Contemporary Battle Map -Wrong

[Pvt.Shattuck]

This 1863 map from the LOC by Robert Knox Sneden caused me considerable confusion researching my ancestors location when he was captured. Salem Church has not mysteriously moved over time. It is still located south of the Orange Plank Road (Rt.3), where Confederate shooters poured fire into the left flank of the 16th NY, who were fighting north of the road with Brooks Division.
I just couldn't accept that an 1863 map was wrong. Valuable lesson.
The OR claims there was no one to their right and they were in danger of being surrounded after the 23rd NJ fell back in front of the church.

 

[Andrew]

I was looking at one of Sneden's maps of Antietam only to find out later that he wasn't actually at Antietam. I think he made the maps by referring to reports and maps filed away in DC somewhere.

 

[MajGenl.Meade]

I think it must have moved - here's confirmation

 

[AndyHall]

Sneden was a CW veteran, but many (most? all?) of his maps and illustrations were done postwar. They're valuable, but not as authoritative as those prepared at the time by cartographers and engineers, which are sometimes also inaccurate.

 

[E_just_E]

Another thing that one absolutely needs to take into consideration with older maps, especially if trying to superimpose them to current satellite aerial views and pulling their hair out because they will not match: The magnetic North has been shifting and that causes a small but pretty visible variation between Civil War era maps and today's aerial photos, oriented with North up top...

 

[RobertP]

Another thing that one absolutely needs to take into consideration with older maps, especially if trying to superimpose them to current satellite aerial views and pulling their hair out because they will not match: The magnetic North has been shifting and that causes a small but pretty visible variation between Civil War era maps and today's aerial photos, oriented with North up top...

I got curious and found this map. Magnetic north has moved about 700 miles in the last 150 years. However, since the movement has been almost precisely along a line of longitude that runs through the eastern US I don't think you will see a meaningful difference on a map between magnetic north in the CW era and now, unless you are surveying for very precise details.

"In the last 150 years, the pole has wandered a total of about 685 miles (1102 kilometers)"

 

[E_just_E]

I got curious and found this map. Magnetic north has moved about 700 miles in the last 150 years. However, since the movement has been almost precisely along a line of longitude that runs through the eastern US I don't think you will see a meaningful difference on a map between magnetic north in the CW era and now, unless you are surveying for very precise details.

"In the last 150 years, the pole has wandered a total of about 685 miles (1102 kilometers)"

True, but there is there. If you connect the dots from 1831 to 2005, you will see an about 2-3 degree westward angle from vertical , which is very close to the difference you get when (let's say) when you trying to superimpose an 1863 map to an aerial photo of Gettysburg, both with N on top, based on the main roads. It is ok, but it is somewhat irritating when trying to find exact placements of things back then now, based on those maps. See the example below: Both Emmittsburg Rd and Taneytown road are slightly off by those few degrees (more obvious in the bottom of the picture.) In real scale, if you try to find something it might be a good 8-10 feet away from where it was supposed to be...

 

[RobertP]

True, but there is there. If you connect the dots from 1831 to 2005, you will see an about 2-3 degree westward angle from vertical , which is very close to the difference you get when (let's say) when you trying to superimpose an 1863 map to an aerial photo of Gettysburg, both with N on top, based on the main roads. It is ok, but it is somewhat irritating when trying to find exact placements of things back then now, based on those maps. See the example below: Both Emmittsburg Rd and Taneytown road are slightly off by those few degrees (more obvious in the bottom of the picture.) In real scale, if you try to find something it might be a good 8-10 feet away from where it was supposed to be...

The early maps likely were oriented to magnetic North by using only a compass rather than determining true North (the actual North Pole) as is done in all modern mapping. As we know magnetic North changes over time, true North does not and the variable between the two is the magnetic declination. There are historical calculators available on line; a quick look shows that the current declination at Gettysburg is about -11 deg., in 1860 it was -4 deg. What that means is that a map made in the 1860's with using the compass needle as North is 4 degrees off from where true North is as shown on your new map. That likely accounts for the difference you are seeing.

 

[DixieRifles]

Oh.

 

[FarawayFriend]

Here is a link to a map the great Jedediah Hotchkiss had prepared for General R. E. Lee. I have snipped the part covering Salem Church. Maybe that will help you locate your ancestors regiment.
http://www.davidrumsey.com/luna/ser...hing&thumbnailViewUrlKey=link.view.search.url

 

[RobertP]

Here is a link to a map the great Jedediah Hotchiss prepared for General R. E. Lee. I have snipped the part covering Salem Church. Maybe that will help you locate your ancestors regiment.
http://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~26870~1100169:Chancellorsville,-Salem-Church,-Fre?showTipAdvancedSearch=false&showShareIIIFLink=true&showTip=false&helpUrl=http://doc.lunaimaging.com/display/V72D/LUNA+Viewer#LUNAViewer-LUNAViewer&title=Search+Results:+List_No+equal+to+'1780.041'&fullTextSearchChecked=&advancedSearchUrl=http://doc.lunaimaging.com/display/V72D/Searching#Searching-Searching&thumbnailViewUrlKey=link.view.search.url

View attachment 123187

Hotchiss could make beautiful maps couldn't he! One of the most interesting characters of the War.

 

[Podad]

Side note:
One of my ancestors was there bottom center where it shows Wofford's line. He was with the 24th Ga one of Gen. W. T. Wofford's regiments. From an account I read written by Col CC Sanders of the 24th Ga the church building and grounds served as a hospital and was the scene of horrific suffering.

 

[rpkennedy]

Side note:
One of my ancestors was there bottom center where it shows Wofford's line. He was with the 24th Ga one of Gen. W. T. Wofford's regiments. From an account I read written by Col CC Sanders of the 24th Ga the church building and grounds served as a hospital and was the scene of horrific suffering.

Three of mine were fighting in the same regiment as @Pvt.Shattuck's.

Ryan

 

[redbob]

Records from the 11th Alabama (Wilcox's Brigade) would indicate that the church was located about where the school house is placed. Also, it shows that the 16th New York attacked the right of the Confederate line.

 

[Pvt.Shattuck]

Here is a link to a map the great Jedediah Hotchkiss had prepared for General R. E. Lee. I have snipped the part covering Salem Church. Maybe that will help you locate your ancestors regiment.
http://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~26870~1100169:Chancellorsville,-Salem-Church,-Fre?showTipAdvancedSearch=false&showShareIIIFLink=true&showTip=false&helpUrl=http://doc.lunaimaging.com/display/V72D/LUNA+Viewer#LUNAViewer-LUNAViewer&title=Search+Results:+List_No+equal+to+'1780.041'&fullTextSearchChecked=&advancedSearchUrl=http://doc.lunaimaging.com/display/V72D/Searching#Searching-Searching&thumbnailViewUrlKey=link.view.search.url

View attachment 123187

This is awesome. It looks like the OR was right- no one on their right flank, not a good position to be in.

 

[DixieRifles]

Maybe that will help you locate your ancestors regiment.

And suddenly there is a 90-degree corner in the Union line. Now I can see how a regiment could have been out-flanked and risked capture.

 

[RobertP]

This is awesome. It looks like the OR was right- no one on their right flank, not a good position to be in.

I started re-reading this book, Chancellorsville's Forgotten Front, from 2013 and . . .

saw this map of the Salem Church battle. Maybe you haven't seen it.

About the 16th NY the author writes:

 

[AndyHall]

Great map by Hal Jepersen.

 

[Podad]

@lelliott19 are you reading this thread?

 

[Pvt.Shattuck]

I started re-reading this book, Chancellorsville's Forgotten Front, from 2013 and . . .
View attachment 123863
saw this map of the Salem Church battle. Maybe you haven't seen it.

View attachment 123864
About the 16th NY the author writes:

View attachment 123865

I had never seen this before. Thanks for the new source.