add mask nan

7 files changed, 196 insertions, 12 deletions

diff --git a/ds9/doc/ref/command.html b/ds9/doc/ref/command.html
index 33e438a..baecde8 100644
--- a/ds9/doc/ref/command.html
+++ b/ds9/doc/ref/command.html
@@ -449,6 +449,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [filter &lt;string&gt;]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; [&lt;ref&gt;]
         [filter load &lt;filename&gt;]</tt><tt><br>
@@ -462,6 +463,7 @@
 
 
 
+
         [&lt;ref&gt;] [match]</tt><tt><br>
       </tt><tt> </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt>
       </tt><tt>[&lt;ref&gt;] [match error &lt;value&gt;
@@ -479,6 +481,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [panto yes|no]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         [&lt;ref&gt;] [plot &lt;xcol&gt; &lt;ycol&gt; &lt;xerrcol&gt;
@@ -504,6 +507,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [save &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         [&lt;ref&gt;] [server</tt><tt> </tt><tt>cds|adac|cadc|cambridge|sao|ukirt|iucaa|bejing|saao]</tt><tt><br>
@@ -529,11 +533,13 @@
       </tt><tt> &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[&lt;ref&gt;]
 
 
+
         [symbol shape</tt><tt> </tt><tt>circle point|box point|diamond
         point|</tt><tt>cross point|x point|arrow point|boxcircle point]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [symbol add| [#] remove]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [&lt;ref&gt;]
         [symbol save|load &lt;filename&gt;]</tt><tt><br>
@@ -581,6 +587,7 @@
       </tt><tt> $ds9 -catalog panto no</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>$ds9 -catalog plot</tt><tt> </tt><tt>'\$Jmag'
 
+
         '\$Hmag' '\$e_Jmag' '\$e_Hmag'</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>$ds9 -catalog print</tt><tt><br>
       </tt><tt> </tt><tt>$ds9 -catalog psky fk5</tt><tt><br>
@@ -674,6 +681,7 @@
 
 
 
+
           [match]<br>
           &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [lock
           [yes|no]]</tt><br>
@@ -806,6 +814,7 @@
 
 
 
+
         &lt;coordsys&gt;]<br>
         &nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [lock
         &lt;coordsys&gt;|none]</tt><br>
@@ -967,6 +976,7 @@
                     </tt></tt></tt></tt></tt></tt></tt></tt> <tt><tt>$ds9
 
 
+
           -envi foo.hdr foo.bsq</tt></tt><tt><tt><tt><tt><tt><tt><br>
                 </tt></tt></tt></tt></tt></tt>
       <p><b><a name="exit" id="exit"></a>exit<br>
@@ -998,10 +1008,12 @@
       </tt><tt>[big|little</tt><tt>|native]</tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>-export &lt;filename&gt;</tt><tt>.jpeg
 
+
         [1-100]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>-export &lt;filename&gt;</tt><tt>.tiff
 
 
+
         [none|jpeg|packbits|deflate]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;</tt><tt><br>
       </tt><tt> Example:</tt><tt><br>
@@ -1437,7 +1449,7 @@
       <p>Controls mask parameters.</p>
       <tt>Syntax:<br>
         -mask [color &lt;color&gt;]<br>
-        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [mark zero|nonzero|range]<br>
+        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [mark zero|nonzero|nan|nonnan|range]<br>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [range &lt;low&gt; &lt;high&gt;]<br>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [transparency &lt;value&gt;]<br>
       </tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [system
@@ -1465,9 +1477,11 @@
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[crosshair
 
 
+
         &lt;coordsys&gt;]</tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
+
         [crop &lt;coordsys&gt;]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [slice
         &lt;coordsys&gt;]</tt><tt><br>
@@ -1480,6 +1494,7 @@
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [smooth]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
+
         [3d]</tt><tt><br>
       </tt><tt> &nbsp;</tt><tt><br>
       </tt><tt> Example:</tt><tt><br>
@@ -1598,16 +1613,19 @@
 
 
 
+
         [pan]<br>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
 
+
         [crosshair]<br>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
 
+
         [open|close]<br>
         &nbsp;<br>
         Example:<br>
@@ -1717,6 +1735,7 @@
 
 
 
+
         [yes|open]<br>
         &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;
         [no|close]<br>
@@ -1747,6 +1766,7 @@
       </tt><tt> </tt><tt> </tt><tt># existing plot</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>-plot</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
+
         load &lt;filename&gt; xy|xyex|xyey|xyexey]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp; &nbsp;&nbsp;
         [[&lt;plotname&gt;] save &lt;filename&gt;]</tt><tt><br>
@@ -1761,6 +1781,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp; &nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         loadconfig &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp; &nbsp;
         [[&lt;plotname&gt;] saveconfig &lt;filename&gt;]</tt><tt><br>
@@ -1782,9 +1803,11 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp; &nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         close</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp; &nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
+
         mode pointer|zoom]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># configure graph</tt><tt><br>
@@ -1805,6 +1828,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp; &nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         legend yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp; &nbsp;&nbsp;
         [[&lt;plotname&gt;] legend position right|left|top|bottom]</tt><tt><br>
@@ -1827,6 +1851,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp; &nbsp;&nbsp; [</tt><tt>[&lt;plotname&gt;]
 
 
+
         barmode normal|stacked|aligned|overlap]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># configure current dataset</tt><tt><br>
@@ -2009,6 +2034,7 @@
         &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
+
         [color rgb|cmyk|gray]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [level 1|2]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [resolution
@@ -2290,6 +2316,7 @@
 
 
 
+
         [image|table|slice]</tt><br>
       <tt>&nbsp;<br>
         Example:<br>
@@ -2407,6 +2434,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[&lt;ref&gt;]
 
 
+
         [crosshair]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp; [&lt;ref&gt;] [export
         sb|tsv &lt;filename&gt;]</tt><tt><br>
@@ -2429,6 +2457,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[&lt;ref&gt;]
 
 
+
         [update]</tt><tt><br>
       </tt><tt> </tt><tt><br>
       </tt><tt> Example:</tt><tt><br>
@@ -2538,17 +2567,20 @@
 
 
 
+
                   [sigma &lt;value&gt;]<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
 
+
                   [sigmaminor &lt;value&gt;]<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 [angle
 
 
 
+
                       &lt;value&gt;]<br>
                     </tt></tt></tt></tt></tt></tt></tt>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [match]<br>
@@ -2568,10 +2600,12 @@
 
 
 
+
                   sigmaminor 2.0<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt>$ds9
 
 
+
                       -smooth angle 45<br>
                     </tt></tt></tt></tt></tt></tt></tt> $ds9 -smooth
         match<br>
diff --git a/ds9/doc/ref/samp.html b/ds9/doc/ref/samp.html
index e9d4a4a..025e981 100644
--- a/ds9/doc/ref/samp.html
+++ b/ds9/doc/ref/samp.html
@@ -464,6 +464,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [2mass|iras]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         [csc|xmm|rosat]</tt><tt><br>
@@ -504,6 +505,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [filter &lt;string&gt;]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; [&lt;ref&gt;]
         [filter load &lt;filename&gt;]</tt><tt><br>
@@ -517,6 +519,7 @@
 
 
 
+
         [&lt;ref&gt;] [match &lt;ref&gt; &lt;ref&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt>
       </tt><tt>[&lt;ref&gt;] [match error &lt;value&gt;
@@ -534,6 +537,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [panto yes|no]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         [&lt;ref&gt;] [plot &lt;xcol&gt; &lt;ycol&gt; &lt;xerrcol&gt;
@@ -559,6 +563,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [save &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         [&lt;ref&gt;] [server</tt><tt> </tt><tt>cds|adac|cadc|cambridge|sao|ukirt|iucaa|bejing|saao]</tt><tt><br>
@@ -585,6 +590,7 @@
       </tt><tt> &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[&lt;ref&gt;]
 
 
+
         [symbol shape</tt><tt> </tt><tt>circle point|box point|diamond
         point|</tt><tt>cross point|x point|arrow point|boxcircle point]</tt><tt><br>
       </tt><tt> </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
@@ -640,6 +646,7 @@
       </tt><tt> catalog panto no</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>catalog plot</tt><tt> </tt><tt>{$Jmag}
 
+
         {$Hmag} {$e_Jmag} {$e_Hmag}</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>catalog print</tt><tt><br>
       </tt><tt> </tt><tt>catalog psky fk5</tt><tt><br>
@@ -656,6 +663,7 @@
       </tt><tt> </tt><tt>catalog symbol condition</tt><tt> </tt><tt>{$Jmag&gt;15}</tt><tt><br>
       </tt><tt> </tt><tt>catalog symbol 2 shape</tt><tt> </tt><tt>{boxcircle
 
+
         point}</tt><tt><br>
       </tt><tt> </tt><tt>catalog symbol color red</tt><tt><br>
       </tt><tt> catalog symbol font times</tt><tt><br>
@@ -798,6 +806,7 @@
         </tt></tt> <tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
             [save levels &lt;filename&gt;]<br>
           </tt></tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [copy]<br>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [paste
@@ -880,6 +889,7 @@
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [reset]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [3d</tt><tt> </tt><tt>zmin
 
+
         zmax &lt;coordsys&gt;]</tt><tt><br>
       </tt><tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [open|close]</tt><tt><br>
       </tt><tt> &nbsp;</tt><tt><br>
@@ -1615,6 +1625,7 @@
 
 
 
+
           Macros</a> for more information.</p>
       <tt>Syntax:<br>
         iexam []<br>
@@ -1754,7 +1765,7 @@
       <p>Controls mask parameters.</p>
       <tt>Syntax:<br>
         mask [color &lt;color&gt;]<br>
-        &nbsp;&nbsp;&nbsp;&nbsp; [mark zero|nonzero|range]<br>
+        &nbsp;&nbsp;&nbsp;&nbsp; [mark zero|nonzero|nan|nonnan|range]<br>
         &nbsp;&nbsp;&nbsp;&nbsp; [range &lt;low&gt; &lt;high&gt;]<br>
         &nbsp;&nbsp;&nbsp;&nbsp; [transparency &lt;value&gt;]<br>
         &nbsp;&nbsp;&nbsp;&nbsp; [system &lt;coordsys&gt;]<br>
@@ -2121,6 +2132,7 @@
       </tt><tt> </tt><tt> </tt><tt># existing plot</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>plot</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
+
         load &lt;filename&gt; xy|xyex|xyey|xyexey]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] save &lt;filename&gt;]</tt><tt><br>
@@ -2129,18 +2141,22 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         duplicate [#]]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         stats yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         list yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         loadconfig &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] saveconfig &lt;filename&gt;]</tt><tt><br>
@@ -2162,10 +2178,12 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         close</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         mode pointer|zoom]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># configure graph</tt><tt><br>
@@ -2186,6 +2204,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         legend yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] legend position right|left|top|bottom]</tt><tt><br>
@@ -2208,6 +2227,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp; [</tt><tt>[&lt;plotname&gt;]
 
 
+
         barmode normal|stacked|aligned|overlap]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># configure current dataset</tt><tt><br>
@@ -2215,48 +2235,59 @@
         yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
+
         shape circle|square|diamond|plus|splus|scross|triangle|arrow]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         shape fill yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         shape color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         smooth step|linear|cubic|quadratic|catrom]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         width &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         dash yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         error yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         error color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         error width &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         name &lt;string&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># select current dataset</tt><tt><br>
@@ -2958,6 +2989,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [&lt;ref&gt;] [save &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp; &nbsp;&nbsp; &nbsp; [&lt;ref&gt;]
         [radius &lt;value&gt; degrees|arcmin|arcsec]</tt><tt><br>
@@ -3078,21 +3110,25 @@
 
 
 
+
                   [sigma &lt;value&gt;]<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
 
+
                   [sigmaminor &lt;value&gt;]<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 [angle
 
 
 
+
                       &lt;value&gt;]<br>
                     </tt></tt></tt></tt></tt></tt></tt></tt> <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
+
         [match]<br>
         &nbsp;&nbsp;&nbsp; &nbsp;&nbsp; [lock [yes|no]]</tt><br>
       <tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [open|close]<br>
@@ -3116,14 +3152,17 @@
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt>smooth
 
 
+
                         sigma 2.0<br>
                       </tt></tt></tt></tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt>smooth
 
 
+
                         sigmaminor 2.0<br>
                       </tt></tt></tt></tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt><tt><tt><tt>smooth
 
 
+
                               angle 45<br>
                             </tt></tt></tt></tt></tt></tt></tt></tt></tt></tt></tt>
         smooth open<br>
diff --git a/ds9/doc/ref/xpa.html b/ds9/doc/ref/xpa.html
index 8af6b06..8e1fa46 100644
--- a/ds9/doc/ref/xpa.html
+++ b/ds9/doc/ref/xpa.html
@@ -209,6 +209,7 @@
               </tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt>$xpaset
 
 
+
                       -p ds9 3d match</tt></tt></tt></tt></tt></tt></tt></tt><br>
       <tt><tt><tt><tt><tt><tt><tt><tt><tt><tt><tt>$xpaset -p ds9 3d lock
                             yes</tt><br>
@@ -449,6 +450,7 @@
       <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt> <tt>[&lt;ref&gt;]
 
 
+
         [crosshair]</tt><br>
       <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [&lt;ref&gt;] [dec
         &lt;col&gt;]</tt><br>
@@ -470,24 +472,29 @@
 
 
 
+
             [&lt;ref&gt;] [match &lt;ref&gt; &lt;ref&gt;]<br>
           </tt></tt> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt> <tt>[&lt;ref&gt;]
 [match
 
 
 
+
         error &lt;value&gt; degrees|arcmin|arcsec]</tt><br>
       <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt> <tt>[&lt;ref&gt;]
 
 
+
         [match function 1and2|1not2|2not1]<br>
       </tt> <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt> <tt>[&lt;ref&gt;]
 
 
+
         [match return 1and2|1only|2only]</tt><br>
       <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt> <tt>[&lt;ref&gt;]
 
 
+
         [match unique yes|no]</tt><br>
       <tt>&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; [&lt;ref&gt;] [maxrows
         &lt;number&gt;]</tt><br>
@@ -538,9 +545,11 @@
 
 
 
+
           shape</tt></tt> <tt><tt>circle point|box point|diamond point|</tt>cross
 
 
+
         point|x point|arrow point|boxcircle point]<br>
         &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [&lt;ref&gt;] [symbol
         add| [#] remove]<br>
@@ -551,6 +560,7 @@
       </tt> <tt>&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;</tt> <tt>[&lt;ref&gt;]
 
 
+
         [update]</tt><br>
       <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [&lt;ref&gt;] [x
         &lt;col&gt;]</tt><br>
@@ -1079,6 +1089,7 @@
             </tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt><tt>$xpaset
 
 
+
                           -p ds9 export envi foo.hdr foo.bsq little</tt></tt><br>
                     </tt></tt></tt></tt> $xpaset -p ds9 export tiff
               foo.tiff jpeg</tt></tt></tt><br>
@@ -1621,7 +1632,7 @@
       <p>Controls mask parameters.</p>
       <tt>Syntax:<br>
         mask [color &lt;color&gt;]<br>
-        &nbsp;&nbsp;&nbsp;&nbsp; [mark zero|nonzero|range]<br>
+        &nbsp;&nbsp;&nbsp;&nbsp; [mark zero|nonzero|nan|nonnan|range]<br>
         &nbsp;&nbsp;&nbsp;&nbsp; [range &lt;low&gt; &lt;high&gt;]<br>
         &nbsp;&nbsp;&nbsp;&nbsp; [transparency &lt;value&gt;]<br>
       </tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp; [system &lt;coordsys&gt;]<br>
@@ -1966,6 +1977,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[new
 
 
+
         [line|bar|scatter] &lt;title&gt; &lt;xaxis label&gt; &lt;yaxis
         label&gt;</tt><tt> </tt><tt>xy|xyex|xyey|xyexey</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[new</tt><tt>
@@ -1982,9 +1994,11 @@
       </tt><tt>[line|bar|scatter]</tt><tt> </tt><tt>stdin</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[new
 
+
         name &lt;plotname&gt; stdin</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[new
 
+
         name &lt;plotname&gt;</tt><tt> </tt><tt>line|bar|scatter</tt><tt>
       </tt><tt>stdin</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
@@ -1996,6 +2010,7 @@
       </tt><tt> </tt><tt> </tt><tt># existing plot</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>plot</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
+
         load &lt;filename&gt; xy|xyex|xyey|xyexey]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] save &lt;filename&gt;]</tt><tt><br>
@@ -2004,18 +2019,22 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         duplicate [#]]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         stats yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         list yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         loadconfig &lt;filename&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] saveconfig &lt;filename&gt;]</tt><tt><br>
@@ -2037,10 +2056,12 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         close</tt><tt>]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         mode pointer|zoom]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># configure graph</tt><tt><br>
@@ -2061,6 +2082,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         legend yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] legend position right|left|top|bottom]</tt><tt><br>
@@ -2083,6 +2105,7 @@
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp; [</tt><tt>[&lt;plotname&gt;]
 
 
+
         barmode normal|stacked|aligned|overlap]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># configure current dataset</tt><tt><br>
@@ -2090,48 +2113,59 @@
         yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp; &nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
+
         shape circle|square|diamond|plus|splus|scross|triangle|arrow]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         shape fill yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         shape color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         smooth step|linear|cubic|quadratic|catrom]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         width &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         dash yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         error yes|no]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         error color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;
         [[&lt;plotname&gt;] color &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         error width &lt;value&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[[&lt;plotname&gt;]
 
 
+
         name &lt;string&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt># select current dataset</tt><tt><br>
@@ -2815,6 +2849,7 @@
         &lt;ra&gt; &lt;dec&gt; &lt;coordsys&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[&lt;ref&gt;]
 
+
         [crosshair]</tt><tt><br>
       </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp; [&lt;ref&gt;] [export
         sb|tsv &lt;filename&gt;]</tt><tt><br>
@@ -2835,6 +2870,7 @@
         [system &lt;coordsys&gt;]</tt><tt><br>
       </tt><tt> </tt><tt> </tt><tt>&nbsp;&nbsp;&nbsp;</tt><tt> </tt><tt>[&lt;ref&gt;]
 
+
         [update]</tt><br>
       &nbsp; <tt><br>
         Example:<br>
@@ -2939,21 +2975,25 @@
 
 
 
+
                   [sigma &lt;value&gt;]<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 
 
+
                   [sigmaminor &lt;value&gt;]<br>
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 [angle
 
 
 
+
                       &lt;value&gt;]<br>
                     </tt></tt></tt></tt></tt></tt></tt></tt> <tt>&nbsp;&nbsp;&nbsp;
 
 
+
         &nbsp;&nbsp; [match]<br>
         &nbsp;&nbsp;&nbsp; &nbsp;&nbsp; [lock [yes|no]]</tt><br>
       <tt><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [open|close]<br>
@@ -2967,6 +3007,7 @@
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt>$xpaget
 
 
+
                         ds9 smooth sigmaminor<br>
                       </tt></tt></tt></tt></tt></tt></tt></tt> $xpaget
         ds9 smooth lock<br>
@@ -2979,14 +3020,17 @@
                 </tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt>$xpaset
 
 
+
                         -p ds9 smooth sigma 2.0<br>
                       </tt></tt></tt></tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt>$xpaset
 
 
+
                         -p ds9 smooth sigmaminor 2.0<br>
                       </tt></tt></tt></tt></tt></tt></tt></tt></tt> <tt><tt><tt><tt><tt><tt><tt><tt><tt><tt><tt><tt>$xpaset
 
 
+
                               -p ds9 smooth angle 45<br>
                             </tt></tt></tt></tt></tt></tt></tt></tt></tt></tt></tt>
         $xpaset -p ds9 smooth match<br>
diff --git a/ds9/library/marker.tcl b/ds9/library/marker.tcl
index 71e8424..962448f 100644
--- a/ds9/library/marker.tcl
+++ b/ds9/library/marker.tcl
@@ -51,6 +51,8 @@ proc MarkerDef {} {
 
     set marker(format) ds9
 
+    set marker(mask) nonzero
+
     # these are only used for save/load/list and
     #   are set from current wcs values
     array set pmarker [array get marker]
@@ -1257,7 +1259,58 @@ proc MarkerMask {} {
 	return
     }
 
-    $current(frame) marker create mask
+    if {[MarkerMaskParamsDialog]} {
+#	$current(frame) marker create mask $marker(mask)
+    }
+}
+
+proc MarkerMaskParamsDialog {} {
+    global marker
+    global ed
+
+    set w {.markermskd}
+
+    set ed(ok) 0
+    set ed(mask) $marker(mask)
+
+    DialogCreate $w [msgcat::mc {Mask Parameters}] ed(ok)
+
+    # Param
+    set f [ttk::frame $w.param]
+
+    ttk::label $f.marktitle -text [msgcat::mc {Block}]
+    ttk::radiobutton $f.zero -text [msgcat::mc {Zero}] \
+	-variable marker(mask) -value zero
+    ttk::radiobutton $f.nonzero -text [msgcat::mc {Non-zero}] \
+	-variable marker(mask) -value nonzero
+
+    grid $f.marktitle $f.zero $f.nonzero -padx 2 -pady 2 -sticky w
+
+    # Buttons
+    set f [ttk::frame $w.buttons]
+    ttk::button $f.ok -text [msgcat::mc {OK}] -command {set ed(ok) 1} \
+	-default active 
+    ttk::button $f.cancel -text [msgcat::mc {Cancel}] -command {set ed(ok) 0}
+    pack $f.ok $f.cancel -side left -expand true -padx 2 -pady 4
+
+    bind $w <Return> {set ed(ok) 1}
+
+    # Fini
+    ttk::separator $w.sep -orient horizontal
+    pack $w.buttons $w.sep -side bottom -fill x
+    pack $w.param -side top -fill both -expand true
+
+    DialogCenter $w 
+    DialogWait $w ed(ok)
+    DialogDismiss $w
+
+    if {$ed(ok)} {
+	set marker(mask) $ed(mask)
+    }
+
+    set rr $ed(ok)
+    unset ed
+    return $rr
 }
 
 proc MarkerInfo {} {
diff --git a/ds9/library/mask.tcl b/ds9/library/mask.tcl
index f04982b..0c1f0ee 100644
--- a/ds9/library/mask.tcl
+++ b/ds9/library/mask.tcl
@@ -247,21 +247,29 @@ proc MaskParamsDialog {} {
     ttk::label $f.colortitle -text [msgcat::mc {Color}]
     ColorMenuButton $f.colorbutton ed color {}
 
-    ttk::label $f.marktitle -text [msgcat::mc {Block}]
-    ttk::radiobutton $f.zero -text [msgcat::mc {Zero}] \
+    ttk::label $f.marktitle -text [msgcat::mc {Block Pixel}]
+    set mb $f.markbutton.menu
+    ttk::menubutton $f.markbutton -textvariable ed(mark) -menu $mb
+    menu $mb
+    $mb add radiobutton -label [msgcat::mc {Zero}] \
 	-variable ed(mark) -value zero
-    ttk::radiobutton $f.nonzero -text [msgcat::mc {Non-zero}] \
+    $mb add radiobutton -label [msgcat::mc {Non-Zero}] \
 	-variable ed(mark) -value nonzero
-    ttk::radiobutton $f.range -text [msgcat::mc {Range}] \
+    $mb add radiobutton -label [msgcat::mc {NAN}] \
+	-variable ed(mark) -value nan
+    $mb add radiobutton -label [msgcat::mc {Non-NAN}] \
+	-variable ed(mark) -value nonnan
+    $mb add radiobutton -label [msgcat::mc {Range}] \
 	-variable ed(mark) -value range
+
     ttk::label $f.rangetitle -text [msgcat::mc {Range}]
     ttk::entry $f.low -textvariable ed(low) -width 13
     ttk::entry $f.high -textvariable ed(high) -width 13
 
-    grid $f.coordtitle $f.coordbutton - - - -padx 2 -pady 2 -sticky w
-    grid $f.colortitle $f.colorbutton - - - -padx 2 -pady 2 -sticky w
-    grid $f.marktitle $f.zero $f.nonzero $f.range -padx 2 -pady 2 -sticky w
-    grid $f.rangetitle $f.low - $f.high -padx 2 -pady 2 -sticky w
+    grid $f.coordtitle $f.coordbutton -padx 2 -pady 2 -sticky w
+    grid $f.colortitle $f.colorbutton -padx 2 -pady 2 -sticky w
+    grid $f.marktitle $f.markbutton -padx 2 -pady 2 -sticky w
+    grid $f.rangetitle $f.low $f.high -padx 2 -pady 2 -sticky w
 
     # Buttons
     set f [ttk::frame $w.buttons]
diff --git a/ds9/parsers/masklex.fcl b/ds9/parsers/masklex.fcl
index cafe4b6..22817ef 100644
--- a/ds9/parsers/masklex.fcl
+++ b/ds9/parsers/masklex.fcl
@@ -11,6 +11,8 @@ close	    {return $CLOSE_}
 clear	    {return $CLEAR_}
 color	    {return $COLOR_}
 mark	    {return $MARK_}
+nan	    {return $NAN_}
+nonnan	    {return $NONNAN_}
 nonzero	    {return $NONZERO_}
 open	    {return $OPEN_}
 range	    {return $RANGE_}
diff --git a/ds9/parsers/maskparser.tac b/ds9/parsers/maskparser.tac
index df578d4..3c777a7 100644
--- a/ds9/parsers/maskparser.tac
+++ b/ds9/parsers/maskparser.tac
@@ -13,6 +13,8 @@
 %token CLOSE_
 %token COLOR_
 %token MARK_
+%token NAN_
+%token NONNAN_
 %token NONZERO_
 %token OPEN_
 %token RANGE_
@@ -45,6 +47,8 @@ mask : {global parse; set parse(result) mask}
 
 mark : ZERO_ {set _ zero}
  | NONZERO_ {set _ nonzero}
+ | NAN_ {set _ nan}
+ | NONNAN_ {set _ nonnan}
  | RANGE_ {set _ range}
  ;