function degx(s)

% puts degrees and E/W or N/S signs on the x axis
% degx(s) s is an optional string if s~=[] puts N/S instead of E/W

if nargin~=0, 
 s1='N'; s2='S';
else
 s1='E'; s2='W';
end

xtn=get(gca,'XTick');
xts=get(gca,'XTickLabel');

if sum(str2num(xts)>180)~=0,
  xts=num2str(xtn'-360*(xtn'>180));
end

xts2=num2str(abs(str2num(xts)));
xts2=[xts2 xts2(:,1) xts2(:,1)]; % add two dummy columns for the degree & E/W
[mx,nx]=size(xts2);

for i=1:mx,
  if(str2num(xts(i,:))>0)&(abs(str2num(xts(i,:)))~=180),
    xts2(i,:)=[xts2(i,1:nx-2) char(176) s1];
  elseif(str2num(xts(i,:))<0)&(abs(str2num(xts(i,:)))~=180),
    xts2(i,:)=[xts2(i,1:nx-2) char(176) s2];
  elseif(str2num(xts(i,:))==0)|(abs(str2num(xts(i,:)))==180),
    xts2(i,:)=[xts2(i,1:nx-2) char(176) ' '];
  end 
end

set(gca,'XTickMode','manual');
set(gca,'XTick',xtn);
set(gca,'XTickLabelMode','manual');
set(gca,'XTickLabel',xts2);