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I have been using a KMZ file that has every county in the state of Texas throughout the state's history. I can choose a date on a timeline and see the county boundaries as they were set on that date. I can click on the county and get a popup showing the date it was created or last changed, which neighboring counties it added territory from or ceded territory to, and more. I can also choose which county or counties I want displayed from that date, so if I want to make a map focusing on a specific county or set of counties, I can. If it helps for the purpose of answering my question, the KMZ file was obtained here: https://digital.newberry.org/ahcb/

In Google Earth Pro and in ArcGIS Explorer Desktop, I can do everything with this KMZ file stated above. However, I require basemaps that Google Earth Pro does not have and that no longer work with ArcGIS Explorer Desktop, which is quite old. I am checking out QGIS. While it will import the KMZ and let me choose a date for the map, that's all I've gotten it to do. I can't see any way to select/unselect individual counties to be displayed. Whereas Google Earth Pro and ArcGIS Explorer Desktop listed each polygon (county) in the layer as a separate object with its own properties, QGIS simply shows a single mass layer (see the image below). I also don't see any way to access the popup information. KMZ in ArcGIS vs QGIS

To add the KMZ into my QGIS project, I'm dragging the file into the map pane. The "Add layers to a group" and "Show system and internal tables" checkboxes don't have any apparent effect.

Can someone tell if if there is a way to make this KMZ file fully functional in QGIS, the way it is in Google Earth Pro and ArcGIS Explorer Desktop, with individually selectable polygons and notes, and if so, how?

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    you may need to convert your KMZ file to a better format - KML is a display format not really designed for analysis work
    – Ian Turton ♦
    Aug 30, 2022 at 18:52
  • "better format" in QGIS context could mean Geopackage (or Shapefile, if you intend to share with people who don't use QGIS).
    – Babel
    Aug 30, 2022 at 19:57

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The problem I see with the KMZ is that QGIS attempts to display it using the symbology (colours, styles etc) defined in the KMZ, and this seems to result in invisible polygons.

If you go to the Symbology tab and change to "Single Symbol" (right-click on the polygon layer, choose Properties then Symbology section) and set the style to something visible. The counties should appear.

Right-clicking and showing the attribute table will show the name of the date columns etc for you to test and filter by as needed.

Note KMZ isn't really a great general GIS format, there's a link on that site to download a ZIP of "GIS Files" which seems to have the data in Shapefile format which might work better here.

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    KML, the only time that shapefiles seem like a better idea
    – Ian Turton ♦
    Aug 31, 2022 at 6:16
  • Your instructions for displaying the attribute table worked, but from there, it doesn't seem very clear-cut on how to select, say, a single polygon for display. I found the shapefiles you referred to on the Newberry site and will see if they work better in QGIS than the KMZ file. Thank you.
    – davo
    Aug 31, 2022 at 15:35
  • There's a couple of ways - either change the symbology to "rule based" and match on the region name you want to display, or use the "filter" function - check a QGIS tutorial for more.
    – Spacedman
    Aug 31, 2022 at 21:29

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