If you download the 7.5' quads in the tif format you get separate rasters with 
the image in one and the usual topographic layers in the other. According to 
the USGS, the geopdf was never meant to be a GIS compatible product. You can 
get the individual data layers from the National Map if you want to create your 
own custom version.
Regards, Rick
________________________________
From: Qgis-user <[email protected]> on behalf of 
[email protected] <[email protected]>
Sent: Tuesday, April 21, 2020 12:45 PM
To: Mike Flannigan <[email protected]>; [email protected] 
<[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: [Qgis-user] 2019 USGS 7.5min topo sheets

I am running Qgis 3.4.2 on Windows and I can load the new style geopdf USGS 
7.5' quads, including the imagery layer.
It's slow and grinds qgis to a halt while it loads, but it does work. The 
different layers, which are independently controllable in Acrobat Reader are 
flattened when the topo is opened in Qgis, which rasterizes the image and 
presents it as one raster, not separate layers.
USGS has made these maps much less useful by adding the aerial imagery layer, 
at least for me. Qgis isn't the only application that flattens the layers, and 
the imagery obscures way to much for my taste.

On 4/21/2020 12:22 PM, Mike Flannigan wrote:

Much to my surprise I think you are correct.
QGIS can open a TIF file (and a zipped TIF file),
but I can't get a GeoPDF to open in QGIS.  If I
convert the GeoPDF to a TIF with GDAL, it still
will not open and gives error "Missing Codec".

Very surprising.  I know from past experience that
Global Mapper v6.04 will view TIF files that have
been converted from GeoPDF via GDAL.


Mike


On 4/20/20 5:00 PM, 
[email protected]<mailto:[email protected]> 
wrote:
It sounds like you downloaded a new USGS product format called the GeoPDF. The 
".pdf" suffix is the big clue. I don't know if QGIS 3.2.3 can read those files. 
I would try downloading the map in a different format. I don't know what site 
you are using, but the USGS TopoView site (https://ngmdb.usgs.gov/topoview/) 
has the maps available as JPEG, KMZ, GeoTIFF, and GeoPDF. I would recommend the 
GeoTIFF format as all versions of QGIS support that.

Best,
    ++Eric Fielding


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