diff --git a/modules/gmt/modgmt_objects.h b/modules/gmt/modgmt_objects.h
index 5835f29..a232194 100644
--- a/modules/gmt/modgmt_objects.h
+++ b/modules/gmt/modgmt_objects.h
@@ -133,7 +133,7 @@ class ObjectGMTLayer: public ObjectBase
  {
   if(Shifted())
   {
-   std::string b="V "+std::to_string(cm2GMT(shiftx))+" "+std::to_string(cm2GMT(shifty))+" T\n";
+   std::string b="V "+ToString(cm2GMT(shiftx))+" "+ToString(cm2GMT(shifty))+" T\n";
    std::string e="U\n";
    int8_t* p=new int8_t[b.size()+data->size()+e.size()];
    memcpy(p,b.data(),b.size());
diff --git a/modules/gmt/modgmt_structs.h b/modules/gmt/modgmt_structs.h
index 4d0c849..40cefe1 100644
--- a/modules/gmt/modgmt_structs.h
+++ b/modules/gmt/modgmt_structs.h
@@ -98,8 +98,8 @@ struct gmt_coord: public gmt_struct
 
  std::string Value() const
  {
-  if(!isdeg) return std::to_string(r);
-  else return (sign?"":"-")+std::to_string(d)+":"+std::to_string(m)+(s==0?"":":"+std::to_string(s));
+  if(!isdeg) return ToString(r);
+  else return (sign?"":"-")+ToString(d)+":"+ToString(m)+(s==0?"":":"+ToString(s));
  }
  operator double() const
  {
@@ -254,24 +254,24 @@ struct gmt_projection: public gmt_struct
   std::string ret;
   switch(proj)
   {
-   case(XY): {ret="-JX"+std::to_string(width)+"c/"+std::to_string(x.height)+"c"; break;}
-   case(CYL_EQU): {ret="-JQ"+q.cmer.Value()+"/"+q.stpar.Value()+"/"+std::to_string(width)+"c"; break;}
-   case(MERCATOR): {ret="-JM"+m.cmer.Value()+"/"+m.stpar.Value()+"/"+std::to_string(width)+"c"; break;}
-   case(TRANSMERCATOR): {ret="-JT"+t.cmer.Value()+"/"+t.orlat.Value()+"/"+std::to_string(width)+"c --PROJ_SCALE_FACTOR="+std::to_string(t.scale); break;}
+   case(XY): {ret="-JX"+ToString(width)+"c/"+ToString(x.height)+"c"; break;}
+   case(CYL_EQU): {ret="-JQ"+q.cmer.Value()+"/"+q.stpar.Value()+"/"+ToString(width)+"c"; break;}
+   case(MERCATOR): {ret="-JM"+m.cmer.Value()+"/"+m.stpar.Value()+"/"+ToString(width)+"c"; break;}
+   case(TRANSMERCATOR): {ret="-JT"+t.cmer.Value()+"/"+t.orlat.Value()+"/"+ToString(width)+"c --PROJ_SCALE_FACTOR="+ToString(t.scale); break;}
    case(OBLIQMERCATOR):
    {
     switch(o.type)
     {
-     case(OType::A): {ret="-JOa"+o.clon.Value()+"/"+o.clat.Value()+"/"+o.azimuth.Value()+"/"+std::to_string(width)+"c"; break;}
-     case(OType::B): {ret="-JOb"+o.clon.Value()+"/"+o.clat.Value()+"/"+o.eqlon.Value()+"/"+o.eqlat.Value()+"/"+std::to_string(width)+"c"; break;}
-     case(OType::C): {ret="-JOb"+o.clon.Value()+"/"+o.clat.Value()+"/"+o.polelon.Value()+"/"+o.polelat.Value()+"/"+std::to_string(width)+"c"; break;}
+     case(OType::A): {ret="-JOa"+o.clon.Value()+"/"+o.clat.Value()+"/"+o.azimuth.Value()+"/"+ToString(width)+"c"; break;}
+     case(OType::B): {ret="-JOb"+o.clon.Value()+"/"+o.clat.Value()+"/"+o.eqlon.Value()+"/"+o.eqlat.Value()+"/"+ToString(width)+"c"; break;}
+     case(OType::C): {ret="-JOb"+o.clon.Value()+"/"+o.clat.Value()+"/"+o.polelon.Value()+"/"+o.polelat.Value()+"/"+ToString(width)+"c"; break;}
      default: return "";
     }
    }
-   case(CASSINI): {ret="-JC"+c.clon.Value()+"/"+c.clat.Value()+"/"+std::to_string(width)+"c"; break;}
-   case(CYL_EQA): {ret="-JY"+y.stpar.Value()+"/"+y.cmer.Value()+"/"+std::to_string(width)+"c"; break;}
-   case(MILLER): {ret="-JJ"+j.cmer.Value()+"/"+std::to_string(width)+"c"; break;}
-   case(CYL_STERE): {ret="-JCyl_stere"+cyl_stere.stpar.Value()+"/"+cyl_stere.cmer.Value()+"/"+std::to_string(width)+"c"; break;}
+   case(CASSINI): {ret="-JC"+c.clon.Value()+"/"+c.clat.Value()+"/"+ToString(width)+"c"; break;}
+   case(CYL_EQA): {ret="-JY"+y.stpar.Value()+"/"+y.cmer.Value()+"/"+ToString(width)+"c"; break;}
+   case(MILLER): {ret="-JJ"+j.cmer.Value()+"/"+ToString(width)+"c"; break;}
+   case(CYL_STERE): {ret="-JCyl_stere"+cyl_stere.stpar.Value()+"/"+cyl_stere.cmer.Value()+"/"+ToString(width)+"c"; break;}
    default: return "";
   }
   ret+=" "+region.Value();
@@ -310,13 +310,13 @@ struct gmt_color: public gmt_struct
  double transparency;
  std::string Value() const
  {
-  std::string trans=(transparency!=0)?("@"+std::to_string(transparency)):"";
+  std::string trans=(transparency!=0)?("@"+ToString(transparency)):"";
   switch(model)
   {
-   case(RGB): return std::to_string(r)+"/"+std::to_string(g)+"/"+std::to_string(b)+trans;
-   case(GRAY): return std::to_string(gray)+trans;
-   case(HSV): return std::to_string(hue)+"-"+std::to_string(saturation)+"-"+std::to_string(value)+trans;
-   case(CMYK): return std::to_string(cyan)+"/"+std::to_string(magenta)+"/"+std::to_string(yellow)+"/"+std::to_string(black)+trans;
+   case(RGB): return ToString(r)+"/"+ToString(g)+"/"+ToString(b)+trans;
+   case(GRAY): return ToString(gray)+trans;
+   case(HSV): return ToString(hue)+"-"+ToString(saturation)+"-"+ToString(value)+trans;
+   case(CMYK): return ToString(cyan)+"/"+ToString(magenta)+"/"+ToString(yellow)+"/"+ToString(black)+trans;
   }
   return "";
  }
@@ -620,9 +620,9 @@ struct gmt_dash: public gmt_struct
  {
   std::string ret;
   if(dash.empty()) return ret;
-  for(auto i:dash) ret+=std::to_string((wisrel?width:1.0)*i/10.0)+"_";
+  for(auto i:dash) ret+=ToString((wisrel?width:1.0)*i/10.0)+"_";
   ret.back()=':';
-  ret+=std::to_string(shift)+"c";
+  ret+=ToString(shift)+"c";
   return ret;
  }
  operator bool() const {return !dash.empty();}
@@ -679,7 +679,7 @@ struct gmt_pen: public gmt_struct
  struct gmt_color color;
  struct gmt_dash dash;
  static const double default_width;
- std::string Value() const {return std::to_string(width/10.0)+"c,"+color.Value()+(dash?(","+dash.Value()):"");}
+ std::string Value() const {return ToString(width/10.0)+"c,"+color.Value()+(dash?(","+dash.Value()):"");}
 
  // Interpret one numeric argument as width value
  bool Convert(double in)