[GIS] How to combine layers in Google Maps

google earthgoogle mapskmlkmzlayers

Though there are many answers to this question on the Web, I've found none that are recent or correct.

The prevailing view seems to be that one exports a KMZ from Google Maps which one then edits in Google Earth where it is supposed to be possible to simply drag an element from one folder to another. This doesn't work for me.

There's no way in Google Earth to move an element from one folder to another that I can see.

What is the (currently) correct way to combine layers in Google Maps?

Best Answer

As far as I'm aware, No there is no such feature that performs the actions you are specifically looking for. As a workaround, you could export the layers as KML, import them into My Maps, that will get rid of the folder hierarchy creating a single layer map, and reimporting the custom map to MEL into a new layer.

As a step by step here:

If you want to combine two My Maps custom maps:

Go to first map and select "Add a New Layer"
Go to the second map and in the top menu ( three dots) and choose Export to kml-->save the file to your computer
Go to first map, click into the new layer and choose Import--> import the kml file you previously saved.
The two maps are combined.

There is no other method for combining maps in My Maps

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[GIS] Select more than one place at a time in Google Earth

If you have your placemarks in order in the kmz file, the task will be fairly simple (and can be accomplished in a text editor). Either save the placemarks as a kml file (right click and "Save place as"), or change the file extension of the kmz file to zip and extract the zip file (a kmz file is simply a zipped up kml file(s)).

Here you can open up the kml file with any text editor. After figuring out what placemarks you want to be included in each folder, simply place the following text before the first placemark that you want to be included in the folder (here is the KML reference page);

<Folder>
  <name>MYFOLDER_NAME</name>
  <Placemark>

Then when you find the last placemark you want to be included in that same folder, place the closing folder tag;

  </Placemark> 
</Folder>

Then repeat until you have all your placemarks in folders as desired. Tedious, but if a one time job and you only need a few folders, it shouldn't take more than a few minutes copying and pasting into the appropriate spots.

If your kmz file is not sorted appropriately, this won't work. If that is the case, you need to either sort the file before its creation, or utilize other software to read in the kmz file and sort it. If you have access to ArcGIS, you can use a tool to change the kml file to a shapefile, then sort the shapefile accordingly in ArcMap, and then export the KML file. ArcMap has built in functionality to do this, but this script has worked incredibly well for me in the past (Export to KML). If you don't have access to ESRI products, you will have to ask someone else besides me how to sort the placemarks in the KMZ file!

[GIS] Bulk edit and merge KML files

This sounds like a job for some scripting!

KMZ files are zipped KML files (rename it to .zip, and extract, to find the KML.) KML files are essentially XML files, a type of markup language which is readable in programs like Notepad++.

If you open the KML file in a text editor, you get stuff like this:

<?xml version="1.0" encoding="utf-8" ?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document id="root_doc">
<Schema name="missoulaparcel_subset" id="missoulaparcel_subset">
    <SimpleField name="gid" type="int"></SimpleField>
    <SimpleField name="parcelid" type="string"></SimpleField>

...etc

What you can do is identify the parts of a KML file that refer to individual features, and stitch them together into one (much larger) file. It appears as though the Placemark tag starts a feature, and /Placemark ends it - so it should be possible to (relatively easily) write a script to extract all of these features, and append them into a single file.

Alternatively, it looks like there are libraries like pyKML which can operate on KML files. I would probably try to use that, if I didn't feel like writing a script to do it manually.

Best Answer

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[GIS] Select more than one place at a time in Google Earth

[GIS] Bulk edit and merge KML files

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