Are there any free online GIS courses based around using QGIS?
Seeking QGIS tutorials and web resources?
Is it possible to use multiple here-docs in bash? Can one use multiple here-docs to provide input to a command in bash?  $ cat &lt;&lt;&lt;foo &lt;&lt;&lt;bar bar $ cat &lt;&lt;EOF1 &lt;&lt;EOF2 &gt; foo &gt; EOF1 &gt; bar &gt; EOF2 bar   Obviously, in both cases, the second here-doc is used as stdin, and replaces the first reference. Is the solution to use echos instead?  $ cat &lt;(echo -n foo) &lt;(echo bar) foobar   Also, for some reason, using a combination didn't work for me. Why would that be?  $ cat &lt;&lt;&lt;foo &lt;(echo bar) bar $ cat &lt;(echo -n foo) &lt;&lt;&lt;bar foo Optimal tiling of polygon using ArcGIS Desktop? I am trying to tile a polygon with a minimal number of fixed sized squares.  Currently I am creating a fishnet over my polygon then spatially joining the squares that intersect the polygon. This is not optimal.  Also note the squares can be shifted vertically/horizontally but not rotated.  My end goal: The polygon represents a clipped image and I want a tiling of the clipped image. Where each tile is 300px by 300px. Some overlap is fine if that makes the problem easier.  Current    Manually optimized    Are there any tools or algorithms that would help with this? I am proficient with Python and ArcMap.  The polygon was created from line features so I also have access to those segments. Maybe that would will help for generating the squares.  The entire polygon must be covered. How did Dumbledore gain the loyalty of Fawkes? How did Dumbledore find Fawkes. Did Dumbledore have Fawkes even when working as a Transfiguration teacher or acquired it after having Headmaster position. They both have a very strong bond between them. When did Dumbledore gain this. Update: Dumbledore says that Ollivander wrote to him when Harry's wand was purchased; if Dumbledore did not have Fawkes before 1938, he would not know about the two feathers being in the wands, so Fawkes and Dumbledore must have met and bonded before 1938  “My wand's feather came from Fawkes?” Harry said, amazed. &quot;Yes,” said Dumbledore. “Mr. Ollivander wrote to tell me you had bought the second wand, the moment you left his shop four years ago.” -Harry Potter and the Goblet Of Fire, Chapter 36-The Parting Of the Ways.  Update 2: JKR says that Dumbledore was the only owner of Fawkes. So it is to be believed that Fawkes was a wild Phoenix before its bonding with Dumbledore.  Peter Humphreys for BBC Newsround: Who did Fawkes previously belong to and will he play a vital role in the next book? JK Rowling: I am not going to answer about the role in the next books, which probably gives you a big clue, and he has never been owned by anyone but Dumbledore. You will notice that when Harry goes back in the Pensieve in this book, Fawkes is never there, and ­­ no, I am sorry, not in this book, I take that back. When Harry has previously seen the study with a different headmaster he saw it with Dippet and Fawkes was not there then. Fawkes is Dumbledore's possession, not a Hogwarts possession. How to convert mediawiki syntax to latex? This is the announcement post of the Stack Exchange Data Explorer. Its answers were meant to iron out the initial glitches 6 to 8 years ago.  If you have found a bug or need support  today with any of SEDEs features, please ask a new question and tag it with   What does it do? Allows you to run arbitrary SQL queries on the data dumps, and share those queries with your friends. Technical details It is hosted on the Stack Exchange infrastructure , the database is hosted on the same SQL Server version all other sites are hosted on. You can use most of the TSQL commands, even create temporary objects (but not User Defined Functions). The controls used are jQuery based, the grid is  . All query results are cached, so sharing a link to a query will not result in the server going in to a tailspin. The query edit control is a slightly modified  control, I also am considering bespin cause the inter iframe communication is nasty complicated. It gives up nice syntax highlighting for queries. Parameters There is support for parameterized queries, to get it to work name your params like ##this##. For example have a . Query name and description A query can have a name and description, to name it lead with a comment, to describe it continue commenting, for example: -- This is my query name  -- This is my description -- I can span multiple lines  SELECT 1  Anonymous users can initially name a query, but can not change the names of any existing queries. Tutorial There's a  which helps you getting started in writing your own SQL queries. Logging in You can use your openid provider to log in, at the moment once logged in we will track the list of queries you execute (giving you basic history support) Also if there are any params named UserId they will be populated automatically if your EmailHash matches the one on the site being queried. Magic columns If you alias an id column with as [Post Link] it will automatically create a link in the result set to the parent site. Similarly if you alias an id column with as [User Link] it will display a link to the user page. select top 10 * from Posts will show you how tags are done. (Magic columns for images is planned) example (most controversial posts:  ) So what are you waiting for, check it out at  Any feedback would be greatly appreciated. I hope to have the login section working fairly soon and allow voting on the best queries and commenting. Featured Queries At the moment, admins have permission to feature interesting queries on this page , I am looking for better ways to manage the huge query list that is building up. I was doing graph theory homework. I was counting the spaning trees of graph G. Such that G is two complete graphs on n vertices connected by two edges. I got to this expression: $$2n^{2\left(n-2\right)}+2\left(n^{\left(n-2\right)}\sum_{i=0}^{n-2}\binom{n-2}{i}\left(1+i\right)^{\left(i-1\right)}\left(n-i-1\right)^{\left(n-i-3\right)}\right)$$ I know that this expression gives the correct result, however, I was told by my teacher that it is possible to express that number in closed form e.g. without the summation. However, I have yet to find a solution. You can start fire by focusing the sunlight using the magnifying glass.   I searched the web whether you can do the same using moonlight. And found  and  - the first two in Google search results.  What I found is the thermodynamics argument: you cannot heat anything to a higher temperature using black body radiation than the black body itself, and Moon isn't hot enough.  It may be true, but my gut feelings protest... The larger your aperture is, the more light you collect, also you have better focus because the airy disk is smaller. So if you have a really huge lens with a really short focus (to keep Moon's picture small), or in the extreme case you build a Dyson-sphere around the Moon (letting a small hole to the let the sunlight enter), and focusing all reflected light into a point it should be more than enough to ingnite a piece of paper isn't it?   I'm confused. So can you start fires using the Moon? Let $G$ be a finite group of order $n\ge2$. Which of the following statements are true? a. There always exists an injective homomorphism from $G$ into $S_n$. b. There always exists an injective homomorphism from $G$ into $S_m$ for some $m\lt n$. c. There always exists an injective homomorphism from $G$ into $GL_n(R)$.  I think b. is right (don't know how to prove though). I also think that c. is false. But not sure. Prove the divisibility test by $7,11,13$ for numbers more than six digits Let $a,b,c>0$ such that $a+b+c=3$, find max/min of $\frac1{a^2+1}+\frac1{b^2+1}+\frac1{c^2+1}$ Let $a,b,c&gt;0$ be real numbers such that $a+b+c=3$, find the maximum and minimum of:   $$\frac1{a^2+1}+\frac1{b^2+1}+\frac1{c^2+1}$$   I've tried using AM-GM-HM, but I can't find the maximum or the minimum.  Using intuition, substituting $a=b=c=1$ should give us one of the optimums, but I cannot prove that it is the optimum. How resilient is Ubuntu to repeated "power-off" shutdowns? My company is considering the use of Ubuntu as an OS for use on a hardware device.     It would be installed on compact flash drive - apparently this is not standard flash drive but a specific type of memory that is supposed to "cope" with immediate power shutdown (I am not sure how this is achieved but they are supposedly a "high end" card).    The units that would be run using Ubuntu are the type of units that will not be gracefully shutdown - the power cable would be removed and that is that.     Can anybody give me some advice on the potential problems that can occur? Is Ubuntu a good system that can deal with this kind of power outage and reboot successfully on next startup?     I realise that nothing is unbreakable, but is it a commonly used OS for an embedded setup? Is it asking for trouble to use Ubuntu in this kind of environment? What does it mean by 'bringing him gasping to all fours' in Harry potter? Immediately, his insides started writhing as though he'd just swallowed live snakes -- doubled up, he wondered whether he was going to be sick -- then a burning sensation spread rapidly form his stomach to the very ends of his fingers and toes -- next, bringing him gasping to all fours, came to a horrible melting feeling, as the skin all over his body bubbled like hot wax -- and before their eyes, his hands began to grow, the fingers thickened, the knuckles were bulging like bolts -- his shoulders stretched painfully and a prickling on his forehead told him that his hair was creeping down toward his eyebrows -- his robes ripped as his chest expanded like a barrel bursting its hoops -- his feet were agony in shoes four sizes too small      Harry potter and the chamber of secrets   It is the description of the feeling of drinking Polyjuice Potion, which makes someone into a different person, from the point of view of Harry Potter turning into Gregory Goyle.  And I don't understand what 'bring him gasping to all fours' means, especially 'four'. Does four here mean number 4? How to make tr aware of non-ascii(unicode) characters? I'm trying to remove some characters from file(UTF-8). I'm using tr for this purpose:   tr -cs '[[:alpha:][:space:]]' ' ' &lt;testdata.dat    File contains some foreign characters (like "Латвийская" or "àé"). tr doesn't seem to understand them: it treats them as non-alpha and removes too.  I've tried changing some of my locale settings:  LC_CTYPE=C LC_COLLATE=C tr -cs '[[:alpha:][:space:]]' ' ' &lt;testdata.dat LC_CTYPE=ru_RU.UTF-8 LC_COLLATE=C tr -cs '[[:alpha:][:space:]]' ' ' &lt;testdata.dat LC_CTYPE=ru_RU.UTF-8 LC_COLLATE=ru_RU.UTF-8 tr -cs '[[:alpha:][:space:]]' ' ' &lt;testdata.dat   Unfortunately, none of these worked.  How can I make tr understand Unicode? Order of products of elements in a finite Abelian group We want to show that if $a,b\in G$ where $G$ is a finite Abelian group, we have  $\operatorname{LCM}(|a|,|b|) = |ab|$ given that $ab \neq e$.   How I approached this question was by saying let $\operatorname{LCM}(|a|,|b|) = L$. Then if we show that $L$ divides $|ab|$ and $|ab|$ divides $L$ then $|ab| = L$. Showing that $|ab|$ divides $L$ was fine. But then I am having trouble with the second part that is showing $L$ divides $|ab|$. For this, so far I have:  Consider $(ab)^{|ab|} = e = a^{|ab|}b^{|ab|} $  since we know $a \neq b^{-1}$ by assumption then we can conclude that $|a|$ divides $|ab|$ and $|b|$ divides $|ab|$. We know that $L = \frac{|a||b|}{\operatorname{gcd}(|a|,|b|)}$ from here can we conclude that $L$ divides $|ab|$? How to download Ubuntu Server backups automatically? I'm thinking of an investment in a new root server running ubuntu. Due to the fact, that the provider won't have extra backup-space, I need an other solution.  Is it possible to download the server backups automatically when my desktop machine is connected to the internet and in idle state? How do I test if all minecraft players on a server are in a radius? This has got me. I need a command that tells me if all players on a server are in a radius of a command block. If one of them isn't in the radius, the command will be false. Any ideas? Thanks! ID a book about a mirror world and 4th dimension I read a book about 10-15 years ago about a boy and a girl who find a mirror. What made the mirror special was, they were able to enter the reflection and be a part of the reverse image world. They end up going to school and when asked to write something on the board, it ends up being backwards, but to them looks normal.  Later, the two end up in a world with 4 dimensions. With the added dimension they can't see as they normally could. If one moved a certain way the other would see their insides. Eventually a native of that dimension made some type of device that lets them see regularly.  Other than that my memory is blank. If I remember anything else I will be sure to edit it in. My website is javatechig.com and is around 6 months old. I have used All-in-One SEO WordPress plugin for SEO tricks. Definitely after using SEO plugin, my website page view is increased, but still it is not giving one good site-link in Google Search.   I have followed the following steps:   Created sitemap.xml and submitted to Google Webmaster Tools Edited all posts with meta tags Header tags are carefully taken care   I want to make a sitelink similar to the attached image: How do I execute PHP that is stored in a MySQL database? I'm trying to write a page that calls PHP that's stored in a MySQL database. The page that is stored in the MySQL database contains PHP (and HTML) code which I want to run on page load.  How could I go about doing this? Firefox: Downloading files with drag and drop