Have you all solve importing Z point from dxf to QGIS? I have read all the answer about importing dxf to QGIS, but I still not understand yet.  Does anyone have a video link (youtube or another) that show me step by step to export dxf with Z point to QGIS?
Importing 3D DXF file into QGIS with z information as attribute value? I have a dxf file of 3d contours. after import it does have only  layer,x,y attribute and doesn't have Z attribute.  How can I provide Z attribute to create a TIN file?
We can easily find out if the vectors are dependent or not by finding determinant of matrices formed from the vectors. But if the matrix is not a square matrix, we cannot find the determinant. Then how do we know if the vectors are linearly independent? Show that $\tan{(\pi/7)} \tan{(2\pi/7)}\tan{(3\pi/7)}=\sqrt{7}$ From this , I now understand the gradient to be the directional derivative that returns the steepest slope at a point. However, reading my textbooks, they all say that the gradient is normal to the tangent plane. In the above SE question, the gradient sounds like it should be parallel to a direction in the $xy$ plane, not actually up on the surface.   My question is therefore do I have a misunderstanding of the tangent plane, gradient or directional derivative?   In addition, I question how the gradient always passes through the origin or the $xy$ plane? If for instance in the graphic, the gradient had been another direction (say horizontal), then it wouldn't pass through the origin! In addition, the gradient of other points in the graphic would satisfy this example. Many thanks! Primitive of holomorphic Function $\frac{1}{z}$ on an Annulus. Given an Annulus with $A(0,r,R)$ show by considering Cauchy's Theorem for primitives that there is no holomorphic function with $f'(z)=\dfrac{1}{z}$.   I am struggling to picture this since but it seems like there are issues because $f(z)=\log z$ isn't well defined in the same range as $\dfrac{1}{z}$.  Am I looking to show that $\int_Ag(z)dz = 0$ where $g(z) = \dfrac{1}{z}$? Boot error > no such device: grub rescue After an installation of Ubuntu 12.04, erasing an old partition with Ubuntu 10.10, I can't get grub to load. I can't access my Windows 7 partition either  I get the message:  &gt; error: no such device: 58ABF29C...   grub rescue&gt;   I suppose my master boot record got erased/corrupted. How can I check and fix this? I was editing my mesh and I wanted to only see a part of my mesh, so I pressed alt+B to only show a selected area. However, I did ctrl+B and created a red rectangle on my screen (I don't know what it does). Does anybody know how to get it off? Why did Obi-Wan allow Leia to get adopted by such a high profile figure? I know that Leia is a princess because she was adopted by the Queen of Alderaan, but why would Obi-Wan allow this? Wasn't the original plan of Obi-Wan and Yoda to hide the Skywalkers from Palpatine? Luke was placed into a very low-profile position, being the child of two farmers on a backwater planet. However, Leia occupies a very important political position.  Is there any reason why Obi-Wan would do this if he was trying to hide her? I noticed something strange recently when trying to use rounded corners in pgfplots: it totally ruins the plot. See below without rounded corners:    and then with rounded corners:    Here is a minimal example:  \documentclass{standalone} \usepackage{pgfplots} \pgfplotsset{compat=newest}  \begin{document}  \begin{tikzpicture}[scale=0.8,trim axis left, trim axis right] \tikzset{every mark/.append style={scale=0.6}} \pgfplotsset{legend style={font=\footnotesize}}  \begin{axis}[   grid=both,             rounded corners,             ]     \addplot[samples=100,color=blue,very thick,smooth,domain=-10:10] {cos(x^(3))}; \end{axis} \end{tikzpicture}  \end{document}   Thanks in advance for your ideas ! Illustrator CS5 brick pattern with perspective I created a curving arrow shape that starts wide at the bottom and thins out near the top where the point is. I also created a brick pattern swatch but when I apply it to the shape it appears like the pattern is overlaid instead of like a real road where the bricks follow the shape and narrows near the most distant point. How can I apply a perspective to the brick pattern without looking like I used a clipping mask?  Here is a link to what I achieved with a clipping mask - not what I want though. I need the bricks to look like they are inlaid just like in real life. How to solve $\lim_{x \rightarrow 0} {\frac{(1+x)^a-1}{x}}$? How to solve this limit without using L'Hospital rule?  $$\lim_{x \rightarrow 0}{\frac{(1+x)^a-1}{x}}$$ Division algorithm for polynomials in R[x], where R is a commutative ring with unity. Is there a division algorithm for polynomials in R[x], where R is a commutative ring with unity?    All the algebra books I read mention division algorithm for polynomials in F[x], where F is a field. Since the leading coefficient of a non zero polynomial in R[x] is not necessarily invertible, I find it difficult to proceed the same way we do for polynomials in F[x].  Can I get some help? I want to filter a java.util.Collection based on a predicate. Update statement with inner join on Oracle I zoomed in / out of one of my UI panels and I can't figure out how to zoom back out/ in to get it normal size.   How can I reset the zoom level of UI panels? Difference between "I'm home" vs "I'm at home" What's the difference between these two sentences? And which one's grammatically correct? Multiple bibliographies (reference lists) using embedded bibliography database I would like to have multiple bibliographies (reference lists) as described in   ().   However, I'd like to use with a single .tex file, which would contain the bibliography database embedded, as in  ...   Now, I want to use letter documentclass, for which the bibliography needs to be defined ()   So what I end up is with this example (code below, compiled with just pdflatex, no bibtex(which I'd like to avoid in this case)):     ... obviously, something works (multibib recognized primary and secondary cites, assigning them number "1" as start) -- however I don't get two, separate primary and secondary list of references; would that be possible in this context? (doesn't have to be with multibib, but I'd like to avoid a separate .bib file and a bibtex call)  EDIT: I'd also like separate cite keys (i.e. rendered as [a1] and [b1]; not yet sure if multibib can do that; edit: no it cant,  says "You can also edit the .bbl files created by BibTEX and add 'a', 'b',. . . to the labels, but your changes will be overwritten by subsequent BibTEX runs." and recommends \cite[a]{key}) - how possible would that be?  &nbsp;  The code is this:   \documentclass{letter}  % Environment thebibliography undefined when using letter: http://www.latex-community.org/forum/viewtopic.php?f=4&amp;t=3359 \makeatletter \setlength \labelsep {.5em} \newcommand\newblock{\hskip   .11em\@plus.33em\@minus.07em} \let\@openbib@code\@empty \newcommand\refname{References} \newcommand\section{\@startsection   {section}{1}{\z@}%   {-3.5ex \@plus -1ex \@minus -.2ex}%   {2.3ex \@plus.2ex}%   {\normalfont\Large\bfseries}} \newenvironment{thebibliography}[1] {\section*{\refname}%   \@mkboth{\MakeUppercase\refname}{\MakeUppercase\refname}%   \list{\@biblabel{\@arabic\c@enumiv}}%   {\settowidth\labelwidth{\@biblabel{#1}}%     \leftmargin\labelwidth \advance\leftmargin\labelsep \@openbib@code     \usecounter{enumiv}%     \let\p@enumiv\@empty \renewcommand\theenumiv{\@arabic\c@enumiv}}%   \sloppy \clubpenalty4000 \@clubpenalty \clubpenalty   \widowpenalty4000%   \sfcode`\.\@m} {\def\@noitemerr {\@latex@warning{Empty       `thebibliography' environment}}%       \endlist} \makeatother  \usepackage{multibib} \newcites{pri}{Primary sources} \newcites{sec}{Secondary sources}  \begin{document}   \begin{letter}{Addressee} Blah, blah - content...  Primary cite: \citepri{lamport94} ...  Secondary cite: \citesec{lamport94} ...   \begin{thebibliography}{9}  \bibitem{lamport94}   Leslie Lamport,   \emph{\LaTeX: A Document Preparation System}.   Addison Wesley, Massachusetts,   2nd Edition,   1994.  \bibitem{lamport95}   Leslie Lamport,   \emph{\LaTeX: A Document Preparation System}.   Addison Wesley, Massachusetts,   2nd Edition,   1995.  \end{thebibliography}  \end{letter}   \end{document} I have a char in c#:  char foo = '2';   Now I want to get the 2 into an int.  I find that Convert.ToInt32 returns the actual decimal value of the char and not the number 2.  The following will work:  int bar = Convert.ToInt32(new string(foo, 1));   int.parse only works on strings as well.    Is there no native function in C# to go from a char to int without making it a string?  I know this is trivial but it just seems odd that there's nothing native to directly make the conversion. Is Java's default value for Boolean 'true'? How to change desktop background from command line in Unity? I have a script that updates my desktop background every day with the NASA APOD. Since upgrading to 11.10, that script stopped working, presumably because I'm using gconftool-2 to actually update the desktop background. Is there a new way to do this under Unity? I used to have an icon on the Windows Vista taskbar showing the battery amount remaining (laptop). It has mysteriously vanished.  How can I get it back?  I followed the Windows  (see How can I hide the battery icon in the notification area? - hoping to reverse the instructions) but the Power checkbox on the Notification Area tab was greyed out and could not be checked or unchecked (it is currently unchecked).