5 files changed, 69 insertions, 3 deletions
diff --git a/cmd/jp/canvas_other.go b/cmd/jp/canvas_other.go
index 053cef7..db0b3d4 100644
--- a/cmd/jp/canvas_other.go
+++ b/cmd/jp/canvas_other.go
@@ -7,4 +7,5 @@ var autoCanvas = map[string]string{
 	plotTypeLine:    canvasTypeQuarter,
 	plotTypeScatter: canvasTypeBraille,
 	plotTypeHist:    canvasTypeQuarter,
+	plotTypeHeatmap: canvasTypeFull,
 }
diff --git a/cmd/jp/canvas_windows.go b/cmd/jp/canvas_windows.go
index de22e5b..56cc212 100644
--- a/cmd/jp/canvas_windows.go
+++ b/cmd/jp/canvas_windows.go
@@ -7,4 +7,5 @@ var autoCanvas = map[string]string{
 	plotTypeLine:    canvasTypeFull,
 	plotTypeScatter: canvasTypeFull,
 	plotTypeHist:    canvasTypeFull,
+	plotTypeHeatmap: canvasTypeFull,
 }
diff --git a/cmd/jp/heatmap.go b/cmd/jp/heatmap.go
new file mode 100644
index 0000000..9ebd2fe
--- /dev/null
+++ b/cmd/jp/heatmap.go
@@ -0,0 +1,55 @@
+package main
+
+import (
+	"log"
+	"reflect"
+
+	"github.com/sgreben/jp/pkg/data"
+	"github.com/sgreben/jp/pkg/draw"
+	"github.com/sgreben/jp/pkg/plot"
+)
+
+func heatmapData(xv []reflect.Value, yv []reflect.Value, nbins uint) (heatmap *data.Heatmap) {
+	var x, y []float64
+	for i := range xv {
+		if xv[i].IsValid() && xv[i].CanInterface() {
+			xvi, ok := xv[i].Interface().(float64)
+			if ok {
+				x = append(x, xvi)
+			}
+		}
+	}
+	for i := range yv {
+		if yv[i].IsValid() && yv[i].CanInterface() {
+			yvi, ok := yv[i].Interface().(float64)
+			if ok {
+				y = append(y, yvi)
+			}
+		}
+	}
+	if len(x) != len(y) {
+		log.Fatal(len(x), " = len(x) != len(y) = ", len(y))
+	}
+	points := make([][2]float64, len(x))
+	for i := 0; i < len(x); i++ {
+		points[i] = [2]float64{x[i], y[i]}
+	}
+	if len(x) == 0 {
+		log.Fatal("no valid x values given")
+	}
+	bins := data.NewBins2D(points)
+	bins.X.Number = int(nbins)
+	bins.Y.Number = int(nbins)
+	if nbins == 0 {
+		bins.X.Number = data.BinsSturges(len(points))
+		bins.Y.Number = data.BinsSturges(len(points))
+	}
+	heatmap = data.NewHeatmap(data.Histogram2D(points, bins))
+	return
+}
+
+func heatmap(xv, yv []reflect.Value, c draw.Canvas, nbins uint) string {
+	heatmap := heatmapData(xv, yv, nbins)
+	chart := plot.NewHeatMap(c.GetBuffer())
+	return chart.Draw(heatmap)
+}
diff --git a/cmd/jp/hist.go b/cmd/jp/hist.go
index 77c04e6..c49f387 100644
--- a/cmd/jp/hist.go
+++ b/cmd/jp/hist.go
@@ -25,7 +25,7 @@ func histogramData(xv []reflect.Value, nbins uint) (groups []string, counts []fl
 	bins := data.NewBins(x)
 	bins.Number = int(nbins)
 	if nbins == 0 {
-		bins.ChooseSturges()
+		bins.Number = data.BinsSturges(len(x))
 	}
 	hist := data.Histogram(x, bins)
 	groups = make([]string, len(hist))
diff --git a/cmd/jp/main.go b/cmd/jp/main.go
index 173ac27..ac5b099 100644
--- a/cmd/jp/main.go
+++ b/cmd/jp/main.go
@@ -31,6 +31,7 @@ const (
 	plotTypeBar     = "bar"
 	plotTypeScatter = "scatter"
 	plotTypeHist    = "hist"
+	plotTypeHeatmap = "hist2d"
 )
 
 const (
@@ -53,6 +54,7 @@ var config = configuration{
 			plotTypeBar,
 			plotTypeScatter,
 			plotTypeHist,
+			plotTypeHeatmap,
 		},
 	},
 	CanvasType: enumVar{
@@ -123,6 +125,11 @@ func init() {
 }
 
 func match(in interface{}, p *jsonpath.JSONPath) [][]reflect.Value {
+	defer func() {
+		if r := recover(); r != nil {
+			log.Println("error evaluating JSONPath", p.String+":", r)
+		}
+	}()
 	out, err := p.FindResults(in)
 	if err != nil {
 		log.Println(err)
@@ -137,13 +144,13 @@ func main() {
 		dec := json.NewDecoder(os.Stdin)
 		err := dec.Decode(&in)
 		if err != nil {
-			log.Println(err)
+			log.Println(inputTypeJSON, "input:", err)
 		}
 	case inputTypeCSV:
 		r := csv.NewReader(os.Stdin)
 		rows, err := r.ReadAll()
 		if err != nil {
-			log.Println(err)
+			log.Println(inputTypeCSV, "input:", err)
 		}
 		in = parseRows(rows)
 	}
@@ -175,5 +182,7 @@ func main() {
 		fmt.Println(barPlot(x, y, c))
 	case plotTypeHist:
 		fmt.Println(histogram(x, c, config.HistBins))
+	case plotTypeHeatmap:
+		fmt.Println(heatmap(x, y, c, config.HistBins))
 	}
 }