Provide a ChartContext method to downsample the representation of the source data to a custom bucket size (not sure if something like this exists already, but could not find it).
Sometimes we are dealing with data sampled very frequently over long periods of time, which can make our chart look too cluttered.
To fix this in one of my projects, I wrote the following function for DateTime data (x axis).
fn downsample(
data: &[(DateTime<Utc>, f64)],
bucket_size: Duration,
) -> Vec<(DateTime<Utc>, f64)> {
if data.is_empty() {
return vec![];
}
let mut buckets: Vec<(DateTime<Utc>, f64)> = Vec::new();
let mut bucket_start = data[0].0;
let mut sum = 0.0;
let mut count = 0u32;
for &(dt, val) in data {
if dt >= bucket_start + bucket_size {
if count > 0 {
let mid = bucket_start + bucket_size / 2;
buckets.push((mid, sum / count as f64));
}
bucket_start = dt;
sum = 0.0;
count = 0;
}
sum += val;
count += 1;
}
// Last bucket
if count > 0 {
let mid = bucket_start + bucket_size / 2;
buckets.push((mid, sum / count as f64));
}
buckets
}Then you just pass the new bucket size, how often you want a sample to be displayed.
let data = downsample(&data, Duration::hours(12));
chart
.draw_series(LineSeries::new(data, color.stroke_width(2)))?
.label(position.to_string())
.legend(move |(x, y)| {
PathElement::new(vec![(x, y), (x + 20, y)], color.stroke_width(2))
});Final result:
Provide a
ChartContextmethod to downsample the representation of the source data to a custom bucket size (not sure if something like this exists already, but could not find it).Sometimes we are dealing with data sampled very frequently over long periods of time, which can make our chart look too cluttered.
To fix this in one of my projects, I wrote the following function for
DateTimedata (x axis).Then you just pass the new bucket size, how often you want a sample to be displayed.
Final result: