Assigning a 3d polygon based on value in Mapbox Studio - mapbox

Question

I am pretty new to GIS as a whole. I have a simple flat file in a csv format, as an example:
name, detail, long, lat, value
a, 123, 103, 22, 5000
b, 356, 103, 45, 6000
What I am trying to achieve is to assign a 3d polygon in Mapbox such as in this example. While the settings might be quite straight forward in Mapbox where you assign a height and color value based on a data range, it obviously does not work in my case.
I think I am missing out other files such as mentioned in the blog post, like shapefiles or some other file that is required to assign 3d layouts to the 3d extrusion.
I need to know what I am missing out in configuring a 3d polygon, say a cube in Mapbox based on the val data column in my csv.

Answer 1

So I figured what I was missing was the coordinates that make up the polygons I want to display. This can easily be defined in a geojson file format, if you are interested in the standards, refer here. For the visual I need, I would require:
Points (typically your long and lat coordinates)
Polygon (a square would require 5 vertices, the lines connecting and
defining your polygon)
Features (your data points)
FeatureCollection (a collection of features)
This are all parts of the geojson format, I used Python and its geojson module which comes with everything I need to do the job.
Using a helper function below, I am able to compute square/rectangular boundaries based on a single point. The height and width defines how big the square/rectangle appears.
def create_rec(pnt, width = 0.00005, height = 0.00005):
pt1 = (pnt[0] - width, pnt[1] - height)
pt2 = (pnt[0] - width, pnt[1] + height)
pt3 = (pnt[0] + width, pnt[1] + height)
pt4 = (pnt[0] + width, pnt[1] - height)
pt5 = (pnt[0] - width, pnt[1] - height)
return Polygon([[pt1,pt2,pt3,pt4,pt5]]) #assign to a Polygon class from geojson
From there it is pretty straight forward to append them into list of features, FeatureCollection and output as a geojson file:
with open('path/coordinates.csv', 'r') as f:
headers = next(f)
reader = csv.reader(f)
data = list(reader)
transform = []
for i in data:
#3rd last value is x and 2nd last is the y
point = Point([float(i[-3]), float(i[-2])])
polygon = create_rec(point['coordinates'])
#in my case I used a collection to store both points and polygons
col = GeometryCollection([point, polygon])
properties = {'Name':i[0]}
feature = Feature(geometry = col, properties = properties)
transform.append(feature)
fc = FeatureCollection(transform)
with open('target_doc_u.geojson', 'w') as f:
dump(fc, f)
The output file target_doc_u would contain all the listed items above that allows me to plot my point, as well as continue of the blog post in Mapbox to assign my filled extrusion