Trying to recreate Elevation Map from UC2010 Making Beautiful Maps... with GIS!
I am attempting to recreate the Elevation Map that was shown at UC2010 in the Making Beautiful Maps... with GIS! lecture, and have run into a few problems.
I downloaded the Etopo1 bedrock 4-byte/32-bit float and converted it to a ESRI grid with the "Float to Raster" command. I then ran the Hillshade command using the default settings and the output does not even resemble the hillshade from your lecture (it is much darker, more pixelated, and only has units from 0-196 instead of 0-254 - see attached jpeg).
1. How did you break out the icecaps to color? There are two Etopo1 downloads, bedrock and icecap. I am assuming some sort of subtract command to determine exactly which areas are ice to display as ice...
2. I see the colormap that you used to color your map was obtained from an outside source that created it. Is there a sample colormap for an application such as this that is ESRI property or public domain that can be downloaded? If not, how does one go about making one that will work without having to type out nearly 20K lines of RGB colors?
3. If not available, I was trying to use a tool that I found on a blog on this site - "Geoprocessing to split elevation into topography and bathymetry" from August 2007 on how to split a Raster at a specific elevation. On trying to run it I find that you must have a Spatial Analyst license (which I don't have) to use it. Is there another way to do this so as to be able to use two color ramps (one for elevation and one for bathy) to produce the same effect as the colormap in question 2 above.
Thanks for the help.
Mapping Center Answer:
To get the hillshade to look the same as ours you need to project the DEM data before you create the hillshade. The converted DEM data do not yet have linear units (it is still in a geographic coordinate system). Simply project your data (I projected the etopo1 data into a Robinson projection because I was making a world map), and then you will be able to create the hillshade correctly.
Berfore I answer the rest of your questions, I want to note that we will soon be posting this map, along with the data and all the resources used to make the map, on our Maps page so you can download it from there and see how it was made. Now on to your other questions:
1. To get the icecaps, I used other data -- they came from the Natural Earth Data web site (http://www.naturalearthdata.com/downloads/10m-physical-vectors/). I had to do a bit of clean up but it was not major. All of the processing, like this, for any layer is documented in the Layer Properties of the layer.
2. I will also include the colormap file with the map. Dr. A Jon Kimerling of Oregon State University created it so all the credit goes to him.
3. The colormap file is really the way to go for this part of the process.
Hope this helps! And look for the map soon!
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