--- a/pkg/geoserver/templates.go	Thu Jul 04 11:03:36 2019 +0200
+++ b/pkg/geoserver/templates.go	Thu Jul 04 11:26:11 2019 +0200
@@ -30,21 +30,65 @@
 const (
 	selectClassBreaksSQL = `
 SELECT config_val FROM sys_admin.system_config
-WHERE config_key = 'morphology_classbreaks'`
+WHERE config_key = $1`
 )
 
 func init() {
 	RegisterStylePreprocessor(
 		"sounding_results_contour_lines_geoserver",
-		templateSRContourLines)
+		templateContourLinesFunc("morphology_classbreaks"))
+	RegisterStylePreprocessor(
+		"sounding_differences",
+		templateContourLinesFunc("morphology_classbreaks_compare"))
 }
 
-type colorClass struct {
-	value float64
-	color color.RGBA
+type (
+	colorClass struct {
+		value float64
+		color color.RGBA
+	}
+
+	colorClasses []colorClass
+
+	classBreak struct {
+		High    float64
+		HasHigh bool
+		Low     float64
+		HasLow  bool
+		color   color.RGBA
+	}
+)
+
+func (cb *classBreak) Color() string {
+	return fmt.Sprintf("#%02x%02x%02x",
+		cb.color.R,
+		cb.color.G,
+		cb.color.B,
+	)
 }
 
-type colorClasses []colorClass
+func (cc colorClasses) toClassBreaks() []classBreak {
+
+	cbs := make([]classBreak, len(cc), len(cc)+1)
+	for i := range cc {
+		if i > 0 {
+			cbs[i].Low = cc[i-1].value
+			cbs[i].HasLow = true
+		}
+		cbs[i].High = cc[i].value
+		cbs[i].HasHigh = true
+		cbs[i].color = cc[i].color
+	}
+	if len(cc) > 0 {
+		cbs = append(cbs, classBreak{
+			color:  cc[len(cc)-1].color,
+			Low:    cc[len(cc)-1].value,
+			HasLow: true,
+		})
+	}
+
+	return cbs
+}
 
 func (cc colorClasses) interpolate(v float64) (color.RGBA, bool) {
 	if len(cc) == 0 || v < cc[0].value || v > cc[len(cc)-1].value {
@@ -183,7 +227,13 @@
 	return final, err
 }
 
-func templateSRContourLines(data string) (string, error) {
+func templateContourLinesFunc(configKey string) func(string) (string, error) {
+	return func(data string) (string, error) {
+		return templateContourLines(data, configKey)
+	}
+}
+
+func templateContourLines(data, configKey string) (string, error) {
 	tmpl, err := template.New("template").Parse(data)
 	if err != nil {
 		return "", err
@@ -191,7 +241,7 @@
 
 	var cb []classBreak
 
-	if cb, err = getSRContoursClassBreaks(); err != nil {
+	if cb, err = countourLinesClassBreaks(configKey); err != nil {
 		return "", err
 	}
 
@@ -202,46 +252,7 @@
 	return buf.String(), nil
 }
 
-type classBreak struct {
-	High    float64
-	HasHigh bool
-	Low     float64
-	HasLow  bool
-	color   color.RGBA
-}
-
-func (cb *classBreak) Color() string {
-	return fmt.Sprintf("#%02x%02x%02x",
-		cb.color.R,
-		cb.color.G,
-		cb.color.B,
-	)
-}
-
-func (cc colorClasses) toClassBreaks() []classBreak {
-
-	cbs := make([]classBreak, len(cc), len(cc)+1)
-	for i := range cc {
-		if i > 0 {
-			cbs[i].Low = cc[i-1].value
-			cbs[i].HasLow = true
-		}
-		cbs[i].High = cc[i].value
-		cbs[i].HasHigh = true
-		cbs[i].color = cc[i].color
-	}
-	if len(cc) > 0 {
-		cbs = append(cbs, classBreak{
-			color:  cc[len(cc)-1].color,
-			Low:    cc[len(cc)-1].value,
-			HasLow: true,
-		})
-	}
-
-	return cbs
-}
-
-func getSRContoursClassBreaks() ([]classBreak, error) {
+func countourLinesClassBreaks(configKey string) ([]classBreak, error) {
 
 	var config string
 	ctx := context.Background()
@@ -249,7 +260,11 @@
 		ctx,
 		"sys_admin",
 		func(conn *sql.Conn) error {
-			return conn.QueryRowContext(ctx, selectClassBreaksSQL).Scan(&config)
+			return conn.QueryRowContext(
+				ctx,
+				selectClassBreaksSQL,
+				configKey,
+			).Scan(&config)
 		},
 	); err != nil {
 		return nil, err