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<p class="MsoNormal"><span lang="EN-US">Hello, list. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I am confused about the result I get from the Proj4 inverse projection of Lambert Azimuthal Equal Area,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">when the original projected input point is outside the valid circle.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I thought that in cases like these, the result point should have coordinates that are
</span><span lang="EN-US" style="font-family:"Courier New"">HUGE_VAL</span><span lang="EN-US"> , that is,
</span><span lang="EN-US" style="font-family:"Courier New";color:black">1e+300</span><span lang="EN-US">.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">There seems to be code in </span><span lang="EN-US" style="font-family:"Courier New"">pj_inv.c</span><span lang="EN-US"> that checks error conditions and sets coordinates to
</span><span lang="EN-US" style="font-family:"Courier New"">HUGE_VAL</span><span lang="EN-US">, but these<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">checks aren’t triggered in my example.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Instead, my debugger says that I get a point with coordinates
</span><span lang="EN-US" style="font-family:"Courier New"">–nan(ind)</span><span lang="EN-US">.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I suppose that is an <i>Indefinite NaN</i>. I am not too familiar with the various flavours of NaN, but it’s certainly different from
</span><span lang="EN-US" style="font-family:"Courier New";color:black">1e+300</span><span lang="EN-US">.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Here is a concrete example that I have run in the console application, using Proj 4.9.3 and EPSG:3035 which is ETRS89 / LAEA Europe:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">C:\> proj -I +init=epsg:3035<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">4321000 3210000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">10dE 52dN<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">16350000 -1090000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">-2147483648d-2147483648'-1.#IO"E -2147483648d-2147483648'-1.#IO"N<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I think I remember that invalid coordinates are usually written as asterisks by the console application.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Avoiding the default DMS formatting of the output, I get the following instead:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">C:\>proj -I +init=epsg:3035 -f "%.5f"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">4321000 3210000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">10.00000 52.00000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">16350000 -1090000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">-1.#IND0 -1.#IND0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">So my question is, is this a kind of bug in the implementation of inverse LAEA, or is it to be expected that invalid coordinates<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">can be represented by either</span><span lang="EN-US" style="font-family:"Courier New""> HUGE_VAL
</span><span lang="EN-US">or</span><span lang="EN-US" style="font-family:"Courier New""> NaN
</span><span lang="EN-US">depending on the projection?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Best regards, <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal">Mikael Rittri<o:p></o:p></p>
<p class="MsoNormal">Carmenta<o:p></o:p></p>
<p class="MsoNormal">Sweden<o:p></o:p></p>
<p class="MsoNormal">http://www.carmenta.com<o:p></o:p></p>
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