following:
POINT_Y,POINT_X,Value -41.157785,174.8343481,5 -41.1575385,174.8347111,4 -41.1574106,174.8347659,9 -41.1572644,174.8348964,2 -41.1570742,174.8351378,7 -41.1569067,174.835225,1
I've converted them into a GeoTIFF file with interpolation using gdal_grid. This was the command I ran:
gdal_grid -a invdist:power=3.0:smoothing=1.0:radius1=90000:radius2=90000:max_points=0 -a_srs WGS84 -of GTiff -ot Float64 -l test test.vrt test.tiff
That seems to work and generates a GeoTIFF file that looks right (I can paste the gdalinfo output, in case that helps)
I'm wondering how I style the points to get something similar to what is shown at the bottom of that blog post? I'm using TileMill to style my maps, and when I add the GeoTIFF to my project as a layer I get a white box that's in the correct place:
But of course I can't see any of the individual points on the grid. I'm fairly sure I'm missing an important step to colourize the points, I'm just not sure what it is!
I don't have any Carto styles applied to the layer in TileMill.
Thanks in advance!