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I have a full dataset of the older USGS data that was formerly referred to as "NED1". (One arcsecond data, 1 degree tiles, raster of 3612x3612 floats in a .flt file, .hdr and .prj files included.)

How do I coax GDAL to read these? Is this [older] NED1 format readable by GDAL? Is this format...

  • EHdr -- ESRI .hdr Labelled
  • ENVI -- ENVI .hdr Labelled Raster
  • GenBin -- Generic Binary (.hdr labelled)

... or something else?

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    Yes, they're readable with GDAL. USGS published some Windows batch scripts to convert from float to geotiff which uses GDAL. Have you tried? And what was the problem? A simple gdal_translate input.flt output.tif should output an uncompressed untiled GeoTIFF.
    – user2856
    Commented Feb 23 at 22:16

1 Answer 1

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The problem was simply my unfamiliarity with GDAL. At first it seemed that for most of the functions I had to know the datatype/format of my dataset before I ran any GDAL utilities and it wasn't obvious what the format of my USGS NED1 data was, in terms of supported GDAL inputs.

Turns out:

  • GDAL generally is able to figure out the datatype, so all I have to do is invoke commands on my "n##w###.flt" file and it pretty much just works.
  • This is shown by a simple call to gdalinfo which dumped the text below.
  • The output from gdalinfo gave me the specific answer to my question: that data is considered format "EHdr/ESRI .hdr Labelled". (Which I had never heard of before... and I've been working with this dataset for a LONG time.)
# output from: gdalinfo NED1/n24w098/floatn24w098_1.flt

Driver: EHdr/ESRI .hdr Labelled
Files: NED1/n24w098/floatn24w098_1.flt
       NED1/n24w098/floatn24w098_1.hdr
       NED1/n24w098/floatn24w098_1.prj
Size is 3612, 3612
Coordinate System is:
GEOGCRS["NAD83",
    DATUM["North American Datum 1983",
        ELLIPSOID["GRS 1980",6378137,298.257222101,
            LENGTHUNIT["metre",1]]],
    PRIMEM["Greenwich",0,
        ANGLEUNIT["degree",0.0174532925199433]],
    CS[ellipsoidal,2],
        AXIS["geodetic latitude (Lat)",north,
            ORDER[1],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["geodetic longitude (Lon)",east,
            ORDER[2],
            ANGLEUNIT["degree",0.0174532925199433]],
    ID["EPSG",4269]]
Data axis to CRS axis mapping: 2,1
Origin = (-98.001666666670005,24.001666666664136)
Pixel Size = (0.000277777777778,-0.000277777777778)
Corner Coordinates:
Upper Left  ( -98.0016667,  24.0016667) ( 98d 0' 6.00"W, 24d 0' 6.00"N)
Lower Left  ( -98.0016667,  22.9983333) ( 98d 0' 6.00"W, 22d59'54.00"N)
Upper Right ( -96.9983333,  24.0016667) ( 96d59'54.00"W, 24d 0' 6.00"N)
Lower Right ( -96.9983333,  22.9983333) ( 96d59'54.00"W, 22d59'54.00"N)
Center      ( -97.5000000,  23.5000000) ( 97d30' 0.00"W, 23d30' 0.00"N)
Band 1 Block=3612x1 Type=Float32, ColorInterp=Undefined

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