Here are some views of the middle section of the West Woods taken on Saturday.
In this view above, you are looking south from a point about 150 yards due west of the Philadelphia Brigade Monument. This location is in the newly-acquired property that is the West Woods proper. The 59th New York and the far left of the 15th Massachusetts passed over this ground on their way to the Alfred Poffenberger Farmstead.
This section of the woods was cleared in the 1880s and then farmed until a few years ago. At the time of the battle, the woods were filled with widely spaced mature hardwood trees. There was little undergrowth since farmers fenced in crops and let their livestock roam (and graze) freely in the woodlots and other unfenced land. You will notice the newly-planted trees, part of the reforestation going on throughout the park. In about 100 years, the West Woods will look much like it did on September 17, 1862.
The second image is from the same location but looking north. In the distance, just beyond the first set of trees, is Starke Avenue and beyond that the extreme right of Sedgwick's Division over which the First Minnesota passed. You might be able to make out additional reforestation efforts on that part of the field as well. The middle distance is where the 20th Massachusetts stood. The distance between the wood line in the first photo and Starke Avenue is about 500 yards.
I have tried to mark the shooting location and direction of these two photos in order to give you a better sense of where this is on the field. The blue arrows indicate the shooting angle. The southward pointing arrow corresponds to the first photo above; the northward to the second photo. The number indicates that it is the first in a series of photos that I will be posting over the next few weeks. Hopefully this will provide a better reference to view these postings.
The map used here depicts unit positions at 9 a.m.. It is from the Atlas of the Battlefield of Antietam  commonly known as the Carmen/Cope Map. Much of the information about these positions came from Ezra A. Carmen, who was a Colonel with the 13th New Jersey at Antietam. "Within weeks of the fighting [Carmen] toured various sections of the field, interviewed local inhabitants and Confederate prisoners, and began the barest preparations for a map and narrative of the battle--projects he would continue to perfect for nearly half a century."  He carried on "tremendous correspondence with hundreds of fellow veterans of the battle, supplemented by oral interviews and walking tours of the field with his subjects." Carmen drew on this wealth of eyewitness information and recollection to help create the Atlas which has left us with an invaluable understanding of the movement of units at various points throughout the day (there are 14 maps in all).
Click on any of these photos / images to enlarge them.
 Atlas of the battlefield of Antietam / Surveyed by Lieut. Col. E. B. Cope, engineer, H. W. Mattern, assistant engineer, of the Gettysburg National Park. Drawn by Charles H. Ourand, 1899. Positions of troops by Gen. E. A. Carman. Published by the authority of the Secretary of War, under the direction of the Chief of Engineers, U. S. Army, 1904. The 1904 series can be downloaded from the Library of Congress, American Memory Project. The URL is http://memory.loc.gov/cgi-bin/query/D?gmd:24:./temp/~ammem_I7Hy::
 The Maryland Campaign of September 1862: Ezra Carmen's Definitive Study of the Union and Confederate Armies at Antietam, edited by Joseph Pierro (Routledge, New York, 2008), p. x.