3

I have downloaded a KMZ file containing global elevation information. I have tried to convert the data to a shapefile using qgis (save as shape option) and using the zonum solutions website but both times the conversion has not worked.

When using qgis to convert, the new shape file was empty and all attributes were 'NULL'.

Any idea on how to get around this? The KML/KMZ files I am using is from the Marine Geoscience Data system and is available from their website on the following link http://www.marine-geo.org/link/download.php?data_uid=14255&client=DataLink.

4

I think you may need to process this file yourself - either manually, or by writing a script to automate the extraction.

If you rename the file GMRT.kmz to GMRT.zip you can open it in WinZip or similar, and see its contents.

This includes the file doc.kml, which contains a number of Links - examining the first link shows a URL:

<Link>
  <href>http://www.virtualocean.org/cgi-bin/GMRT?wesn=-180,-144,-90,-54</href>
  <viewRefreshMode>onRequest</viewRefreshMode>
</Link>

Open the URL http://www.virtualocean.org/cgi-bin/GMRT?wesn=-180,-144,-90,-54 and note that this downloads a new KML file. Open this file in a text editor and see the first ICON image:

http://www.virtualocean.org/data/tiles/geographic/geographic_512/0/0/0_7.jpg

You can download and georeference this image using the coordinates in the KML file:

<LatLonAltBox>
  <north> -54 </north>
  <south> -90 </south>
  <east> 108 </east>
  <west> 72 </west>
</LatLonAltBox>

So if you're unable to process this file automatically using tools in QGIS, you could automate the process using the above manual steps.

1

That loads two raster layers in Google Earth.

I don't think QGIS (through GDAL) supports reading that KMZ (not a KML) because of it.

ogrinfo below can't recognize the geometry, even with the libkml (google) driver.

ogrinfo -ro -so GMRT.kmz -al
ERROR 1: ERROR Parseing kml Style: No id
ERROR 1: ERROR Parseing kml Style: No id
INFO: Open of `GMRT.kmz'
      using driver `LIBKML' successful.

Layer name: GMRT
Geometry: Unknown (any)
Feature Count: 2
Layer SRS WKT:
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        TOWGS84[0,0,0,0,0,0,0],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0,
        AUTHORITY["EPSG","8901"]],
    UNIT["degree",0.0174532925199433,
        AUTHORITY["EPSG","9108"]],
    AUTHORITY["EPSG","4326"]]
Name: String (0.0)
description: String (0.0)
timestamp: DateTime (0.0)
begin: DateTime (0.0)
end: DateTime (0.0)
altitudeMode: String (0.0)
tessellate: Integer (0.0)
extrude: Integer (0.0)
visibility: Integer (0.0)
drawOrder: Integer (0.0)
icon: String (0.0)

Layer name: High Resolution Areas
Geometry: Unknown (any)
Feature Count: 2
Layer SRS WKT:
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        TOWGS84[0,0,0,0,0,0,0],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0,
        AUTHORITY["EPSG","8901"]],
    UNIT["degree",0.0174532925199433,
        AUTHORITY["EPSG","9108"]],
    AUTHORITY["EPSG","4326"]]
Name: String (0.0)
description: String (0.0)
timestamp: DateTime (0.0)
begin: DateTime (0.0)
end: DateTime (0.0)
altitudeMode: String (0.0)
tessellate: Integer (0.0)
extrude: Integer (0.0)
visibility: Integer (0.0)
drawOrder: Integer (0.0)
icon: String (0.0)



You can probably add the Web Map Service as a layer in QGIS from MarineGeo though!

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