In my last post on Mobile measurement I talked about some of the key challenges that really differentiate mobile from fixed web measurement. Because of those challenges, organizations have to make a decision between using a completely different measurement solution for mobile, using their existing solution with javascript tags, or modifying their existing solution by using image tags. If you’re going this last route, we’ve found that it’s convenient to have an easy way for developers to generate mobile image tags – particularly in the early stages of testing. The Excel Mobile Image Tag (EMIT) generator makes generating efficient and correct image tags a snap.
The EMIT generator is something we built internally for our own use and we’ve given versions of it to various clients. We felt like it was too simple an application to really charge for. But we also found that it was enough of a time saver to be genuinely valuable. So we’ve opted to make it available on our website in a new “Featured Items” section. This does require a very light-weight registration (yes – you’ll get our emails – but that’s not all bad) but otherwise it’s free. In addition to the EMIT generator, there are a couple of our newest white papers including Paul’s Microsite Measurement and my latest with Netezza’s Brad Terrell on Warehousing Analytics. All good stuff.
But today I want to focus on the image tag generator.
Creating image tags is a little different than creating traditional javascript tags. Images need to be configured from a standard template on the server side (before they are inserted into the HTML stream). To do this, developers typically work with a basic image tag template and then write code to substitute the necessary values.
For Omniture image tagging, this process is made a little bit harder by the need to shorten the tags as much as possible and the subsequent use of substitution variables.
Using the EMIT generator, you start by defining which variables need to be included in the template tag.
You also enter sample values for these variables. These should be of representative or maximum possible length – depending on how conservative you want to be about image request size. The tool does the basic transformations for you so that a correct value gets inserted into the sample image.
The next step is to set the variables you want to define from other variables. In Omniture, there are quite a few cases where you might want to do this. It’s very common to set a prop and an eVar to a single value. Instead of copying the value twice into the image request, it’s vastly more efficient to set one value first (the prop for instance) and then set the next value (the eVar) to the prop. The order of assignment makes a big difference here, and the generator makes sure that the sample images come out right. That’s critical if you’re using these sample images for server-side templates.
Once you’ve done this, the tool automatically generates the image request. This is a fully and correctly formed image that can be used for testing or as a server-side template. The tool also calculates the total length of the image and uses conditional formatting to highlight the length if it may be too long.
The generator has one other nice feature that is surprisingly handy – it can deconstruct and image tag back into its constituent pieces.
The world being what it is, sooner or later you’ll find yourself testing an image tag and not being sure how it was encoded. You can decipher it without too much brain strain, but it’s easier to just pop it back into the tool and let Excel do the nice parsing. That’s also a good way to find otherwise obscure formatting issues that will impact how the image is parsed.
I think you’ll find this is a handy little tool – particularly if you’re just getting started with mobile image tagging. Enjoy!

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