As the Kent & Sussex chapter of a traveler’s eBook begins, the page shows the current temperature. Just a hint of what’s to come in digital travel guides…

Not enough room in the suitcase? Maybe it’s time to ditch the travel guidebook and try the eBook version instead. I did, and learned a lot about what a traveler’s eBook ought to be.

Travel guides are very different from other types of fiction and nonfiction books. They are only partially read. They are intensely used, but only for a few weeks. They are out of date shortly after they are published. And if you’re doing a lot of traveling, they can become quite heavy.

An eBook on an iPad? Less weight. Full color. An opportunity to integrate with digital maps and Trip Advisor, build an itinerary, make reservations, maybe connect with chapters in history or nature books.

Well, we’re not there yet, but we are seeing the beginning of a new era in travel guides.

Lonely Planet has yet to make its big move into iPad publishing, but they offer one excellent idea: the purchase of individual chapters as PDF files for just under $5 a piece. For example, Lonely Planet’s digital England book can be purchased for $17.49, or you can buy the Devon & Cornwall chapter for $4.95. Either way, it’s mostly well-written text with very helpful guidance, plenty of links, and, take note, designed for iPhone with only with 2x magnification feature on.

Fodor’s London Travel Guide is a full-featured app with plenty of maps, color images, lists with links, and easy access to places to visit, lodgings, restaurants, and nightlife. In fact, the app is organized so that it’s easy to read the text blurb about the London Zoo, then quickly refer to a restaurant map to find Lemonia, a highly-regarded Greek restaurant nearby. Read the description of Portobello Market, click, then there it is on a full-screen map. It’s easy to use and effective.

Working with an eBook design firm called Inkling, Frommer’s offers a more ambitious take on the digital travel guide. The eBook is organized in chapters, but each chapter begins with several points of entry: favorite moments in the region, a three-day trip, a five-day journey, favorite sites to visit, popular destinations in detail, and more. Choose the Cotswolds village of Moreton-on-the-Marsh and there’s a well-written description of the village, tips about what’s nearby, quick access to area maps, and an overall design that’s clearly designed for digital devices. This series is called “Day by Day”, so I expected an itinerary planner to coordinate with my iPad’s Calendar app. That’s not yet a feature, but I suspect it was discussed during this superior product’s design phases.

I used all three guides, often and successfully, and never once missed the books that I did not carry with me. My favorite: Frommer’s. But I suspect that next week’s BookExpo will find publishers to introducing the next generation of interactive travel guides.

What’s next? Certainly, full integration with Google Maps, Trip Advisor, Kayak and other reservations systems, Calendar, email. Those seem to be within reach, but they only scratch the surface of what could be done. There’s a gigantic social network opportunity here, whether it’s couch surfing or house swapping, or simply asking whether anybody in the Pembrokeshire area feels like taking a hike today. Right now, publishers are cautiously experimenting with books that become books on screens, but this caution may result in the demise of yet another industry. Travel publishers possess a unique opportunity to bring places to life, to involve community members (think Zagat’s but on a massive scale), to truly invent the future of publishing on a large, interactive scale. It’s interesting to contemplate whether this work can be done, or will be done, by travel publishers owned by much larger publishing conglomerates, or whether smaller, more flexible and potentially more innovative publishers will map this particular journey into the future.