<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style></head><body lang=ES-MX link=blue vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Hi,</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I added a vector layer to QGIS 3.36.0 by importing a dxf file (it contains two polygons). I want to calculate the differentce in área of the polygons (considering the topography of a DEM file visualized in hillshade). So, I opened the attribute table, created a calculated field (ANRio) with the $area expression, but I get a NULL value. I see that my attribute table has NULL values for Paper Space and Line Type (I do not know if that might be the problem). I am probably not importing the polygons properly. I also tried importing as shape file using “anotherDXFimport” plugin but still I get NULL values in the area calculated field.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I would appreciate your help.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Jose</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Imported polygons</p><p class=MsoNormal><img width=624 height=351 style='width:6.5in;height:3.6562in' id="_x0000_i1026" src="cid:image003.png@01DA7D2E.988128E0" alt="Mapa
Descripción generada automáticamente"></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Attribute tables</p><p class=MsoNormal><img width=624 height=351 style='width:6.5in;height:3.6562in' id="Imagen_x0020_1" src="cid:image005.png@01DA7D2E.988128E0" alt="Interfaz de usuario gráfica, Aplicación
Descripción generada automáticamente"></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sent from <a href="https://go.microsoft.com/fwlink/?LinkId=550986">Mail</a> for Windows</p><p class=MsoNormal><o:p> </o:p></p></div></body></html>