Wanting to learn a bit more about the visitors to this site, I thought installing a heat map on the site would be a good start.

I initially used PicNet Mouse Eye Tracking – this is free, but an advert for the service appears at the foot of your site. However, I soon came across the OpenSource ClickHeat. You can use this on any kind of site and is a PHP-based installation.

After much gnashing of teeth, here’s how I got it installed…

• Download the latest version of ClickHeat and unzip it
• Install this into a folder on your server
• Now, from the address bar of your browser, open up the folder. e.g. If you installed it to www.mysite.com/clickheat, you’d go to this directory in your address bar.
• This will start the installer. I found errors straight away – make sure the config, log and cache folders are writeable.
• Done. You simply need to add the code to start tracking – return to the ClickHeat folder to access your heat map and make settings changes.

To test it’s working, simply append ?debugclickheat to the end of any of your sites URLs.

I added the JavaScript (which is generated from the ClickHeat admin screen) directly to my footer.php file in the theme folder, wrapping it in a check to ensure that an admin isn’t signed in (so it doesn’t track my clicking!).

One more problem I cam across – in the ClickHeat admin screens I kept getting the following error…

Warning: ob_start() [ref.outcontrol]: output handler 'ob_gzhandler' cannot be used twice in /xxx/clickheat/index.php  on line 51

Obviously, I’ve replaced the directory path with “xxx” for security reasons.

After some searching around, I decided the best solution was to make a modification to the ClickHeat code itself. Open up the index.php file within the ClickHeat folder and attempt to find the line that starts with the following…

if (@ini_get('zlib.output_compression')

Before this line, add the following…

ob_end_clean();

And that’s worked for me.

I’ll report back on how I get on with ClickHeat.