Is there a way to add a perpendicular line to the end node of each polyline? Something like this:
I have some lines. I want to draw perpendicular lines at the start and end of the lines, on both sides of the lines.  Can somebody help me in Python?  I am using ArcGIS.
How to set security options for a PDF using pdflatex Was Grand Moff Tarkin under Darth Vader's control? In A New Hope, we see Grand Moff Tarkin ordering Darth Vader around. Also, it was . It's uncertain whether he knew .  But considering that Darth Vader was a Sith Lord, and a Jedi before that, are we entirely sure he wasn't secretly controlling Tarkin through a Jedi Sith mind trick? Do lenses have focal planes or focal spheres/ellipsoids? Silencing "Your disk is almost full" notification After upgrading to macOS Sierra, I'm getting the notification that "Your disk is almost full. Save space by optimizing storage.":    The options appear to be to store my files in iCloud, automatically delete files, or manually delete files:    My problem/irritation is that I have 80GB free of my 440GB volume.  The question: is there a way to silence this notification in a (semi-)permanent fashion, or to change the threshold it uses for the notification? How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar" In bash, calling foo would display any output from that command on the stdout.  Calling foo &gt; output would redirect any output from that command to the file specified (in this case 'output').  Is there a way to redirect output to a file and have it display on stdout? I am sure there is something wrong i am doing but i just want someone to point it to me.  Why can't we say that $e^{\frac {\pi i}{3}} = \left(e^{\pi i}\right)^{\frac {1}{3}} = (-1)^{\frac {1}{3}} = -1$ Why do we have to calculate it by the formula as it is (which produces different value)  Another question is why can't we say that $ (-1)^{\frac {1}{2}} = \left(\left (-1\right)^{2}\right)^{\frac {1}{4}} = 1^{\frac {1}{4}} = 1$  Again i have to say that i know this is all wrong i just want to know why it is wrong How to do a generalized linear model with multiple dependent variables in R? I have six dependent variables (count data) and several independent variables, I see that in a MMR the script goes like this:  my.model &lt;- lm(cbind(DV1,DV2,DV3,DV4,DV5,DV6) ~ IV1 + IV2 + ... + IVn)   But, since my data are counts, I want to use a generalized linear model and I tried this:  my.model &lt;- glm(cbind(DV1,DV2,DV3,DV4,DV5,DV6) ~ IV1 + IV2 + ... + IVn, family="poisson")   And appears this error message:  Error in glm.fit(x = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  :    (subscript) logical subscript too long`   Can anyone explain me this error message or a way to solve my problem? Book about mages who can harvest magical energy from the environment What are these circular splotches on my negatives? How are echo and print different in PHP? Possible Duplicate:          Is there any major and fundamental difference between these two functions in PHP? Routing sound from different cards to a single output I have a setup where I am monitoring for silence on an incoming stream on 3 different audio cards.  When I detect silence on the master I switch to the secondary, and if I detect silence there I switch to the last card.  The way I have it set up I load/unload the loopback module for each card depending on who's the active card.  This has the inconvenience that I need a 3-to-1 minijack cable to be able to maintain the stream.  Can I load the loopback module and point the output to a single card (independently of the input card)?  How can I route the audio from any input to a single output? Understanding how references and labels work I'm trying to understand why I cannot effectively reference figures or equations that I have defined with labels.  For example:  \begin{figure}   \label{fig:area_Treasuries}   \caption{Treasuries as a portion of total financial flows.}   \centering   \includegraphics[width=0.75\textwidth]{graphs/Area_Treasuries.png} \end{figure}  \paragraph{} Figure~\ref{fig:area_Treasuries} presents Treasuries (both flowing into and out of the United States) as a share of total financial flows.  From 1985 to 2010, Treasuries account for, on average, 53.2\% of total financial flows.   With the above code, I get this warning:      LaTeX Warning: Reference `fig:area_Treasuries' on page 37 undefined on   input line 477.   The result is "Figure ?? presents Treasuries..."  Why is this happening?  Related, I don't understand why I can't reference, say, an equation before (I mean physically above in the text) the actual equation.  Isn't this what compiling multiple times and cross references is supposed to take care of? The question asks to compute:   $$\sum_{k=0}^{n-1}\dfrac{\alpha_k}{2-\alpha_k}$$   where $\alpha_0, \alpha_1, \ldots, \alpha_{n-1}$ are the $n$-th roots of unity.   I started off by simplifiyng and got it as:  $$=-n+2\left(\sum_{k=0}^{n-1} \dfrac{1}{2-\alpha_k}\right)$$  Now I was stuck. I can rationalise the denominator, but we know $\alpha_k$ has both real and complex components, so it can't be simplified by rationalising. What else can be done? Extracting matrix rows when one of its elements is part of a list (without a loop) Let users editing a question know if editing it would add it to the reopen queue This is sort of similar to , which was positively received, but was declined for technical reasons. I propose that users who are editing a post that was closed within the last five days be shown a notice on top of the edit form indicating that the post will be added to the reopen queue if edited, and that if one does not plan on editing the post into a state where it can be reopened, one should wait until five days after closure to make the edit. Closed questions are only added to the review queue once per closure by editing, and if a user comes by and makes a minor (yet benign) edit, the diff that reopen reviewers see is just that of the minor edit, and as such they dismiss the task as &quot;Leave Closed&quot;, which prevents it from being added to the queue again by another edit. This deprives the post author (and others interested in seeing the question reopened) of their chance to get the post reopened by editing. While some of these edits may be performed by users using (semi-)automated tools who would thus not see or overlook the warning, this will be a big help because 99%+ of users make edits solely manually and would thus see and possibly respond to such a notice. To help make this request more technically feasible, I propose that it instead only be loaded with the edit form, and that it should only be shown to users who can make binding edits. (Suggested edits occur at the time of approval, and the request to let the reviewers know has already been declined.) Here's an example of what I'm expecting:  This question was recently [closed/marked as duplicate]. This question will be added to a queue for possible reopening if you make this edit. If you are not planning to edit this post into a state where it can be reopened, please wait until [date and time after 70 days] to make your edit. If you are only making edits to the question's tags, please ignore this notice. Is there a universal way to turn Windows 7 Aero desktop, all windows, etc into grayscale? I had an option to do this in Intel video drivers on my old laptop, now I have NVIDIA and don't know how to replicate this effect.   There might be a shader or filter that would cause Aero to render stuff into grayscale, but I was unable to find anything. Or must it be explicitly supported by video driver as a bonus? When is $2^n \pm 1$ a perfect power Is there an easy way of showing that $2^n \pm 1$ is never a perfect power, except for $2^3 + 1 = 3^2 $?  I know that   gives the result directly, but I'm hopefully for a more elementary method.    I can show that it is never a square, except for $2^3 + 1$.  Proof: Cases $n=1, 2, 3$ are easily dealt with. Henceforth, let $n\geq4$.  $2^n -1 \equiv 3 \pmod{4}$ hence is never a square.     If $2^n +1 =x^2$, then $2^n = (x-1)(x+1)$ and both of these are powers of 2. Thus we must have $(x-1) = 2, (x+1) = 4$. This gives the solution of $2^3 + 1 = 3^2$.    Let's now do an odd prime.  Say $2^n +1 = x^p$. Then $2^n = x^p - 1 = (x-1)(x^{p-1}+x^{p-2} + \ldots +1)$, so both terms are powers of 2. We have $ x = 2^m+1$ is odd. But the other term is the sum of $p$ odd numbers, hence is odd. Since this is clearly greater than 1, we get a contradiction.  Say $2^n -1 = x^p$. Then $2^n = x^p + 1 = (x+1)(x^{p-1} - x^{p-2} + \ldots -x +1 )$, so both terms are powers of 2. We have $x = 2^m -1$ is odd. But the other term is the sum of $p$ odd numbers, hence is odd. Since $x^p + 1 \neq x+1$ except for $p=1$, this means that the term is greater than 1. Hence we get a contradiction. What if the answers of a historical locked question become obsolete? Book ID: Astronauts and Lab Students can create portals through space