Satellite imagery in Photogrammetry
Posted 16 November 2009 - 08:09 PM
I'm not a cartographer so I really appreciate your help and your patience. I would like to create a hiking map with contour lines and all the topographical features on 1:25,000 scale of a property I own near the mountains in eastern Panama. The problem is that currently, the only other maps for this region of the country are available only in 1:100,000 and 1:250,000 scales.
I talked to some cartographers at the Geographic Institute, and they told me that that information is not available because the region is always overcast, and the folks at the photogrammetry department haven't been able to take pictures of the terrain.
So I was wondering if I can use satellite images to create contour lines? Or do I have to use more conventional photogrammetry methods such as getting on an airplane and taking the photographs myself?
You would think that in this day and age, you could obtain this and all sorts of information from satellite imagery. If so, what is the best source? I've been tempted to buy the Global Mapper software, but first I would like to make sure it's going to give me what I need before I commit to the investment.
Greatly appreciate your advice,
Posted 17 November 2009 - 12:49 AM
Posted 17 November 2009 - 12:58 PM
I am guessing that you are not interested in deriving contours from raw imagery; even if you had the necessary stereo images, stereo-scope, etc., this would be a lot of work. Assuming no contour data are available, you could derive contours from a digitial elevation model (DEM) in an appropriate application (e.g. ArcGIS, Global Mapper, etc.), as well as creating other basic layers for visualization such as a hillshade layer. The next question would be where to get the DEM. The USGS serves up 3sec SRTM data; the resolution is limited, but perhaps adequate for your needs. Hope this helps a little.
Thank you Ed, for your prompt response. I browsed through the USGS website, but realize that none of this is going to be of much use unless I get the appropriate application. I am entertaining the idea of purchasing Global Mapper, but honestly I would like a Mac-based application. I do have Windows 7 on my Mac as a virtual machine. So, if there is no comparable software for Mac, I guess it's not the end of the world. If you have any thoughts on this, I'd love to hear them.
Thank you so very much for all your help,
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