diff --git a/uppsrc/ScatterDraw/DataSource.cpp b/uppsrc/ScatterDraw/DataSource.cpp
index b1983a739..1fcbef9f9 100644
--- a/uppsrc/ScatterDraw/DataSource.cpp
+++ b/uppsrc/ScatterDraw/DataSource.cpp
@@ -51,6 +51,19 @@ double DataSource::Avg(Getdatafun getdata) {
 	return ret/count;
 }
 
+double DataSource::IsSorted(Getdatafun getdata) {
+	int64 num = GetCount();
+	if (num == 0)
+		return false;
+	if (num == 1)
+		return 1;
+	for (int i = 1; i < num; ++i) {
+		if (Membercall(getdata)(i) < Membercall(getdata)(i - 1))
+			return false;
+	}
+	return true;
+}
+
 double DataSource::Variance(Getdatafun getdata, double avg) {
 	if (IsNull(avg))
 		avg = Avg(getdata);
@@ -111,17 +124,23 @@ Vector<int64> DataSource::Envelope(Getdatafun getdataY, Getdatafun getdataX, dou
 		}
 		if (IsNull(numComparisons))
 			continue;
-		if (numComparisons > 2)
-			ret << i;
+		if (numComparisons > 2) {
+			if (!ret.IsEmpty()) {
+				int64 prev_i = ret[ret.GetCount() - 1];
+				if (Membercall(getdataX)(prev_i) != x)
+					ret << i;
+			} else 
+				ret << i;
+		}
 	}
 	return ret;
 }
 
-bool GreaterThan(double a, double b) {return a > b;}
-bool LowerThan(double a, double b) {return a < b;}
+bool GreaterEqualThan(double a, double b) {return a >= b;}
+bool LowerEqualThan(double a, double b) {return a <= b;}
 
-Vector<int64> DataSource::UpperEnvelope(Getdatafun getdataY, Getdatafun getdataX, double width) {return Envelope(getdataY, getdataX, width, GreaterThan);}
-Vector<int64> DataSource::LowerEnvelope(Getdatafun getdataY, Getdatafun getdataX, double width) {return Envelope(getdataY, getdataX, width, LowerThan);}
+Vector<int64> DataSource::UpperEnvelope(Getdatafun getdataY, Getdatafun getdataX, double width) {return Envelope(getdataY, getdataX, width, GreaterEqualThan);}
+Vector<int64> DataSource::LowerEnvelope(Getdatafun getdataY, Getdatafun getdataX, double width) {return Envelope(getdataY, getdataX, width, LowerEqualThan);}
 
 Vector<Pointf> DataSource::MovingAverage(Getdatafun getdataY, Getdatafun getdataX, double width) {
 	Vector<Pointf> ret;
@@ -204,6 +223,8 @@ bool DataSource::SinEstim_FreqPhase(double &frequency, double &phase, double avg
 			lastZero = zero;
 		}
 	}
+	if (T == 0 || numT == 0)
+		return false;
 	T = 2*T/numT;
 	frequency = 2*M_PI/T;			
 	phase = -frequency*firstZero;
@@ -253,100 +274,4 @@ Vector<Pointf> DataSource::FFT(Getdatafun getdata, double tSample) {
 }
 
 
-bool Spline::Load(Vector<double>& xdata, Vector<double>& ydata)
-{
-    if(!IsInputSane(xdata, ydata))
-        return false;
-
-    int n = xdata.GetCount() - 1;
-    
-    Vector<double> h;
-    for(int i = 0; i < n; ++i)
-        h << (xdata[i+1] - xdata[i]);
-
-    Vector<double> alpha;
-    for(int i = 0; i < n; ++i)
-        alpha << (3.*(ydata[i+1] - ydata[i])/h[i] - 3*(ydata[i]-ydata[i-1])/h[i-1]);
-
-    Vector<double> l, mu, z;
-    l.SetCount(n+1);
-    mu.SetCount(n+1);
-    z.SetCount(n+1);
-    l[0] = 1;
-    mu[0] = 0;
-    z[0] = 0;
-
-    for(int i = 1; i < n; ++i) {
-        l[i] = 2.*(xdata[i+1] - xdata[i-1]) - h[i-1]*mu[i-1];
-        mu[i] = h[i]/l[i];
-        z[i] = (alpha[i] - h[i-1]*z[i-1])/l[i];
-    }
-
-    l[n] = 1.;
-    z[n] = 0;
-    
-    Vector<double> c;
-    c.SetCount(n+1);
-    c[n] = 0;
-
-	Vector<double> b, d;
-	b.SetCount(n);
-	d.SetCount(n);
-    for(int j = n-1; j >= 0; --j) {
-        c[j] = z[j] - mu[j] * c[j+1];
-        b[j] = (ydata[j+1] - ydata[j])/h[j] - h[j]*(c[j+1] + 2*c[j])/3.;
-        d[j] = (c[j+1] - c[j])/3./h[j];
-    }
-
-    coeff.SetCount(n);
-    for(int i = 0; i < n; ++i) {
-        coeff[i].a = ydata[i];
-        coeff[i].b = b[i];
-        coeff[i].c = c[i];
-        coeff[i].d = d[i];
-        coeff[i].x = xdata[i];
-    }
-    return true;
-}
-
-double Spline::GetY(double x)
-{
-    int j;
-    for (j = 0; j < coeff.size(); j++) {
-        if(coeff[j].x > x) {
-            if(j == 0)
-                j++;
-            break;
-        }
-    }
-    j--;
-
-    double dx = x - coeff[j].x;
-    return coeff[j].a + coeff[j].b*dx + coeff[j].c*dx*dx + coeff[j].d*dx*dx*dx;
-}
-
-bool Spline::IsInputSane(Vector<double>& xdata, Vector<double>& ydata)
-{
-    if(xdata.IsEmpty() || ydata.IsEmpty())
-        return false;
-    
-    if(!IsSorted(xdata))
-        return false;
-
-    bool first = true;
-    double xold;
-    for(int i = 0; i < xdata.GetCount(); ++i) {
-        double x = xdata[i];
-        if(first) 
-            xold = x;
-        else {
-	        first = false;
-	        if( fabs(x - xold) < 1) 
-	            return false;
-	        xold = x;
-        }
-    }
-    return true;
-}
-
 END_UPP_NAMESPACE
\ No newline at end of file
diff --git a/uppsrc/ScatterDraw/DataSource.h b/uppsrc/ScatterDraw/DataSource.h
index 038081c96..aeaf4f3a2 100644
--- a/uppsrc/ScatterDraw/DataSource.h
+++ b/uppsrc/ScatterDraw/DataSource.h
@@ -3,19 +3,6 @@
 
 NAMESPACE_UPP
 
-template <class T>
-bool IsSorted(T& data) {
-	int num = data.GetCount();
-	if (num == 0)
-		return false;
-	if (num == 1)
-		return 1;
-	for (int i = 1; i < num; ++i) {
-		if (data[i] < data[i - 1])
-			return false;
-	}
-	return true;
-}
 
 class DataSource {
 public:
@@ -33,6 +20,7 @@ public:
 	virtual double f(double x)				{NEVER();	return Null;}
 	virtual double f(Vector<double> zn)		{NEVER();	return Null;}
 	virtual int64 GetCount()			{NEVER();	return Null;}
+	bool IsEmpty()						{return GetCount() == 0;}
 	virtual int GetznxCount(int64 id)	{return 0;}
 	virtual int GetznyCount(int64 id)	{return 0;}
 	virtual int GetznFixedCount()		{return 0;}
@@ -50,6 +38,9 @@ public:
 	virtual double MaxX(int64& id) 		{return Max(&DataSource::x, id);}	
 	virtual double MaxX() 				{int64 dummy;	return Max(&DataSource::x, dummy);}	
 	
+	virtual double IsSortedY() 			{return IsSorted(&DataSource::y);}		
+	virtual double IsSortedX() 			{return IsSorted(&DataSource::x);}	
+	
 	virtual double AvgY() 				{return Avg(&DataSource::y);}		
 	virtual double AvgX() 				{return Avg(&DataSource::x);}		
 	virtual double StdDevY(double avg = Null) 	{return StdDev(&DataSource::y, avg);}	
@@ -63,6 +54,7 @@ public:
 	double Min(Getdatafun getdata, int64& id);
 	double Max(Getdatafun getdata, int64& id);
 	double Avg(Getdatafun getdata);
+	double IsSorted(Getdatafun getdata);
 	double StdDev(Getdatafun getdata, double avg = Null);
 	double Variance(Getdatafun getdata, double avg = Null);
 	Vector<int64> UpperEnvelope(Getdatafun getdataY, Getdatafun getdataX, double width);
@@ -402,18 +394,11 @@ public:
 	virtual inline int64 GetCount()	{return numPoints;}
 };	
 
-class Spline {
-public:
-    bool Load(Vector<double>& xdata, Vector<double>& ydata);
-    double GetY(double x);
-
-private:
-    struct Coeff{double a, b, c, d, x;};
-    Vector<Coeff> coeff;
-    
-    bool IsInputSane(Vector<double>& xdata, Vector<double>& ydata);
+struct PointfLess {
+	bool operator () (const Pointf& a, const Pointf& b) const { return a.x < b.x; }
 };
 
+
 END_UPP_NAMESPACE
 
 #endif
diff --git a/uppsrc/ScatterDraw/Equation.cpp b/uppsrc/ScatterDraw/Equation.cpp
index 635e6b093..e1f253d56 100644
--- a/uppsrc/ScatterDraw/Equation.cpp
+++ b/uppsrc/ScatterDraw/Equation.cpp
@@ -334,6 +334,89 @@ String EvalExpr::EvalStr(String line, int numDigits) {
 	}
 }
 
+
+ExplicitEquation::FitError SplineEquation::Fit(DataSource &data, double &r2)
+{	
+	Vector<Pointf> seriesRaw;
+	for (int64 i = 0; i < data.GetCount(); ++i) {		// Remove Nulls	
+		if (!IsNull(data.x(i)) && !IsNull(data.y(i)))
+			seriesRaw << Pointf(data.x(i), data.y(i));
+	}
+
+	if(seriesRaw.IsEmpty())
+        return InadequateDataSource;
+        	
+	PointfLess less;
+	Sort(seriesRaw, less);								// Sort
+	
+	Vector<Pointf> series;
+	for (int i = 1; i < seriesRaw.GetCount(); ++i) {	// Remove points with duplicate x
+		if (seriesRaw[i].x != seriesRaw[i - 1].x)
+			series << seriesRaw[i];	
+	}
+
+	r2 = 0;
+	
+    int n = int(series.GetCount()) - 1;
+    
+    Buffer<double> h(n);
+    for(int i = 0; i < n; ++i)
+        h[i] = (series[i+1].x - series[i].x);
+
+    Buffer<double> alpha(n);
+    for(int i = 1; i < n; ++i)
+        alpha[i] = (3.*(series[i+1].y - series[i].y)/h[i] - 3*(series[i].y - series[i-1].y)/h[i-1]);
+
+    Buffer<double> c(n+1), l(n+1), mu(n+1), z(n+1);
+    l[0] = 1;
+    mu[0] = 0;
+    z[0] = 0;
+
+    for(int i = 1; i < n; ++i) {
+        l[i] = 2.*(series[i+1].x - series[i-1].x) - h[i-1]*mu[i-1];
+        mu[i] = h[i]/l[i];
+        z[i] = (alpha[i] - h[i-1]*z[i-1])/l[i];
+    }
+
+    l[n] = 1.;
+    z[n] = 0;
+    c[n] = 0;
+
+	Buffer<double> b(n), d(n);
+    for(int i = n-1; i >= 0; --i) {
+        c[i] = z[i] - mu[i] * c[i+1];
+        b[i] = (series[i+1].y - series[i].y)/h[i] - h[i]*(c[i+1] + 2*c[i])/3.;
+        d[i] = (c[i+1] - c[i])/3./h[i];
+    }
+
+	ncoeff = n;
+    coeff.Alloc(ncoeff);
+    for(int i = 0; i < n; ++i) {
+        coeff[i].x = series[i].x;
+        coeff[i].a = series[i].y;
+        coeff[i].b = b[i];
+        coeff[i].c = c[i];
+        coeff[i].d = d[i];
+    }
+    return NoError;
+}
+
+double SplineEquation::f(double x)
+{
+    int j;
+    for (j = 0; j < ncoeff; j++) {
+        if(coeff[j].x > x) {
+            if(j == 0)
+                j++;
+            break;
+        }
+    }
+    j--;
+
+    double dx = x - coeff[j].x;
+    return coeff[j].a + coeff[j].b*dx + coeff[j].c*dx*dx + coeff[j].d*dx*dx*dx;
+}
+
 INITBLOCK {
 	ExplicitEquation::Register<LinearEquation>("LinearEquation");
 	ExplicitEquation::Register<PolynomialEquation2>("PolynomialEquation2");
diff --git a/uppsrc/ScatterDraw/Equation.h b/uppsrc/ScatterDraw/Equation.h
index e46db2e09..35310cd79 100644
--- a/uppsrc/ScatterDraw/Equation.h
+++ b/uppsrc/ScatterDraw/Equation.h
@@ -18,7 +18,7 @@ public:
 		ImproperInputParameters = -3,
 		TooManyFunctionEvaluation = -4
 	};
-	FitError Fit(DataSource &series, double &r2);
+	virtual FitError Fit(DataSource &series, double &r2);
 	FitError Fit(DataSource &series)		{double dummy; return Fit(series, dummy);}
 	virtual void GuessCoeff(DataSource &series)	= 0;
 
@@ -225,6 +225,23 @@ public:
 	void SetDegree(int num)				{NEVER();}
 };
 
+class SplineEquation : public ExplicitEquation {
+public:
+	SplineEquation() 					{}
+	double f(double x);
+	virtual String GetName() 			{return t_("Spline");}
+	void SetDegree(int num)				{NEVER();}
+	void GuessCoeff(DataSource &series)	{NEVER();}
+	String GetEquation(int)				{return t_("Spline");}
+	FitError Fit(DataSource &series, double &r2);
+	FitError Fit(DataSource &series)	{double dummy; return Fit(series, dummy);}
+		
+private:
+	struct Coeff{double a, b, c, d, x;};
+    Buffer<Coeff> coeff;
+    int ncoeff;
+};
+
 
 class EvalExpr {
 public:
diff --git a/uppsrc/ScatterDraw/ScatterDraw.cpp b/uppsrc/ScatterDraw/ScatterDraw.cpp
index 9922ca3a6..427f49702 100644
--- a/uppsrc/ScatterDraw/ScatterDraw.cpp
+++ b/uppsrc/ScatterDraw/ScatterDraw.cpp
@@ -241,18 +241,19 @@ void ScatterDraw::DrawLegend(Draw& w, const Size &size, int scale) const {
 	}
 	Font italic = scaledFont;
 	italic.Italic();
+	scaledFont.Bold();
 	for(int row = 0, start = 0; row <= nrows; row++) {
 		for(int i = start; i < min(start + nlr, nlab); i++) {
 			int lx = rect.left + (i - start)*legendWidth + xWidth;
 			int ly = (rowIncSign >= 0 ? rect.top : rect.bottom) +
 					 rowIncSign*int(rowHeight*(row + 0.6) + loclegendRowSpacing*(row + 0.5));
-			Vector <Point> vp;
-			vp << Point(lx, ly) << Point(lx + lineLen, ly);
+			Vector <Point> line;
+			line << Point(lx, ly) << Point(lx + lineLen, ly);
 			if (series[i].opacity > 0 && series[i].seriesPlot)
-				DrawPolylineOpa(w, vp, scale, 1, scale*series[i].thickness, series[i].color, series[i].dash);
-			Point p(lx + scale*7, ly);
+				DrawPolylineOpa(w, line, scale, 1, series[i].thickness, series[i].color, series[i].dash);
+			Point mark_p(lx + scale*7, ly);
 			if (series[i].markWidth >= 1 && series[i].markPlot)
-				series[i].markPlot->Paint(w, scale, p, series[i].markWidth, series[i].markColor, 
+				series[i].markPlot->Paint(w, scale, mark_p, series[i].markWidth, series[i].markColor, 
 					series[i].markBorderWidth, series[i].markBorderColor);   
 			Font &font = series[i].primaryY ? scaledFont : italic;
 			DrawText(w, lx + lineLen + xWidth, ly - scale*6, 0, legends[i], font, series[i].color);                   
@@ -1749,7 +1750,7 @@ void DrawPolylineOpa(Draw& w, const Vector<Point> &p, int scale, double opacity,
 	ASSERT(!p.IsEmpty());
 	Color color = GetOpaqueColor(_color, background, opacity) ;
 	if (dash == LINE_SOLID) 
-		w.DrawPolyline(p, fround(thick), color);
+		w.DrawPolyline(p, fround(thick*scale), color);
 	else {
 		Vector <double> &pat = GetDashedArray(dash);
 		if (pat.IsEmpty())
@@ -1769,7 +1770,7 @@ void DrawPolylineOpa(Draw& w, const Vector<Point> &p, int scale, double opacity,
 				++i;
 			}
 			if (Even(iPat)) 
-				w.DrawLine(begin, end, fround(thick), color);
+				w.DrawLine(begin, end, fround(thick*scale), color);
 			if (d >= len) {
 				iPat++;
 				if (iPat == pat.GetCount())
diff --git a/uppsrc/ScatterDraw/ScatterDraw.h b/uppsrc/ScatterDraw/ScatterDraw.h
index a1faa5af0..c3a1bbebc 100644
--- a/uppsrc/ScatterDraw/ScatterDraw.h
+++ b/uppsrc/ScatterDraw/ScatterDraw.h
@@ -751,6 +751,8 @@ void ScatterDraw::Plot(T& w, const Size &size, int scale)
 	if (drawVGrid) {
 		if (!isPolar) {
 			double x0 = plotW*xMinUnit/xRange;
+			if ((xRange - xMinUnit)/xMajorUnit > 20)
+				xMajorUnit = (xRange - xMinUnit)/20.;
 			for(int i = 0; xMinUnit + i*xMajorUnit < xRange; i++) {
 				int xg = fround(x0 + i*plotW/d1);
 				if (xg > 2*gridWidth && xg < plotW - 2*gridWidth)
@@ -767,6 +769,8 @@ void ScatterDraw::Plot(T& w, const Size &size, int scale)
 	if (drawHGrid) {
 		if (!isPolar) {
 			double y0 = -plotH*yMinUnit/yRange + plotH;
+			if ((yRange - yMinUnit)/yMajorUnit > 20)
+				yMajorUnit = (yRange - yMinUnit)/20.;
 			for(int i = 0; yMinUnit + i*yMajorUnit < yRange; i++) {
 				int yg = fround(y0 - i*plotH/d2);
 				if (yg > 2*gridWidth && yg < plotH - 2*gridWidth) 
diff --git a/uppsrc/ScatterDraw/ScatterDraw.t b/uppsrc/ScatterDraw/ScatterDraw.t
index 902fc4a3a..fd8d3f654 100644
--- a/uppsrc/ScatterDraw/ScatterDraw.t
+++ b/uppsrc/ScatterDraw/ScatterDraw.t
@@ -68,3 +68,9 @@ caES("Racional_1")
 esES("Racional_1")
 euES("")
 frFR("")
+
+T_("Spline")
+caES("")
+esES("")
+euES("")
+frFR("")
diff --git a/uppsrc/ScatterDraw/SeriesPlot.h b/uppsrc/ScatterDraw/SeriesPlot.h
index 401e189c3..09ec3d625 100644
--- a/uppsrc/ScatterDraw/SeriesPlot.h
+++ b/uppsrc/ScatterDraw/SeriesPlot.h
@@ -153,4 +153,5 @@ public:
 	}
 };	
 
+
 #endif