Hi there, I just thought I'd learn Swift Charts and I'm having an issue where the y axis scale is displaying numbers well into the hundreds while the chart annotation and sample data proves that there aren't that many. See attached images: https://drive.google.com/file/d/1nSw5MEXmbY0O4CQ3DRNy_BUVS2paTUCf/view?usp=sharing https://drive.google.com/file/d/16ttrpsXov0od7JhCbO5mU8VTsTG_ElHb/view?usp=sharing Code is below ↓ Thanks, Josh

import SwiftUI
import Charts

struct EntryObservation {
    var subject: Subject
    var sectionGroup: SectionGroup
    var time: Date
}

struct Subject {
    var name: String
    var color: Color
}

struct SectionGroup {
    var name: String
}

struct ClickerView: View {
    var entryObservations: [EntryObservation]
    @State private var categorization = 1
    var body: some View {
        Chart (entryObservations, id: \.time) {entryObservation in
            Plot {
            switch categorization {
            case 2:
                BarMark(x: .value("Section", entryObservation.sectionGroup.name), y: .value("Count", entryObservations.filter { $0.sectionGroup.name == entryObservation.sectionGroup.name }.count))
                    .foregroundStyle(entryObservation.subject.color)
                    .cornerRadius(10)
                    .annotation(position: .top) {
                        Text("\(entryObservations.filter { $0.sectionGroup.name == entryObservation.sectionGroup.name }.count)")
                            .foregroundColor(Color.gray)
                            .font(.system(size: 12, weight: .bold))
                    }
            case 3:
                let count = entryObservations.filter {
                                let timeInterval = entryObservation.time.timeIntervalSince($0.time)
                                return timeInterval >= 0 && timeInterval < 400
                            }.count
                BarMark(x: .value("Time", entryObservation.time ..< entryObservation.time.advanced(by: 400)), y: .value("Count", count))
                    .cornerRadius(5)
                    .foregroundStyle(entryObservation.subject.color)
            default:
                BarMark(x: .value("Subject", entryObservation.subject.name), y: .value("Count", entryObservations.filter { $0.subject.name == entryObservation.subject.name }.count))
                    .cornerRadius(10)
                    .foregroundStyle(entryObservation.subject.color)
                    .annotation(position: .top) {
                        Text("\(entryObservations.filter { $0.subject.name == entryObservation.subject.name }.count)")
                            .foregroundColor(Color.gray)
                            .font(.system(size: 12, weight: .bold))
                    }
            }
        }
        }.padding()
            .chartYAxisLabel("Count")
            .chartLegend(categorization == 2 ? .visible : .hidden)
            .chartLegend(position: .top)
            .safeAreaInset(edge: .top) {
                VStack {
                    Picker("Categorisation", selection: $categorization) {
                        Text("Subject").tag(1)
                        Text("Section").tag(2)
                        Text("Time Interval").tag(3)
                    }
                    .pickerStyle(.segmented)
                }
            }
    }
}

let entryObservations: [EntryObservation] = [
    EntryObservation(subject: Subject(name: "Men", color: .blue), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 1000)),
    EntryObservation(subject: Subject(name: "Men", color: .blue), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 1300)),
    EntryObservation(subject: Subject(name: "Men", color: .blue), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 2000)),
    EntryObservation(subject: Subject(name: "Boys", color: .red), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 1900)),
    EntryObservation(subject: Subject(name: "Boys", color: .red), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 2200)),
    EntryObservation(subject: Subject(name: "Boys", color: .red), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 2500)),
    EntryObservation(subject: Subject(name: "Girls", color: .teal), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 2800)),
    EntryObservation(subject: Subject(name: "Girls", color: .teal), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 3100)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 3400)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 3700)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 4000)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 4300)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 4600)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "Mall"), time: Date(timeIntervalSince1970: 4900)),
    EntryObservation(subject: Subject(name: "Women", color: .mint), sectionGroup: SectionGroup(name: "School"), time: Date(timeIntervalSince1970: 5200))

]

#Preview {
    ClickerView(entryObservations: entryObservations)
}

The solution, thanks to Chris Parker was to set the y axis to y: .value("Count", 1).

For a full explanation see: [codecrew.codewithchris.com/t/swiftui-charts-y-axis-scale-not-reflecting-data/25235/2?u=the-wolf]