KML/KMZ: Make one placemark appear in two folders?

KML/KMZ: One Placemark, Many Homes? How to Bend the Rules

So, you’re diving into the world of KML and KMZ files, huh? These are the go-to formats for showing off geographic data in cool Earth browsers like Google Earth. Now, you’ve probably run into this head-scratcher: you want a single placemark – that little pin on the map marking a spot – to pop up in multiple folders. Makes sense, right? Organize your data different ways without a ton of extra work. But here’s the thing: KML doesn’t exactly make it easy.

Think of it like this: in your computer’s file system, you can create shortcuts or aliases, so one file seems to live in several places. KML? Not so much. It’s built on XML, where everything, including each placemark, is spelled out in detail. No shortcuts allowed! So, how do we get around this? Let’s explore some clever tricks.

The Brute Force Method: Just Copy It!

Okay, it’s not the prettiest solution, but sometimes the simplest way is best. Just copy and paste the whole chunk of code into every folder where you want it. Boom, done!

Why it works:

• Super easy to do.
• Works pretty much everywhere you open the KML.

But… (and it’s a big but):

• Your file gets bigger, faster. All those copies add up.
• Nightmare to update! Change the placemark’s name? Gotta do it in every single copy. Ugh.
• Things can get confusing. Are those really the same place, or just look-alikes?

Here’s a pro tip, though: If you go this route and want to avoid a cluttered map, you can make the labels of the duplicated placemarks invisible. It’s like a sneaky symlink…sort of. Just remember, changes to one won’t affect the others!

Network Links: The “Call Home” Approach

Ready for something a bit more sophisticated? This involves using Network Links. Basically, you create a separate KML file that only contains the real placemark definition. Then, in each folder of your main KML file, you put in a Network Link that points to that external file.

The Upside:

• One placemark to rule them all! Update it once, and everything updates.
• Keeps your main KML file cleaner.

The Catch:

• More complicated to set up initially.
• You need to host that external KML file somewhere – a web server or a shared drive.
• It relies on the KML viewer actually following those Network Links. Sometimes, they don’t.

I remember spending hours wrestling with this method, only to find out Google Earth wasn’t playing nice with my local file paths. Lesson learned: test, test, test!

Radio Folders: The Illusion of Choice

Here’s another clever trick, though it’s not exactly the same thing. Use the tag with set to 1. This turns a folder into a “radio button” setup – you can only see one sub-folder at a time.

Why it’s useful:

• Avoids the clutter of seeing duplicate placemarks.
• Fairly easy to set up.

But:

• Doesn’t really put the placemark in multiple folders at once.
• Locks the user into only viewing one folder at a time, which might not be what you want.

Key Things to Keep in Mind

• KML Viewers are Quirky: What works perfectly in Google Earth Pro might look wonky in Google Maps. Always double-check in your target viewers.
• KMZ is Your Friend: If you’re using Network Links, package everything into a KMZ file. It keeps all the pieces together.
• Unique IDs are a Must: Make sure every Placemark and Folder has a unique ID. KML demands it!
• Relative URLs for Images: If you’re using images, keep them inside the KMZ and use relative URLs to point to them.

The Bottom Line

While KML doesn’t have a simple “symlink” button, these workarounds can get you pretty darn close to having a single placemark live in multiple folders. The best approach depends on your project’s needs. Think about file size, how easy it is to update, and whether it’ll work reliably for your users. With a little creativity, you can bend KML to your will and create some seriously impressive geographic visualizations.