diff --git a/modules/gmt/modgmt_func.h b/modules/gmt/modgmt_func.h
index f6701ba..6919a27 100644
--- a/modules/gmt/modgmt_func.h
+++ b/modules/gmt/modgmt_func.h
@@ -195,7 +195,7 @@ class Base2CoordD: public DefaultConverter<Base2Coord>
 };
 
 // Convertors for double non-negative value
-class Base2NonNeg: public Base2Double
+class Base2Pos: public Base2Double
 {
  public:
  double Convert(const ObjectBase* ob, bool* res, std::string& err)
@@ -209,7 +209,7 @@ class Base2NonNeg: public Base2Double
   return t;
  }
 };
-using Base2NonNegD=DefaultConverter<Base2NonNeg>;
+using Base2PosD=DefaultConverter<Base2Pos>;
 
 // Convertors for double values which must be in some interval
 template<int32_t Min, int32_t Max>
@@ -383,7 +383,7 @@ class Convert2Struct<struct gmt_projection, ObjectList>
    ONFPar<Base2Proj,ObjectGMTProjection> proj("projection");
    ONFPar<Base2Region,ObjectGMTRegion> region("region");
    ONPar<Base2StringD> type("[projection][( |_)]t[ype]","mercator");
-   ONPar<Base2NonNegD> width("width",gmt_projection::default_width),height("height",gmt_projection::default_width);
+   ONPar<Base2PosD> width("width",gmt_projection::default_width),height("height",gmt_projection::default_width);
 
    {ParseNamedParameters params(input,type,region,proj,width,height); if(!params) {err=params.Error(); goto fail;}} // Fail to parse by variant 3
 
@@ -433,7 +433,7 @@ class Convert2Struct<struct gmt_projection, ObjectList>
     }
     case(gmt_projection::TRANSMERCATOR): // t Parameters: central meridian (cmer, default is center of region), latitude of origin (orlat, default is 0.0), scale factor (scale, default is 1.0)
     {
-     ONPar<Base2NonNegD> scale("scale",1.0);
+     ONPar<Base2PosD> scale("scale",1.0);
      ONPar<Base2CoordD> orlat("(l[atitude][( |_)][of( |_)]origin|o[rigin][( |_)]latitude)",0.0);
      {ParseNamedParameters apar(input,cmer,scale,orlat); if(!apar) {err=apar.Error(); goto fail;}} // Fail to parse additional parameters
      if( cmer.Exist() || changetype) p.t.cmer =cmer;
@@ -572,7 +572,7 @@ class Convert2Struct<struct gmt_projection, ObjectList>
 
   {
    RPosPar<Base2String> type("projection type");
-   RPosPar<Base2NonNeg> width("width");
+   RPosPar<Base2Pos> width("width");
    RPosPar<Base2Region> region("region");
 
    {ParsePositionalParameters params(input,0,3,type,width,region); if(!params) {err=params.Error(); goto fail;}} // Fail to parse by variant 4
@@ -586,7 +586,7 @@ class Convert2Struct<struct gmt_projection, ObjectList>
    {
     case(gmt_projection::XY): // x Parameter 4 is height (by default equal width)
     {
-     OPosPar<Base2NonNegD> height("height",p.width);
+     OPosPar<Base2PosD> height("height",p.width);
      {ParsePositionalParameters params(input,3,input->Size(),height); if(!params) {err=params.Error(); goto fail;}} // Fail to parse additional parameters
      p.x.height=height;
      break;
@@ -611,7 +611,7 @@ class Convert2Struct<struct gmt_projection, ObjectList>
     {
      OPosPar<Base2CoordD> cmer("central meridian",(p.region.xb+p.region.xe)*0.5);
      OPosPar<Base2CoordD> orlat("latitude of origin",0.0);
-     OPosPar<Base2NonNegD> scale("scale",1.0);
+     OPosPar<Base2PosD> scale("scale",1.0);
      {ParsePositionalParameters params(input,3,input->Size(),cmer,orlat,scale); if(!params) {err=params.Error(); goto fail;}} // Fail to parse additional parameters
      p.t.cmer=cmer; p.t.orlat=orlat; p.t.scale=scale;
      break;