History 615


Fun with NSD and Harpers Ferry…
October 16, 2010, 2:54 pm
Filed under: History 615

I actually started experimenting more in depth with Natural Scene Designer last weekend, was having fun, and just kind of kept going with it, putting off other stuff (like the Martin Brückner reading).  I had wanted to post this up last Tuesday, but just never got around to it.

So here’s my map I started with…

You may recognize it from one of my earlier posts (but without the elevation contours).  Its a military map of Harpers Ferry, West Virginia from 1863.  The map comes from The Atlas to Accompany the Official Records of the Union and Confederate Armies, which was also the source for the “Routes and Positions” map I used in my Illustrator made freehand map.  Again, the map can be found here…

http://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~26871~1100170:Military-map-showing-the-topographi

While the topography here at Harpers Ferry is no Grand Canyon, I feel that when combined with this map in NSD, it makes for some really fascinating views and perspectives and adds a whole new element to the historical analysis of Harpers Ferry during the Civil War.

To give you a sense of the overall topography, here is the map after I georeferenced it in ArcMap and overlaid it on top of the elevation data in NSD.

I tried to get as much of the map as I could to line up properly with the elevation data, but seeing as how this map was produced in 1863, its unlikely that I would be able to get all parts of the map to match perfectly.  There are areas where the topography in the map suggests there should be cliffs but in the scenes they are on flat ground (such as the eastern banks of the Shenandoah), and train tracks running on the edges of hillsides (such as those seen in the views from Fort Duncan), but I think that really these are only minor issues and don’t really takeaway from the overall use of the maps.

So below you will find all the scenes I’ve created from different locations across the map.  I tried to make sure that I picked camera locations that produced views from significant spots such as military positions or hill tops.  I haven’t had the time to test out the flyby camera functionality yet, but maybe that is something I will try to do before next week when this assignment is really due.  We’ll see though, I’ve got a lot of reading to catch up on and thinking to do about my final project topic…

The following are pictures generated from key military positions on the Maryland side of the Potomac starting at the six gun battery on Maryland heights and working downhill and to the west from there.  All are oriented so that they look towards the town at Harpers Ferry.

Looking down on Harpers Ferry from the six gun battery on Maryland Heights…

View of Harpers Ferry from the naval battery which you can see just down and to the right in the image above…

Views looking East/Southeast towards Harpers Ferry/Bolivar from Fort Duncan…

I also wanted to get some shots from the Union line in between Bolivar and Harpers Ferry.

Looking east towards Maryland and Loudoun Heights from the Union line defending Harpers Ferry…

Looking west towards Bolivar from the Union line defending Harpers Ferry…

When you consider the rivers to the left, the right, and the river junction behind you, it appears that the Union had a nice, well defended triangle with only one direction to really worry about being attacked from (as seen in the picture above).

Now the Civil War generally doesn’t fall under my area of historical interest, and therefore my knowledge of that period is somewhat limited, but I do know this.  Harpers Ferry is steep in Civil War history and was definitely a major place of interest as it changed hands between the Union and Confederacy multiple times throughout the war.  It was not only the location of an arsenal, but with several key railroads coming into and through the town, it was a very important location to maintain along the supply line to Virginia.  Looking at the map, Harpers Ferry seems pretty well defended by Union troops, and the pictures above I think just reinforce that notion.  For a town that seems to be so well defended, its odd to me that it could have been taken back and forth like it did.

So what if you were to attack Harpers Ferry?  If you were to attack from the SW, which because of the terrain and the rivers surrounding the town would most likely where you would be coming from, the following are pictures of what you might see…

Looking east towards Harpers Ferry from the northern part of Bolivar Heights…

Not a whole lot of room to work there.

This is probably my favorite scene, the main route to Harpers Ferry via Charlestown Pike…

In the foreground you can see Union front lines on Bolivar Heights, and further back you can see the Union lines closer to Harpers Ferry, Fort Duncan in the top left across the Potomac, the proposed Union position to the right of Fort Duncan, the naval battery to the right of that, and the six gun battery higher up to the right of that.  Not a very welcoming site if your goal is to take Harpers Ferry from those who occupy it.   But in the picture above you also see Loudoun Heights in the top right.

A quick internet search on the Battle of Harpers Ferry, and it appears Loudoun Heights may have been key.  And for good reason, check out the views below…

Looking down on Harpers Ferry from Loudoun Heights…

Imagine Union troops at the main line at Harpers Ferry trying to fend off Confederate troops coming from Bolivar with artillery raining down from Loudoun Heights behind you…

Apparently at the main battle of Harpers Ferry, Gen. “Stonewall” Jackson and the Confederate troops managed to surround the Union forces in that forementioned triangle that seemed so well defended in the pictures above.  After taking Loudoun Heights he ordered an artillery barrage from said location onto the Union forces hunkered down at Harpers Ferry, forcing them to surrender.  The Union simply had nowhere to go.  The Confederacy didn’t have to partake in a full on attack of those Union troops defending the town.  The topography allowed the Confederacy to seige Harpers Ferry instead, as one would a castle, which I think is essentially what Harpers Ferry had become.

While technically I could have figured all of this out by really scrutinizing the original map, viewing the map as it would appear naturally on the surface just illustrates it all in ways I probably wouldn’t have envisioned otherwise.

So after all this I few tips I have for working in NSD…

1) Try adjusting the placement of the light source.  The default placement in NSD seems to be from the SE corner of the map.  Yet standard practice is generally for the light source to be placed in the NW corner of the map (see http://www.reliefshading.com’s design section on light direction here).  Make sure you also try the interactive light direction tool with the Grand Canyon here so you can get a better feel for how much light direction can really change how you read and perceive elevation in a map.

Look at my picture below and then look at the one I posted at the top.  In the picture below the terrain appears to be reversed, and the mountains look like valleys.  In the picture below the light source was in the SE.  In the picture at the top the light source was in the NW.  It wasn’t until after I rendered ALL of my other pictures and rendered the scene below that I realized something was wasn’t quite right with the light direction.

The light directions is less of an issue though when you render pictures at ground level, but it can make a difference and sometimes it may be better not to have the light source in the NW.  Look at the two pictures I rendered below.

Both are views taken from Loudoun Heights looking down on Harpers Ferry.  The one on the top has the light source set from the SE and the on on the bottom has the light source set at the NW.  In this specific case I think having the light source set to the SE makes the scene more effective in that it creates shadows and therefore better portrays how high Loudoun Heights actually is above the river junction and Harpers Ferry.  So try adjusting the light source and see how it changes your scenes.

2) When you render your picture, set your “Anti-aliasing” and “Maximum Levels” bar as high as your computer will allow.  It takes more time for the picture to be created, but I found that the pictures were of much better quality. 

3) NSD only gives you limited functionality for placing and adjusting non-georeferenced overlays.  If you are using a USGS map that you downloaded with your elevation data, that map already has Lat and Long coordinates associated with it and you have nothing to worry about.  If you want to use a historical map or some other map without a coordinate system associated with it though like I did, you may have a harder time getting your map and the elevation data to match up.  Essentially you can make your overlay bigger or smaller, but I couldn’t find a way to rotate it in NSD.

I didn’t try this, but I think the following would probably work as sort of a georeferncing work around.  What I would suggest if you want to use another map is to bring that map and a USGS map into photoshop.  Apply a transparency to your map and then reshape, resize, and stretch your map so that major features such as rivers, boundaries, roads, or other easily identifiable features match up with those on the USGS map.   Then in NSD you can bring in your USGS map using the “Import DRD or DOQ” and then bring in your map using the “Import Overlay” option.  Then all you have to do is line up your adjusted map with your USGS map and then get rid of the USGS map.

4) Pick a large scale map (something at a local level/more detailed).  Use a 24K (1:24,000) USGS map if you are going to use one of those, not a 100K (1:100,000).  It’ll probably be less difficult to match up with the terrain and when you render your pictures the text and other features on the map will be more legible.

And now I have some final project research to do and some reading to catch up on…

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4 Comments so far
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I think you did an awesome job with these images. The elevation and the water, and your map selection for the overlay, made for some really great images that add a lot of perspective to the events at Harper’s Ferry.

I tried to follow your ideas in (3) for overlaying a map without georeferencing, but had to make up a different way. I thought it was a great idea, but I guess I’m not familiar enough with photoshop to make it work (and my map was probably too flat).

Comment by carawhiting

[…] week I commented on Dan’s post and Rodney‘s project. This entry was posted in comments. Bookmark the permalink. ← […]

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Ok, this is great. It is actually significantly better than looking at equivalent pictures would be in some ways (at least in my opinion) because of the way sight lines would get fouled by objects. The entire area is covered in forest, so it is hard to get a clear view that shows the valley like that. Assuming an unlimited supply of time and resources, one could also go out and determine average tree height and building placement during the Civil War and recreate those aspects. Of course, that would take a rather large commitment of time, but it COULD be done. Overall, what you produced looks really, really good, and you offer some neat tips that I’m going to use as soon as I think of something to use them for!

I ran into the same problems with aligning overlays in NSD, including ones that I downloaded from the USGS site along with my elevation data! I think your tip might work, for those of us that don’t have the GIS tools you have at your disposal.

Comment by Daniel Miller

[…] I left a comment on Rodney’s Blog […]

Pingback by Comments for October 21 « Cartography and Maps




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