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After hitting my head against the table for many days, I'm humbly presenting myself to the QGIS community.

I downloaded 4 IMG files (1/3 arc second, elevation data) from The National Map on the USGS website. I then loaded these into QGIS v 2.4 and went through the following steps with each section.

First, I converted the raster from meters to feet using the Raster Calculator (outputting to a GEOTiff file and using the current layer extent).\

Next, I used the DEM(terrain models) tool to create a hillshade raster layer.

I'm assuming my adding of contours doesn't matter.

Why is there a line that forms between the sections? The data is supposed to be seamless between the layers.

Also, my Project CRS is NAD83.

enter image description here

  • @AndreJ, looks like you are correct. When I don't convert from meters to feet, I do not get that band. However, now when I try to create a hillshade layer, I'm getting the error message " Float32 Unable to create dataset /Volumes/Reed Sound Drive/Hiking Guide/Second Edition QGIS/2nd Edition QGIS Project/Layers/Hillshade/39120_hillshade_meters 5 Pixel type must be Float32". If it isn't one thing, it's another. Thanks for helping out! Seems like I'm getting closer. – Reed Oct 31 '14 at 20:26
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The line might be from rounding issues when converting from meters to feet.

For the error in Hillshade creating, try to change the datatype from integer to float with gdal_translate:

gdal_translate -ot Float32 src_dataset dst_dataset

You can do that in QGIS too with Raster -> Conversion -> Translate, using the command line box in the form. Maybe it is even possible to run the raster calculator successfully after that step.

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So, it looks like if when I create my hillshade layer using the DEM(terrain models) tool, I need to click "compute edges". This seems to take care of the problem, at least for that layer.

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