Index: /issm/trunk-jpl/src/c/Container/Observations.cpp
===================================================================
--- /issm/trunk-jpl/src/c/Container/Observations.cpp	(revision 12225)
+++ /issm/trunk-jpl/src/c/Container/Observations.cpp	(revision 12226)
@@ -32,12 +32,12 @@
 }
 /*}}}*/
-/*FUNCTION Observations::Observations(double* observations_list,double* x,double* y,int n){{{*/
-Observations::Observations(double* observations_list,double* x,double* y,int n){
+/*FUNCTION Observations::Observations(double* observations_list,double* x,double* y,int n,Options* options){{{*/
+Observations::Observations(double* observations_list,double* x,double* y,int n,Options* options){
 
 	/*Intermediaries*/
-	int          i;
+	int          i,maxdepth;
 	int          xi,yi;
 	double       xmin,xmax,ymin,ymax;
-	double       offset;
+	double       offset,minlength;
 	Observation *observation = NULL;
 
@@ -52,14 +52,34 @@
 	offset=0.05*(ymax-ymin); ymin-=offset; ymax+=offset;
 
+	/*Get Minimum box size*/
+	if(options->GetOption("boxlength")){
+		options->Get(&minlength,"boxlength");
+		if(minlength<=0)_error_("boxlength should be a positive number");
+		maxdepth=int(log(max(xmax-xmin,ymax-ymin)/minlength +1)/log(2));
+	}
+	else{
+		maxdepth = 30;
+		minlength=max(xmax-xmin,ymax-ymin)/double((1L<<maxdepth)-1);
+	}
+
+
 	/*Initialize Quadtree*/
-	this->quadtree = new Quadtree(xmin,xmax,ymin,ymax,30);
+	printf("Generating quadtree with a maximum box size %g (depth=%i)...",minlength,maxdepth);
+	this->quadtree = new Quadtree(xmin,xmax,ymin,ymax,maxdepth);
 
 	/*Add observations one by one*/
+	int level;
 	for(i=0;i<n;i++){
 		this->quadtree->IntergerCoordinates(&xi,&yi,x[i],y[i]);
-		observation = new Observation(x[i],y[i],xi,yi,observations_list[i]);
-		this->quadtree->Add(observation);
-		this->AddObject(observation);
+		this->quadtree->QuadtreeDepth2(&level,xi,yi);
+		if((int)level >= maxdepth){
+		}
+		else{
+			observation = new Observation(x[i],y[i],xi,yi,observations_list[i]);
+			this->quadtree->Add(observation);
+			this->AddObject(observation);
+		}
 	}
+	printf("done\n");
 }
 /*}}}*/
@@ -105,9 +125,10 @@
 void Observations::QuadtreeColoring(double* A,double *x,double *y,int n){
 
-	int xi,yi;
+	int xi,yi,level;
 
 	for(int i=0;i<n;i++){
 		this->quadtree->IntergerCoordinates(&xi,&yi,x[i],y[i]);
-		this->quadtree->QuadtreeColoring(&A[i],xi,yi);
+		this->quadtree->QuadtreeDepth(&level,xi,yi);
+		A[i]=(double)level;
 	}
 
Index: /issm/trunk-jpl/src/c/Container/Observations.h
===================================================================
--- /issm/trunk-jpl/src/c/Container/Observations.h	(revision 12225)
+++ /issm/trunk-jpl/src/c/Container/Observations.h	(revision 12226)
@@ -8,4 +8,5 @@
 class Obsevration;
 class Quadtree;
+class Options;
 
 class Observations: public DataSet{
@@ -18,5 +19,5 @@
 		/*constructors, destructors*/
 		Observations();
-		Observations(double* observations_list,double* x,double* y,int n);
+		Observations(double* observations_list,double* x,double* y,int n,Options* options);
 		~Observations();
 
Index: /issm/trunk-jpl/src/c/modules/Krigingx/Krigingx.cpp
===================================================================
--- /issm/trunk-jpl/src/c/modules/Krigingx/Krigingx.cpp	(revision 12225)
+++ /issm/trunk-jpl/src/c/modules/Krigingx/Krigingx.cpp	(revision 12226)
@@ -40,5 +40,5 @@
 
 	/*Process observation dataset*/
-	observations=new Observations(obs_list,obs_x,obs_y,obs_length);
+	observations=new Observations(obs_list,obs_x,obs_y,obs_length,options);
 
 	/*Allocation output*/
Index: /issm/trunk-jpl/src/c/objects/Kriging/Quadtree.cpp
===================================================================
--- /issm/trunk-jpl/src/c/objects/Kriging/Quadtree.cpp	(revision 12225)
+++ /issm/trunk-jpl/src/c/objects/Kriging/Quadtree.cpp	(revision 12226)
@@ -312,6 +312,6 @@
 	return newbox;
 }/*}}}*/
-/*FUNCTION Quadtree::QuadtreeColoring{{{1*/
-void Quadtree::QuadtreeColoring(double* A,int xi,int yi){
+/*FUNCTION Quadtree::QuadtreeDepth{{{1*/
+void Quadtree::QuadtreeDepth(int* A,int xi,int yi){
 
 	QuadtreeBox **pbox = NULL;
@@ -336,4 +336,57 @@
 		/*This box is not empty, add one level*/
 		level+=1;
+	}
+
+	*A=level;
+}/*}}}*/
+/*FUNCTION Quadtree::QuadtreeDepth2{{{1*/
+void Quadtree::QuadtreeDepth2(int* A,int xi,int yi){
+
+	QuadtreeBox **pbox = NULL;
+	QuadtreeBox  *box  = NULL;
+	int           level,levelbin;
+
+	/*Initialize levels*/
+	level    = 0;
+	levelbin = (1L<<this->MaxDepth);// = 2^30
+
+	/*Get inital box (the largest)*/
+	pbox=&root;
+
+	/*Find the smallest box where this point is located*/
+	while((box=*pbox) && (box->nbitems<0)){ 
+
+		levelbin>>=1; level+=1; 
+
+		pbox = &box->box[IJ(xi,yi,levelbin)];
+	}
+	if(box && box->nbitems>0){
+		/*This box is not empty, add one level*/
+		level+=1;
+	}
+
+	/*If we were to add the vertex, get level*/
+	if(box && box->nbitems==4){
+		int ij;
+		bool flag=true;
+		while(flag){
+
+			levelbin>>=1; level+=1;
+			if(level>this->MaxDepth){
+				level+=1;
+				break;
+			}
+
+			/*loop over the four observations*/
+			ij=IJ(box->obs[0]->xi,box->obs[0]->yi,levelbin);
+			for (int k=1;k<4;k++){
+				if(IJ(box->obs[k]->xi,box->obs[k]->yi,levelbin) != ij){
+					flag = false;
+				}
+			}
+			if(IJ(xi,yi,levelbin)!=ij){
+				flag = false;
+			}
+		}
 	}
 
Index: /issm/trunk-jpl/src/c/objects/Kriging/Quadtree.h
===================================================================
--- /issm/trunk-jpl/src/c/objects/Kriging/Quadtree.h	(revision 12225)
+++ /issm/trunk-jpl/src/c/objects/Kriging/Quadtree.h	(revision 12226)
@@ -53,5 +53,6 @@
 		QuadtreeBox *NewQuadtreeBox(double xcenter,double ycenter,double length);
 		QuadtreeBox *NewQuadtreeBox(QuadtreeBox* master,int index);
-		void         QuadtreeColoring(double *A,int xi,int yi);
+		void         QuadtreeDepth(int *A,int xi,int yi);
+		void         QuadtreeDepth2(int *A,int xi,int yi);
 };
 #endif //_QUADTREEK_H