<div dir="ltr"><div class="gmail_default" style="color:#274e13">Hello Nikos,</div><div class="gmail_extra"><br><div class="gmail_quote">2013/11/27 Nikos Alexandris <span dir="ltr"><<a href="mailto:nik@nikosalexandris.net" target="_blank">nik@nikosalexandris.net</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">Cesar Augusto Ramírez Franco wrote:<br>
<br>
> Hello everyone,<br>
<br>
</div>Hello,<br>
<div class="im"><br>
<br>
> I've been trying to do a supervised classification from landsat8 imagery<br>
> using i.class and then i.maxlik, but I'm getting an error when running<br>
> i.maxlik saying it can't read the signature file.<br>
<br>
</div>Just to double-check: verify that your "classes" don't overlay any NULL cells.<br>
It might be completely irrelevant, I have, though, blurry memories of this<br>
being a blocker actually (with i.smap at least).</blockquote><div><br></div><div><div class="gmail_default" style="color:rgb(39,78,19)">There are no NULL cells on my classes, neither on my Landsat 8 images or the Landsat 7 in the North Carolina dataset</div>
</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">
> I tested my procedure on the NC sample dataset and I'm getting the same<br>
> error, I'm using Grass 6.4.2 on Debian Wheezy, installed from the debian<br>
> repo. Here's the command set:<br>
<br>
> #Display RGB enhanced map<br>
> i.landsat.rgb blue=lsat7_2000_10 green=lsat7_2000_20 red=lsat7_2000_30<br>
> d.rgb blue=lsat7_2000_10 green=lsat7_2000_20 red=lsat7_2000_30<br>
<br>
> #"Real color" map<br>
> r.composite red=lsat7_2000_30 green=lsat7_2000_20 blue=lsat7_2000_10<br>
> output=lsat7_2000_RGB<br>
<br>
> #Group images to process<br>
> i.group group=lsat7_2000_RGB subgroup=lsat7_2000_RGB<br>
> input=lsat7_2000_10,lsat7_2000_20,lsat7_2000_30<br>
<br>
> #Unsupervised classification<br>
> i.cluster group=lsat7_2000_RGB subgroup=lsat7_2000_RGB sigfile=clustlsat7<br>
> classes=20 report=rep_clust_lsat7.txt<br>
<br>
</div>(I have never tried to feed a group that uses a single composite. I'll try it<br>
out.)<br></blockquote><div><br></div><div><div class="gmail_default" style="color:rgb(39,78,19)">The composite is for the supervised clasification, the group and subgroup are made with the 3 RGB bands (1,2,3 in Landsat7 or 2,3,4 in Landsat8)</div>
<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">
> i.maxlik group=lsat7_2000_RGB subgroup=lsat7_2000_RGB sigfile=clustlsat7<br>
> class=lsat7_classes reject=lsat7_classes_rej<br>
<br>
</div>Does the unsupervised classification work? i.cluster requires at least two<br>
input raster maps. And, honestly, I have never tried it the way you did, i.e.<br>
by using a composite map. Also, r.composite will use by default "32 levels"<br>
whicih means that you loose important info for the subsequent classification,<br>
if I am not wrong.</blockquote><div> </div><div><div class="gmail_default" style="color:rgb(39,78,19)">The supervised classification does work, i.cluster generates a signature file and i.maxlik success to create the classes raster map</div>
</div><div class="gmail_default" style="color:rgb(39,78,19)"><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">
> #Supervised classification<br>
> i.class map=lsat7_2000_RGB group=lsat7_2000_RGB subgroup=lsat7_2000_RGB<br>
> outsig=classlsat7<br>
> i.maxlik group=lsat7_2000_RGB subgroup=lsat7_2000_RGB sigfile=classlsat7<br>
> class=lsat7_class_sup<br>
<br>
> Here I get the error in which i.maxlik can't read the signature file<br>
> created by i.class (classlsat7) but read the one created by i.cluster<br>
> flawlessly<br>
><br>
> This is what I'm selecting on the i.class monitor, I named it vegetation:<br>
> [image: Imagen integrada 1]<br>
<br>
</div>Only on class? Can you try with more please?<br></blockquote><div><br></div><div class="gmail_default" style="color:rgb(39,78,19)">Yes, the error I'm getting is only with the i.class module</div><div class="gmail_default" style="color:rgb(39,78,19)">
<br></div><div class="gmail_default" style="color:rgb(39,78,19)">I'm doing some tests creating a test vector with my classes as areas, then converting it to raster with v.to.rast, and then using that raster to generate statistics for i.smap with i.gensigset</div>
<div class="gmail_default" style="color:rgb(39,78,19)"><br></div><div class="gmail_default" style="color:rgb(39,78,19)">I don't know if I'm not using the i.class module the right way or if it's broken</div><div class="gmail_default" style="color:rgb(39,78,19)">
<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">
> And the contents of the classlsat7 signature file are the following:<br>
><br>
> #<br>
><br>
> #vegetation<br>
><br>
> 166<br>
> <br>
> Am I doing something wrong or is it some kind of bug?<br>
<br>
</div>Greets, Nikos<br>
</blockquote></div><br><div class="gmail_default" style="color:rgb(39,78,19)">Thank you very much</div><div><br></div>-- <br><div dir="ltr"><div style="text-align:right"><b style="color:rgb(39,78,19)">César Augusto Ramírez Franco</b></div>
<font color="#274e13"><div style="text-align:right">Laboratorio de Sistemas Complejos Naturales</div><span style="font-family:Arial;vertical-align:baseline;white-space:pre-wrap"><div style="text-align:right">Escuela de Geociencias</div>
</span></font><div><div style="text-align:right"><span style="white-space:pre-wrap;font-family:Arial;color:rgb(39,78,19)">Facultad de Ciencias</span></div><font color="#274e13"><div style="text-align:right">Universidad Nacional de Colombia - Sede Medellín</div>
</font></div><font color="#274e13"><div style="text-align:right">Teléfono: (57-4) 430 9369 -<font face="arial, helvetica, sans-serif"> 301 389 5607</font></div></font></div>
</div></div>