Image recognition between Improved vs Raw Land for city parcels from Aerial with QGIS?
What is Change Detection and performing such analysis with open source tools?
If I press the "include alpha-button" in the Mix-Color-Node, I get white borders. Otherwise i've got a perfect alpha but no blue background. Titles of articles I'm about to cite contain upper case letters and when using BibTeX it converts them to lower case ones. This happens only in the title and only the first letter conserves its case. For example, when I cite an article about HF, the reader won't know if it is about Hafnium (Hf) or fluorine acid (HF).  I know that I can fix it manually in the .bbl file but I would like to avoid it, or fix it automatically. New top bar quick reference guide / Where has the link to  gone? Name of component on output side cable of a DC power adapter? This is an exercise from textbook Analysis I by Amann/Escher.  Let $G$ be a group and $X$ a nonempty set. Then $G$ acts (from the left) on $X$ if there is a function $$G \times X \rightarrow X, \quad(g, x) \mapsto g \cdot x$$ such that: GA1: $e \cdot x=x$ for all $x \in X$. GA2: $g \cdot(h \cdot x)=(g h) \cdot x$ for all $g, h \in G$ and $x \in X$. Let $\mathrm{S}_{m}$ be the set of all permutations of $\{1,2,\cdots,m\}$. Then $(\mathrm{S}_{m},\circ)$ is a group where $\circ$ is function composition operation. Show that $$\mathrm{S}_{m} \times \mathbb{N}^{m} \rightarrow \mathbb{N}^{m}, \quad(\sigma, \alpha) \mapsto \sigma \cdot \alpha := \left(\alpha_{\sigma(1)}, \ldots, \alpha_{\sigma(m)}\right)$$ defines an action of $\mathrm{S}_{m}$ on $\mathbb{N}^{m}$.  I am stuck at proving the GA2, i.e. $\pi \cdot (\sigma \cdot \alpha) = (\pi \circ \sigma) \cdot \alpha$.  My attempt: Clearly, $\operatorname{id}$ is the identity element of $\mathrm{S}_{m}$ and $\sigma \cdot \alpha = \alpha \circ \sigma$. Because $\operatorname{id} \cdot \alpha = \left(\alpha_{\operatorname{id}(1)}, \ldots, \alpha_{\operatorname{id}(m)}\right) = \left(\alpha_1,\cdots,\alpha_m\right) = \alpha$, GA1 follows. For $\pi,\sigma \in \mathrm{S}_{m}$ and $\alpha \in \mathbb{N}^{m}$, we have $$\pi \cdot (\sigma \cdot \alpha) = (\alpha \circ \sigma) \circ \pi = \alpha \circ (\sigma \circ \pi) = (\sigma \circ \pi) \cdot \alpha$$  It is clear that $\sigma \circ \pi = \pi \circ \sigma$ if and only if $(\mathrm{S}_{m},\circ)$ is Abelian, which is not true in general. Please help me figure out where I am wrong! C++ namespace and include Why do we need both using namespace and include directives in C++ programs?  For example,   #include &lt;iostream&gt;  using namespace std;  int main() {  cout &lt;&lt; "Hello world"; }   Why is it not enough to just have #include &lt;iostream&gt; or just have using namespace std and get rid of the other?  (I am thinking of an analogy with Java, where import java.net.* will import everything from java.net, you don't need to do anything else.) How do I update Ubuntu manually? I wanted to update Ubuntu manually, because I used CDMA USB modem and connected using wvdial, but it won't able to update Ubuntu via Update Manager, because my Ubuntu won't showing "Connected" message via network-manager.  Can I update Ubuntu manually? Am I should download separate files, or use terminal instead? Rationale behind pronunciation of "subtle" My textbook explains the proof, which I don't understand:  "Consider two bases $v_1...v_p$ and $w_1...w_q$ of V. Since the vectors $v$ are linearly independent and the vectors $w$ span V..."  How exactly does $w$ span V?   The book then says the same for vectors $v$, that $v$ spans V and hence $p=q$, but I don't really understand how you can assume that given two sets of vectors that are basis, one set must span V. How to chat to all I very rarely see chats too all and don't know how to do it myself. Normally it's SHIFT + ENTER The following hotkeys have been tried: - SHIFT + ENTER - CTRL + ENTER - ALT + ENTER How would you count occurrences of a string (actually a char) within a string? I am doing something where I realised I wanted to count how many /s I could find in a string, and then it struck me, that there were several ways to do it, but couldn't decide on what the best (or easiest) was.  At the moment I'm going with something like:  string source = "/once/upon/a/time/"; int count = source.Length - source.Replace("/", "").Length;   But I don't like it at all, any takers?  I don't really want to dig out RegEx for this, do I?  I know my string is going to have the term I'm searching for, so you can assume that...  Of course for strings where length > 1,  string haystack = "/once/upon/a/time"; string needle = "/"; int needleCount = ( haystack.Length - haystack.Replace(needle,"").Length ) / needle.Length; What is the procedure for taking down Titans? How do I remove an alias? I want to remove gs alias from my PC. When I type gs it will open GhostScript. But I checked everywhere in the home directory .alias  .bash_aliases .bashrc  I also overwrite the gs with my custom alias.   I can't remove it. And I also type alias in terminal, in the list I couldn't find it.   Please I want to remove it... Conveying "under the radar" in a less colloquial way What is the most "pythonic" way to iterate over a list in chunks? What is the "Bootable flag" option when installing a distro? Is the "bootable flag" needed in today's distributions? If not, then why is it still in the installers? What is it exactly? Is clockwise or counter-clockwise rotated text easier to read? When rotating text with css, should it be rotated clockwise or counter-clockwise?  Is one more readable than the other?  Counter Clockwise:   &nbsp;&nbsp;&nbsp;&nbsp;&mdash;&nbsp;&nbsp;&nbsp; Clockwise: Will Determinism be ever possible? Best practice when analysing pre-post treatment-control designs Imagine the following common design:   100 participants are randomly allocated to either a treatment or a control group the dependent variable is numeric and measured pre- and post- treatment   Three obvious options for analysing such data are:   Test the group by time interaction effect in mixed ANOVA Do an ANCOVA with condition as the IV and the pre- measure as the covariate and post measure as the DV Do a t-test with condition as the IV and pre-post change scores as the DV   Question:    What is the best way to analyse such data?  Are there reasons to prefer one approach over another? Prove that $\sum^{n}_{r=0}(-1)^r\cdot \large\frac{\binom{n}{r}}{\binom{r+3}{r}} = \frac{3!}{2(n+3)}$