<div dir="ltr"><div class="gmail_default" style="font-size:small">Just a minor suggestion: if you want transparency, the value to change is the "alpha" value, which is represented by index 3 (indexes 0 through 2 are the RGB values):</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small"><div style="color:rgb(34,34,34);font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><font face="monospace, monospace"><span style="font-variant-ligatures:no-common-ligatures">cmap(<span class="gmail-m_-5391744944018697390gmail-aBn"><span class="gmail-m_-5391744944018697390gmail-aQJ"><span class="gmail-aBn" tabindex="0" style="border-bottom:1px dashed rgb(204,204,204)"><span class="gmail-aQJ" style="top: 2px; z-index: -1;">10:11</span></span></span></span>,3) = 0.0 ; completely transparent</span><br></font></div><div style="color:rgb(34,34,34);font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-variant-ligatures:no-common-ligatures"><div style="color:rgb(34,34,34);font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial;font-size:12.8px;background-color:rgb(255,255,255)"><span style="font-variant-ligatures:no-common-ligatures"><font face="monospace, monospace">cmap(<span class="gmail-m_-5391744944018697390gmail-aBn"><span class="gmail-m_-5391744944018697390gmail-aQJ"><span class="gmail-aBn" tabindex="0" style="border-bottom:1px dashed rgb(204,204,204)"><span class="gmail-aQJ" style="top: 2px; z-index: -1;">10:11</span></span></span></span>,3) = 0.5 ; half transparent</font></span></div></span></div><div style="color:rgb(34,34,34);font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-variant-ligatures:no-common-ligatures"><font face="monospace, monospace">cmap(10:11,3) = 1.0 ; no transparency (the default)</font></span></div><br class="gmail-Apple-interchange-newline">See example newcolor_10.ncl at:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Applications/rgbacolor.shtml#ex10">http://www.ncl.ucar.edu/Applications/rgbacolor.shtml#ex10</a><br></div><div class="gmail_default"><br></div><div class="gmail_default">I think other examples on that page may be useful.</div><div class="gmail_default"><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Apr 10, 2018 at 5:41 PM, Rashed Mahmood <span dir="ltr"><<a href="mailto:rashidcomsis@gmail.com" target="_blank">rashidcomsis@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I think there is typo, replace:<br>From:<br><span style="font-variant-ligatures:no-common-ligatures">cmap(<span class="m_-5391744944018697390gmail-aBn"><span class="m_-5391744944018697390gmail-aQJ">10:11</span></span>,) = 0.0</span><br><br></div>to <span style="font-variant-ligatures:no-common-ligatures">cmap(<span class="m_-5391744944018697390gmail-aBn"><span class="m_-5391744944018697390gmail-aQJ">10:11</span></span>,:) = 0.0</span><br><div><br></div><div>If at later stage you are using "gsn_define_colormap" then it should be:<br><span style="font-variant-ligatures:no-common-ligatures">cmap(<span class="m_-5391744944018697390gmail-aBn"><span class="m_-5391744944018697390gmail-aQJ">10:11</span></span>,0:2) = 0.0</span><br></div><div><br></div><div>Cheers,<br></div><div>Rashed<br></div><div><br><br></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Tue, Apr 10, 2018 at 4:55 PM, Ty Buckingham <span dir="ltr"><<a href="mailto:ty.buckingham@manchester.ac.uk" target="_blank">ty.buckingham@manchester.ac.<wbr>uk</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
<div>
<div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">Hi there,
<div><br>
</div>
<div>Is it possible to change a single color in an already constructed color map to transparent?</div>
<div><br>
</div>
<div>As an example: I wish to use the "hotcold_18lev" color table, but wish to change the white to transparent. I do not have editing permission to the NCARG root hence cannot change the RGBA value directly. Is it possible to change it within the NCL script?</div>
<div><br>
</div>
<div>Initially, I tried this:</div>
<div><br>
</div>
<div>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;background-color:rgb(255,255,255)">
<span style="font-variant-ligatures:no-common-ligatures">cmap = read_colormap_file("hotcold_18<wbr>lev")</span></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;background-color:rgb(255,255,255)">
<span style="font-variant-ligatures:no-common-ligatures">cmap(10:11,) = 0.0 ; makes whites transparent</span></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;background-color:rgb(255,255,255)">
res@cnFillColors = cmap</p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;background-color:rgb(255,255,255)">
<br>
</p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;line-height:normal;background-color:rgb(255,255,255)">
<font size="2">Yet received the error:</font></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;line-height:normal;background-color:rgb(255,255,255)">
<font size="2"><br>
</font></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;background-color:rgb(255,255,255)">
<span style="font-variant-ligatures:no-common-ligatures">fatal:Error in subscript, normal subscripting is being used, make sure named subscripting has not been used</span></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;background-color:rgb(255,255,255)">
<span style="font-variant-ligatures:no-common-ligatures"><br>
</span></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;line-height:normal;background-color:rgb(255,255,255)">
<span style="font-variant-ligatures:no-common-ligatures"><font size="2">which is related to the "cmap(10:11,)" line. </font></span></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;line-height:normal;background-color:rgb(255,255,255)">
<span style="font-variant-ligatures:no-common-ligatures"><font size="2"><br>
</font></span></p>
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;line-height:normal;background-color:rgb(255,255,255)">
<font size="2">Thanks in advance!</font></p><span class="m_-5391744944018697390HOEnZb"><font color="#888888">
<p style="margin-right:0px;margin-left:0px;font-stretch:normal;line-height:normal;background-color:rgb(255,255,255)">
<font size="2">Ty</font></p>
</font></span></div>
</div>
</div>
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