histogram returns bad data when setting start and end parameters

When calling the histogram URL for a numeric column with start and end parameters, the endpoint returns bad data for the buckets in the extremes.

NO START

{
	"bin_width": 46.6666666666667,
	"bins_count": 3,
	"bins_start": 9,
	"bins": [{
		"bin": 0,
		"min": 9,
		"max": 55,
		"avg": 35.405126849894295,
		"freq": 3784
	}, {
		"bin": 1,
		"min": 56,
		"max": 102,
		"avg": 75.28977482465855,
		"freq": 2709
	}, {
		"bin": 2,
		"min": 103,
		"max": 149,
		"avg": 123.25338491295938,
		"freq": 517
	}],
	"type": "histogram"
}

We can see that this histogram has a range from 9 to 149.

If we set start: 50 and end: 100 we get

{
	"bin_width": 16.6666666666667,
	"bins_count": 3,
	"bins_start": 50,
	"bins": [{
		"bin": 0,
		"min": 9,
		"max": 66,
		"avg": 40.28936078936079,
		"freq": 4662
	}, {
		"bin": 1,
		"min": 67,
		"max": 83,
		"avg": 74.27996254681648,
		"freq": 1068
	}, {
		"bin": 2,
		"min": 84,
		"max": 149,
		"avg": 105.07421875,
		"freq": 1280
	}],
	"type": "histogram"
}

We can see that the buckets are 3, starting at 50 with a width of 16.67. So they are

|------|------|------|
50   66.7   83.4    100

This is correct. We asked for data between 50 and 100 so these are the proper buckets.

BUT if we study the bins data we get: Bin 0: min 9, max 66 (min should be above 50) Bin 1: min 67, max 83 (this is ok) Bin 2: min 84, max 149 (max should be below 100)

[ivanmalagon]

We’re already sending them to the endpoint only if both are defined so we’ll state it in the CARTO.js documentation and add the proper validations to make sure that both are defined.

[Algunenano]

E.g: as per the code, the max and min are calculated when you pass start >= end.

That specific case is handled in the base view so they will be flipped before getting there, but it’s true that unexpected things will happen if you only pass one of them.