function?ncquiverref（xyuvunitsreftyperefvecveccolcont）
%?NCQUIVERREF:?Vector?plotting?function?for?either?map?or?Cartesian?axes.
%?function?ncquiverref（xyuvunitsreftyperefvecveccolcont）
%?This?function?is?a?substitute?for?the?standard?version?of?quiver
%?and?quiverm?available?using?a?vanilla?release?of?matlab.?This?version
%?assumes?a?2D?vector?field?being?plotted?using?a?gridded?flow?field?
%?from?numerical?models?with?a?regular?geometry.?The?function?enables
%?the?scaling?of?vectors?according?to?a?reference?vector?plotted?in?the?
%?lower?right?hand?corner?of?the?plot?axes.?The?function?works?for?both
%?map?and?Cartesian?axes?and?allows?the?color?of?vectors?to?be?changed.
%?
%?If?a?reference?value?is?not?provided?the?reference?value?is?calculated?
%?by?rounding?the?median?or?maximum?lengths?of?the?quiver?vectors?to?the?
%?first?significant?digit.?Scaling?of?vectors?still?occurs?even?
%?if?the?reference?vector?plotting?is?switched?off.?This?enables
%?different?subplots?to?share?identical?scaling?so?that?the?relative
%?magnitude?of?vectors?can?be?compared?between?subplots?（provided?they?
%?share?the?same?grid）.?
%
%?The?function?includes?the?ability?to?plot?color?vectors?all?of?equal
%?length?but?color?coded?according?to?their?magnitude.?In?this?case?a?
%?colorbar?is?provided?complete?with?units?and?no?scaling?vector?is?
%?plotted.
%
%?Input:
%?x???????-?x-coordinate?or?latitude
%
%?y???????-?y-coordinate?or?longitude
%
%?u???????-?u-component?（Cartesian?+x-direction?map?+longitude-direction）
%
%?v???????-?v-component?（Cartesian?+y-direction?map?+latitude-direction）
%
%?units???-?a?string?providing?the?units?of?the?vector?field.??This?assumes
%???????????the?default?Tex?or?Latex?interpreter?is?being?used?as?set?
%???????????elsewhere?using?set（0‘DefaultTextInterpreter‘‘tex‘）.
%
%?reftype?-?character?variable?specifying?the?type?of?reference?vector.
%???????????Allowable?values?are?‘median‘?for?giving?a?reference
%???????????vector?based?on?the?median?or?‘max‘?for?giving?the
%???????????reference?vector?based?on?the?maximum.??This?argument?may?
%???????????be?omitted?with?‘max‘?as?the?default.?If?reftype?is?entered?
%???????????as?a?number?then?this?is?the?value?of?the?reference?vector?
%???????????in?the?units?of?the?data?in?u?and?v.?If?veccol?is?set?to
%???????????‘col‘?this?argument?has?no?effect?and?should?be?entered
%???????????only?as?a?dummy?argument.
%
%?refvec??-?logical?that?turns?off?or?on?the?plotting?of?the?reference
%???????????vector?scale?for?plotting?vectors.??The?default?is?‘true‘.
%
%?veccol??-?color?of?the?vectors?to?be?plotted.??This?may?either?be?in?the
%???????????form?of?RGB?or?as?a?single?letter?such?as?‘b‘?for?blue
%???????????using?standard?Matlab?color?specifications.?This?may?be?set
%???????????to?‘col‘?if?the?vectors?are?to?be?color?coded?by?magnitude
%???????????instead?of?sized?by?magnitude.?In?this?case?all?vectors
%???????????have?the?same?size?based?on?the?optimum?value?for?the?grid
%