Newberry Atlas of Historical County Boundaries Shapefiles in QGIS?

[Sorenroy]

Hello all. After seeing the thread about how to make maps in QGIS I decided to finally go and download the program for myself. Along with it, I also downloaded the shapefiles for my home state (NC) from the Atlas of Historical County Boundaries. The only problem is that I really have no clue how to use it. I've gotten far enough to understand that the shape that shows up in the current map is from the Attribute Table, but I can't figure out either how to hide the parts of the table I do not want or how to just remove them all together.

[cinyc]

What are you trying to do?

If you're trying to get a map as of a certain date, do the following:

Hit the Connecticut Avenue Monopoly card icon, AKA Open Attribute Table.

On that dialog, hit the icon that looks like a funnel, a.k.a. Select features using form (or hit CTRL-F).

To make a map of counties as of January 1, 1776, scroll down to START_N. Type in 17760101. In the drop-down menu immediately to the right, select "Less Than or equal to". Enter the same date (17760101) in END_N and select "Greater Than or equal to".

Hit Select Features.

I don't have my editing toolbar enabled right now, so what I'd do is hit "Edit" on the top menu, then "Copy Features" (Or hit CTRL-C), then "Paste Features--> As a temporary scratch layer" and give it a name, "1776 NC Counties" or whatever. You can save it as a vector layer now, too, if you want something permanent. If your edit features toolbar is active, there's probably a shortcut. I don't know it off the top of my head.

You should now have a map of the counties as of 1776 in the new layer. You might need to deselect the NC Historical Counties layer to see it (uncheck the box next to it).

[cinyc]

Neat database, by the way. Using the method described above, I made this map showing the state and county boundaries as of September 3, 1783:



Edited to add: I guess Vermont technically wasn't a state then, though. It was the Republic of Vermont. And Maine was part of Massachusetts.

[cinyc]

With a little bit of auto-coloring, you can make your map and legend look like this, instead:



The next installment on the QGIS How To will be how to auto-color and change styles.

[Sorenroy]

Thanks for the help, the Monopoly reference really helped! I would like to put together a county map for every census, at least that's the goal right now.

[cinyc]

Thanks for the help, the Monopoly reference really helped! I would like to put together a county map for every census, at least that's the goal right now.

You can do that by changing the START_N and END_N to the relevant census date for each decade. It wasn’t always April 1. I’d save the new layers as a vector file each time, instead of in memory, then.

I think the START_N and END_N dates are in YYYYMMDD format, but you should check the Readme file that came with the Newberry package.  

You can thank jimrtex for the monopoly reference.

[jimrtex]

Hello all. After seeing the thread about how to make maps in QGIS I decided to finally go and download the program for myself. Along with it, I also downloaded the shapefiles for my home state (NC) from the Atlas of Historical County Boundaries. The only problem is that I really have no clue how to use it. I've gotten far enough to understand that the shape that shows up in the current map is from the Attribute Table, but I can't figure out either how to hide the parts of the table I do not want or how to just remove them all together.

What are you trying to do?  You might do better at National Historical Geographic Information System, which has historical census data, plus the shapefiles that go with it.

.shp files have the vertices of polygons that define areal features, in this case counties. Other .shp files can have vertices of linear features (polylines) that might be used for highways or stream courses. And other .shp files may have single points that might be used for locations of courthouses. The .dbf file has attributes associated with the features in the .shp file.

There is a simple 1-to-1 relationship between the two files. The first row in the dbf file corresponds to the first entry in the .shp file and so on. When you open a .shp file in QGIS, it looks for other files with the same name (.dbf, .shx, and .prj). The .shx file is an index file for the .shp file. Because polygons can have variable numbers of vertices, the entries in the .shp file are variable length, that makes access by a computer slower (it would equivalent to finding chapters in a book by scanning page by page through the book). The .shx file has pointers into the .shp file for each feature. The .prj file provides information about the coordinates.

If someone sent you anonymous.shp file, you might eventually be able to figure out that it has some latitude longitude vertices that are in North Carolina, and eventually that they represent counties. If someone sent you anonymous.dbf you could figure out that it had information about NC counties, and probably historical changes, since it includes legal citations, and what happened.

What is unusual about this .shp file is that it has multiple representations of each county, corresponding to when boundaries have changed. The number varies based on the times that the county boundaries have been changed. There are 18 versions of Bladen.

The default rendering for a .shp file is a single color. Features are apparently drawn in the order stored in the .shp file, which is historical order. If you had a much slower computer, it might be possible to see the counties changing. So what you see is the latest version of the the counties. Tennessee is shown as the last version prior to cession, after which they were no longer North Carolina counties.

Right click on the layer, Select Properties -> Style, and change the color to a very deep saturated color (blue works nice). Move the transparency way over to the right (90%). Click on Apply/OK. What you have done is to make the counties largely transparent. It is like you had stacks of blue-colored glass. Where there are several sheets it looks dark blue. Where there is only one or two sheets it is a paler blue (in Tennessee there were few versions before session). The three counties with Guilford in the middle indicate that there have been few changes.

Right click on the layer, Select Properties -> Style, and click on the little color box. Press the down arrow at the far right of the Fill box, and you will see a color selector. At the very top check Transparent Fill. Move the transparency slider back to 0%. Apply/OK. Now you can see all the county boundaries ever used in North Carolina.

Cinyc was correct in how to extract the counties for a certain time. I probably would have used Select by Expression to do the same. When you go back in to select another expression, previous expressions are available at the very bottom of the list on the right.

If you wanted to be able to do this on the fly, you could add additional columns indicating which counties were active at a certain date. You could also include county populations, and display directly without extracting separate shapefiles.

[jimrtex]

Thanks for the help, the Monopoly reference really helped! I would like to put together a county map for every census, at least that's the goal right now.

I would use National Historical Geographic Information System which has both the Census Data and the corresponding shapefiles.

There is likely a closer match with how the census was actually conducted (e.g. the legislature might have created a county on a certain date, but it might not have been organized, and whoever took the census might have realized it was a new county).

Just show you know, North Carolina entered the Union on November 11, 1789, and ceded Tennessee on April 1, 1790. The 1790 Census only included North Carolina. The census for Tennessee (Territory South of the River Ohio) was conducted in 1791.