In academic papers, technical reports, and presentations, clear and professional-looking diagrams are crucial. Many authors resort to external drawing programs—Illustrator, Inkscape, Visio—and then import rasterized or vector images into LaTeX. While this approach works, it introduces issues: maintaining consistent fonts, colors, line weights, and ensuring scalability across document formats can become a headache. Enter TikZ, a powerful, native LaTeX package that allows you to programmatically describe every element of your diagram within your .tex file. The result is perfectly integrated, infinitely scalable vector output that matches your document’s typography and can be easily updated, version-controlled, and styled with LaTeX macros.
This post is aimed at LaTeX users who’ve dabbled with simple shapes or seen basic TikZ examples online, but want to level up. We’ll explore eight practical techniques—from drawing basic shapes and connecting nodes to leveraging loops, layers, and pgfplots for data visualization—each illustrated with a “before” snippet (using external graphics or naïve TikZ) and a polished “after” TikZ code block. By the end, you’ll have an arsenal of patterns and best practices to streamline your diagram workflow and create publication-quality figures entirely in LaTeX.
The Problem: Many users start by creating simple shapes in external programs, exporting PNGs or PDFs, then including them. This breaks document consistency and makes edits tedious.
Before (External Image):
\begin{figure}
\centering
\includegraphics[width=0.4\textwidth]{rectangle.png}
\caption{A basic rectangle drawn externally.}
\end{figure}
After (Native TikZ):
\begin{figure}
\centering
\begin{tikzpicture}
% Draw a filled blue rectangle with red border
\draw[fill=blue!20, draw=red, line width=1pt]
(0,0) rectangle (4,2);
\end{tikzpicture}
\caption{A rectangle drawn natively with TikZ.}
\end{figure}
Explanation: In the after code, TikZ’s coordinate system lets you precisely place shapes. The optional arguments fill, draw, and line width give full control over appearance. No external files, perfect integration.
The Problem: Creating flowcharts or network diagrams by manually drawing arrows between coordinates is error-prone and hard to maintain when labels move.
Before (Naïve TikZ without Nodes):
\begin{tikzpicture}
\draw (0,0) rectangle (2,1) node[midway]{A};
\draw (3,0) rectangle (5,1) node[midway]{B};
\draw[->] (2,0.5) -- (3,0.5);
\end{tikzpicture}
After (Using Named Nodes & Edge Syntax):
\begin{tikzpicture}[node distance=2cm, auto]
% Define node style
\tikzstyle{block} = [draw, fill=orange!20, rectangle, minimum size=1cm]
% Create nodes
\node[block] (A) {A};
\node[block, right of=A] (B) {B};
% Connect with arrow
\path[->, thick] (A) edge node {transition} (B);
\end{tikzpicture}
Explanation: By defining nodes with names ((A), (B)), you can refer to them semantically. The edge syntax auto-calculates attachment points and supports labels. Adjust node distance globally for consistent spacing.
The Problem: Repeatedly specifying fill colors, shapes, and fonts for each node or path clutters the code and makes global style changes a chore.
Before (Inline Styles Everywhere):
\node[draw, circle, fill=green!30] (X) {X};
\node[draw, circle, fill=green!30, right=of X] (Y) {Y};
\draw[->, blue, thick] (X) -- (Y);
After (Defining Styles Once):
\tikzset{
myNode/.style = {draw, circle, fill=green!30, minimum size=8mm},
myArrow/.style = {->, thick, blue}
}
\node[myNode] (X) {X};
\node[myNode, right=of X] (Y) {Y};
\draw[myArrow] (X) -- (Y);
Explanation: \tikzset{…} defines named styles (myNode, myArrow) that encapsulate all styling options. Changing a color or shape later is as simple as editing one line.
The Problem: Drawing grids of nodes or repetitive elements via copy–paste leads to bulky code and maintenance nightmares.
Before (Manual Duplication):
\node at (0,0) {1};
\node at (1,0) {2};
\node at (2,0) {3};
\node at (0,1) {4};
\node at (1,1) {5};
\node at (2,1) {6};
After (Using \\foreach):
\foreach \x in {0,1,2} {
\foreach \y in {0,1} {
\node[draw, circle, fill=yellow!30] at (\x,\y)
{\pgfmathtruncatemacro{\val}{\x + 3*\y + 1}\val};
}
}
Explanation: Nested \foreach loops generate a 3×2 grid of numbered nodes. The inline \pgfmathtruncatemacro computes the label automatically. Add or remove grid points by adjusting the loop ranges.
The Problem: In complex diagrams with background highlights, overlays, or watermarks, it’s hard to control which elements appear in front or behind others.
Before (No Explicit Scoping):
\draw[fill=gray!20] (-1,-1) rectangle (4,3); % background
\node[draw] (A) at (0,0) {A};
\node[draw] (B) at (3,2) {B};
\draw[->] (A) -- (B); % ends up under the background fill if order flips
After (Using scope & Layers Library):
\usetikzlibrary{layers}
\pgfdeclarelayer{background}
\pgfsetlayers{background,main}
\begin{tikzpicture}
% Background layer
\begin{pgfonlayer}{background}
\fill[gray!20] (-1,-1) rectangle (4,3);
\end{pgfonlayer}
% Main layer
\node[draw, fill=white] (A) at (0,0) {A};
\node[draw, fill=white] (B) at (3,2) {B};
\draw[->, thick] (A) -- (B);
\end{tikzpicture}
Explanation: Declaring layers and wrapping drawing commands in pgfonlayer environments ensures correct stacking: backgrounds never obscure main content. You can add further layers (e.g., foreground) for annotations.
The Problem: Including plots as images (Matplotlib, Excel) introduces font mismatches, axis style discrepancies, and external dependencies.
Before (External Plot):
\begin{figure}
\centering
\includegraphics[width=0.8\textwidth]{data_plot.png}
\caption{Experimental data plotted externally.}
\end{figure}
After (Native pgfplots):
\begin{figure}
\centering
\begin{tikzpicture}
\begin{axis}[
width=0.8\textwidth,
xlabel={Time (s)},
ylabel={Voltage (V)},
grid=major,
legend pos=outer north east
]
\addplot table [
x=time, y=voltage,
col sep=comma
] {data.csv};
\addlegendentry{Sensor A}
\end{axis}
\end{tikzpicture}
\caption{Voltage vs. time plotted using pgfplots.}
\end{figure}
Explanation: The pgfplots package reads data directly from CSV, matches document fonts, and styles axes consistently. Adjust tick styles, colors, and error bars entirely within LaTeX.
The Problem: Complex TikZ figures can slow down each LaTeX compile dramatically, impeding iterative editing.
Before (Every Compile Renders All TikZ):
% No externalization enabled
\begin{tikzpicture} … complex code … \end{tikzpicture}
After (Using External TikZ Library):
\usetikzlibrary{external}
\tikzexternalize[prefix=figures/] % store PDFs in figures/
\begin{tikzpicture}
… complex code …
\end{tikzpicture}
\end{document}
Explanation: With tikzexternalize, each figure is compiled once and saved as a standalone PDF. Subsequent compiles reuse the cached image, slashing build times for large documents.
The Problem: Manually positioning hierarchical diagrams or mind maps requires tedious coordinate calculations.
Before (Manual Tree):
\begin{tikzpicture}
\node {Root}
child { node {Child A}
child { node {Grandchild A1} }
child { node {Grandchild A2} }
}
child { node {Child B} };
\end{tikzpicture}
After (Using mindmap Library):
\usetikzlibrary{mindmap,trees}
\begin{tikzpicture}[mindmap, concept color=blue!40,
every node/.style={concept, font=\large\bfseries}]
\node{Central Idea}
child[concept color=green!50]{ node {Branch 1}
child { node {Leaf 1a} }
child { node {Leaf 1b} }
}
child[concept color=orange!50]{ node {Branch 2}
child { node {Leaf 2a} }
};
\end{tikzpicture}
Explanation: The mindmap and trees libraries automatically calculate positions and styles for hierarchical layouts. You simply specify parent–child relationships and color themes.
Crafting your diagrams directly in LaTeX with TikZ yields many benefits:
The examples above scratch the surface of TikZ’s capabilities. To deepen your mastery:
animate for dynamic figures in PDF presentations or beamer overlays.By embracing TikZ as your primary diagramming tool, you’ll produce documents that not only convey complex information clearly but also look polished and cohesive. The initial learning curve pays dividends in flexibility, reproducibility, and professionalism. Happy drawing!
tikzpicture (core environment)nodes, \foreach (loops & placement)pgfplots (data plots)external (externalization)mindmap, trees, arrows.meta, backgrounds (specialized libraries)\tikzset (defining custom styles)