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  1. #1
    mtbr member
    Join Date
    Apr 2010

    Can't get shaded maps on eTrex 30

    Anyone able to provide a workflow to get shaded topo on the etrex 30?

    I have loaded the Garmin 24k maps via Garmin Map Installer, and have the setting in the map display to show shaded relief when possible. However, even when only the 24k map is visible, no shaded relief shows up.

    I've tried with and without the stock DEM map, which I though was supposed to have shaded relief, too.

    Anyone able to give insight on this?
    idiom - raleigh hard rock

  2. #2
    since 4/10/2009
    Reputation: Harold's Avatar
    Join Date
    Dec 2003
    you're going to find very few people here who know much about the shaded relief in those maps. Most of us get our maps from GPSFileDepot - Free Custom Garmin Maps, Ximage hosting, tutorials, articles and more for your GPSr and I do not recall seeing many maps there that have shaded relief.

  3. #3
    mtbr member
    Join Date
    Feb 2004
    This might depend a lot on where you are using it and what the resolution of their shaded relief "source" is.

    For example the common typical shaded relief maps you see are very coarse resolution.

    The National Elevation Dataset (NED) and the Shuttle Radar Topography Mission (SRTM) datasets are two major ones that are used for nation wide shaded relief layers in GIS, but I believe both are very coarse in their elevation blocks when applied over the whole US. In other words you have to change a huge amount in elevation to change shades. Which makes sense because you have a low of ~-300' in death valley and a high of ~14,500 in CA (not including ~20,000 in alaska). and only the visible colors to go between them so if your scene on the gps only has 500' of elevation change that's not much difference.

    Which would mean that if they are using something similar and you are looking at a small area on the screen it may very well all end up the same color or a couple shades of the same color.

    Ideally you'd have software that was smart enough to figure out the elevation difference over the screen extent you are viewing and reapply the shading based on those limits, but I doubt garmin is doing that, and it would take a lot of processing on the fly as the screen moved.

    I notice the same thing on my Nuvi that provides a shaded 3D view if you have topo data, and it does, but you have to zoom so far out to see the shaded relief effect that it's worthless in real use. Even in areas with high relief I'd have to zoom out so I was seeing 20+ miles of terrain on the screen to get a nice shaded relief image. So it makes a pretty image on the screen but it's not very useful at real navigation zoom levels.

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