GEOGRAPHIC AREA CHECK ON HISTORICAL CENSUS DIVISIONS
As census areas change over time, it is imperative to ensure that the area for the table selected, in this case the 1861 NS Table XII - Ship Building and Fisheries matches our 1996 Census boundaries.
You will also have to check on the geographical area of the historical data table as your ArcCanada cd96.shp file may work with your downloaded historical data exactly, or you may have to alter the GEOCODE (the cd numbers such as 1203 which indicates NS Digby County) to match those in the ArcCanada cd96.shp file.
NOTE: StatCan is aware of the disconnects in the CD geocode in their historical census files compared to today's CD files and may soon be updating the historical datasets to allow use without the extra work. This is due to the fact that Census Divisions are living entities and have their own historical geographic area life as well.
In the meantime, this aspect of the historical data will have to be checked and if found to be inaccurate, the file will require data manipulation in a spreadsheet to match with ArcCanada 1996 CD or your CanMap EA codes located on the ESRI NS Local Data CD, that some ArcView schools purchased under the IEI project. However the EA codes are only for Nova Scotia, and as such other Maritime, Atlantic, Upper or Lower Canada type historic data will have to be matched at the CD level only.
Geographic Area Check Process
Step One ( if not already done as part of the data download)
To get this information, first observe in the previous image above, the first Option on the OUTPUT Format Reduce or Sort Geo List. Click on Reduce or Sort Geo List and you will get the geographical areas associated with the data table using a GEOCODE or Census Division as show below.
We will discover that the 1861 NS Table XII - Ship Building and Fisheries does have current Census Division codes for Nova Scotia indicated by the four digit number starting with the Nova Scotia provincial code 12. Yet we also discover that the current 1996 CD codes indicate that 1203 reflects Digby County in Nova Scotia while as you can see above, Digby County is using an outdated historical code 1204.
If the codes match today's 96CD.shp file Geocodes, then no further work in required and you may skip all this and return to using the data in ArcView instructions.
Print this page for future reference as you will need it to redo the geocodes after downloading the table data
Census Division GeoCode Update Procedure
1. Open Excel or your spreadsheet program.
2. Load in the dbf file. In our sample it is 1861_tableXII.dbf
3. Locate your page that you printed previously.
You see that the first line of your data is from Annapolis County (1203) according to the HISTORICAL Census Division, followed by the second line of data from Antigonish County (1214) and so on.
4. Open your ArcView program and load in the cd96.shp file. This file is located on your ArcCanada CD, as well as in your LRT GIS Support CD #1 (Nova Scotia schools only )
5. Open the associated table for cd96.shp by clicking on the Open Theme Table.
6. Now sort the CD field by clicking first on the field name, and then on the Sort Ascending icon as shown below.
7. Scroll down until you find the NS section codes starting with 1201(Shelburne County).
8. Now we are ready to switch back and forth from the ArcView cd96.shp data table, Our downloaded ESTAT table XII open in Excel, and our printed page with the geographic areas by line we printed from ESTAT.
Line one of the Table XII open in Excel indicates code 1203 or Annapolis County as shown on our print out from ESTAT.
What does the CD96.shp table indicate for Annapolis County in 1996 as shown below ?
In the 1996 census, Annapolis County is now 1205. So in your Excel program, edit the first line geocode from 1203 to 1205.
9. Continue with each line in the EXCEL table changing line two geocode of 1214 for Antigonish County to the ARCVIEW 1996 code of "SURPRISE" ...1214.
10. Then line three code in the EXCEL table from the 1218 for Cape Breton County to to the ARCVIEW 1996 code of 1217. And so on, until all lines have been done.
|You will discover that Halifax City is included in the list
of Counties. As Halifax City is a part of Halifax County, I suggest that
we leave that code blank and add the data for Halifax City to the data
Once you complete the Geocode corrections, then amend the Halifax County line to include the Halifax City data for each field.
Delete the Halifax City data as you work, to avoid errors.
11. Once you have all the data moved into the Halifax County fields, then delete the old Halifax City line altogether in the database as shown below.
12. Now save your corrected Excel datafile with the same name as a .dbf file so that you can now match the codes in ArcView table joins successfully.
SUCCESS...and it didn't take from 1861 to 1996 to do it either !!!
It may seem complicated at first, but really all you are doing is altering yesterday's codes to today's.
You use Excel to do it, but you use ArcView to give you the 1996 codes for matching and the printout from ESTAT's file to keep the line numbers coordinated in order as you work on the spreadsheet file..
The good news is that for our Nova Scotia Shipping exercise, all the three tables are in the same order, so we can cut and paste...with the exception of Halifax City. This speeds up the process and I suggest that you do all your data corrections at the same sitting so as to speed up the effort.
However once you have them done once, and the next step converting them to a shape file completed, you will only have to do it once as you can create many themes from the one ESTAT table.