Someone sent you a .kmz, and now you need to open a KMZ file. However, double-clicking often does nothing useful. So this guide explains what a KMZ really is. Then it shows three simple ways to open a KMZ file and get your data out.
A KMZ is simply a zipped KML. In other words, it is a ZIP archive. Inside sits a KML document, usually named doc.kml. The archive also bundles any icons, images and overlays the map uses.
Google Earth exports KMZ by default. So the file stays small and travels well. That is also why Notepad shows gibberish. You are looking at compressed binary, not plain text.
Unzip a typical KMZ and the layout is predictable. First, doc.kml sits at the root. It holds the geometry and the attributes. Then a files/ or images/ folder holds the icons. The KML itself is plain XML. Therefore you can read it in any editor.
The quickest way to open a KMZ file is Google Earth. Just double-click the .kmz. Then the placemarks, paths and imagery appear on the globe. So this route is perfect when you only want to view the map.
You can also use the free web version. First, open Google Earth for web. Next, choose File, Import KML file. On Android and iOS, the app opens a KMZ too. However, very large files can struggle on a phone.
Both major GIS tools read KMZ directly. In QGIS, use Layer, Add Layer, Add Vector Layer. Then point it at the .kmz. So no unzipping is needed. In ArcGIS Pro, run the KML To Layer tool instead. For heavy editing, convert the file to a shapefile or GeoPackage first.
Because a KMZ is just a ZIP, you can unzip it. Also, the steps are short:
file.kmz to file.zip.doc.kml plus any images.Now you hold the raw KML. So you can open it in a text editor. Alternatively, you can load it into GIS.
Sometimes Windows hides file extensions. As a result, you may see file.kmz.zip. First, turn on File name extensions in the Explorer View tab. Alternatively, skip renaming. For example, 7-Zip, WinRAR and Keka open a .kmz directly. On a Mac, you can also run unzip file.kmz in Terminal.
The doc.kml file is XML. So an editor with syntax highlighting helps a lot. You can hand-edit names, descriptions and coordinates. However, watch the coordinate order. KML writes longitude first, then latitude. That is the reverse of how most people say it. The format follows the open OGC KML standard.
Often you do not want to view the map. Instead, you want the data somewhere else. For example, a spreadsheet, a shapefile, or plain KML. So the fastest route is to convert it in your browser. Better still, nothing is uploaded.
Choose by your next step. For desktop GIS, pick Shapefile or GeoPackage. However, prefer GeoPackage when field names are long, because shapefiles truncate them. For a web map, pick GeoJSON instead. For a quick list, pick CSV or Excel. Finally, for a handheld GPS, pick GPX.
Most online converters send your file to a server. However, that is risky for sensitive data. Client sites and survey points are good examples. So browser conversion runs locally instead. As a result, the file never leaves your machine. It even works offline once the page loads.
KMZ files often hide attributes in each placemark popup. It may be an HTML table, or it may be ExtendedData. A good converter lifts those into real columns. As a result, your CSV or shapefile gets proper fields, not one HTML blob.
After converting, open the attribute table. Then confirm three things. First, the row count matches your placemarks. Next, the columns are real fields, not a raw description string. Finally, the features land in the right place on the map.
Usually the placemarks exist, but the view is elsewhere. So in Google Earth, right-click the layer and choose Zoom to. If it stays blank, the file may only hold a network link. That link may point to a dead server.
Coordinates of 0,0 are "Null Island". In short, the latitude and longitude were empty. This often happens after a spreadsheet import. Because of that, the coordinate columns were not read correctly.
Question marks instead of accents mean an encoding mismatch. KML is always UTF-8. Therefore your output should use UTF-8 too. For shapefiles, that means a .cpg file next to the .dbf. In short, once you know it is a ZIP, you can open a KMZ file any way you like.
A KMZ is a ZIP archive, so you can rename it to .zip and extract it, or open it directly with 7-Zip or Keka. Inside you'll find doc.kml, which is plain XML you can read in any text editor. QGIS and ArcGIS also open KMZ files directly, and you can convert one to CSV, Shapefile or GeoJSON in your browser without installing anything.
KML is an uncompressed XML text file. KMZ is a ZIP archive containing that KML plus any icons or overlay images it references. They hold the same geographic data, KMZ is simply smaller and bundles supporting files, which is why Google Earth exports it by default.
Yes, via Google My Maps. Create a new map, click Import on a layer, and upload the KMZ. Note that My Maps has feature limits per layer, so very large KMZ files may need splitting or converting first.
Not directly, Excel can't read the zipped XML. Convert the KMZ to CSV or XLSX first; the placemark names, coordinates and any popup attributes then become ordinary spreadsheet columns.
It depends entirely on the converter. Most send your file to a remote server. If the data is sensitive (client sites, survey points, protected locations) use a converter that runs in your browser, where the file is processed locally and never uploaded.
The most common causes are that the attributes were stored in the placemark popup as HTML and were dropped, or the source had no usable geometry. Check the attribute table after conversion: you should see real named columns and the expected number of rows, not a single description field full of HTML.