> For the complete documentation index, see [llms.txt](https://docs.sevenpens.com/drawtab/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sevenpens.com/drawtab/troubleshoot/diag-draw-grid.md).

# DIAG: Detecting digitizer issues by drawing a grid

## Overview

Drawing a regular grid on your tablet can help diagnose certain kinds of problems, such as:

* Digitizer failure. See [TSG: Pen skipping vertical or horizontal bands](/drawtab/troubleshoot/tsg-skipping-bands.md), where regions of the tablet simply do not detect the pen.
* [Electromagnetic interference](/drawtab/guides/general/electromagnetic-interference.md), where things like magnets distort straight lines.

## The Grid to draw

How many lines do you need on the grid? The example below shows roughly the grid to draw.

<figure><img src="/files/QOkVTAMpDCn8GMjKOEJJ" alt=""><figcaption></figcaption></figure>

The example below might also be enough.

<figure><img src="/files/J15eO7HFdfUxJd89XalL" alt=""><figcaption></figcaption></figure>

But the example below is definitely not enough.

<figure><img src="/files/2cezaVsoT2IF6tUWAgPk" alt=""><figcaption></figcaption></figure>

Try to draw them with a ruler, or just try to draw them straight enough by hand. It's important that your lines aren't too "wobbly," otherwise they will interfere with diagnosing problems.