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Room Home page |
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| How to download UK Census data
from CASWEB for use with MapInfo |
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| The CASWEB service is available to higher and further education
users and enables registered users to download census data. The data can
be used in a GIS, such as MapInfo which is available in the Map Room. |
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| What is CASWEB? |
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| Casweb is a web interface to statistics and related information from the
United Kingdom Census of Population 2001, 1991 and 1981 (earlier data will
be available in the future). These large and complex datasets comprise aggregate
counts of persons and households for various geographical units. For more
information about these datasets refer to the CDU
Census Knowledge Base. |
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| To use download and use data
from CASWEB you must be a registered user |
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| To register forCASWEB (University of Oxford users
only): |
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Click the Registration link under New Users |
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Click the Login via ATHENS button, then select
the Alternative Login link on the ATHENS login page. You have
to select your institution (University of Oxford) which will redirect
you to the Oxford login page. Log in using your Oxford Single Sign-On
(SSO) username ( eg abcd1234) and password (it's the same one you
use to access your Herald or weblearn account) |
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Fill in the online registration form. You will be asked
to view and agree to conditions of use for each of the datasets available.
Do this for each of the datasets you wish to use. You will then receive
an e-mail, containing a link which you must follow to complete your
registration. |
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| *The CRS also has guidance on citing data sources in your research work. |
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| You will also be able to download a wide range of administrative, census,
health authority and other boundary datasets from UKBorders
- separate registration is not required. |
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| Downloading data from CASWEB is a three-step process: |
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Select the geographic area and the output geography
(district, ward, ED) |
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Select the data required |
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Output the data (as a table for use in a database
or spreadsheet, or as mappable data for use in MapInfo) |
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If you have not used MapInfo, have a look at the Easy
Guide for New Users which takes you through the basics of MapInfo.
This guide explains the steps to follow in MapInfo and you will be able
to create a map even if you have not used MapInfo before, but to make
full use of the software you should have a look at the guide.
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| The following steps show how
to download selected 1991 country of birth data for Oxfordshire
at ward level and map the results in MapInfo. You can apply the same methods
to your own requirements. At present (August 2005) 2001 data does not include boundaries, but these are available in the Map Room. |
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| Part 1. Selecting the geographic area and output geography |
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| This is the first step. If you have not already logged in to CASWEB, do
so now. You will then be at step 1 of 3 Define study area. |
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| 1. Click the link to Great Britain 1991 SAS and
LBS. You will then see the Select Ouptut
Areas page. At the top you will see a dropdown list
where you can choose List view or Map view (The Map view option displays
a map which can be used to select areas. This requires a plug-in which may
have to be downloaded first). |
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2. In the Counties/Regions list, click England
to select it. Then click the Select Counties/Regions...
button.
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| 3. Scroll down the list and select Oxfordshire. Scroll back up
and click the Select Output Level... button.
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| 4. In the lower part of the Select Output Areas window which is now displayed,
click the Ward option and then click the Select
Data... button. |
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| 5. Make sure that the LBS level is selected (Local Base
Statistics data is for wards and larger areas, Small Area
Statistics data is for Enumeration District (ED) level). |
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| 6. In the Table List, select
07 Country of Birth. In the Variable
List frame (Frame C) you will see that the Zone ID and Zone
Name have been selected already and are required to map the data. You
can add Area if you wish (be careful not to lose the other two when
you click Area - hold down the shift key and select all three), but MapInfo
knows the area of objects so it is not needed. |
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| 7. Click the Select Variables button. You
will now see a table of all the variables available. (If you selected the
wrong table, click the Click here to select another table link to
go back and try again. |
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| 8. Note the warning "This table contains counts of persons"
- these are actual numbers, not percentages, so for meaningful comparisons
between wards we will need to create a "percentage of the total"
value, which we can do later in MapInfo. If you are just downloading the
data for use in a database or spreadsheet, you can do this later using a
formula. |
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| 9. If you click a checkbox in the grey area of a column or row,
it will select the entire column or row respectively. It is better
to check individual values so you do not end up with more data than you
need! |
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| 10. We need the total persons first, so click checkbox 1 (Total
persons, all countries of birth). We will also map by total persons
born in the UK, Africa and Caribbean, so check the
checkboxes 10, 58 and 103 as well. |
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| 11. Click the Add variables to Data Selection
button. The variables will appear in the Variable List. |
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| 12. You will see that only the ID numbers of the data variables have appeared,
so you will need to note down the actual variable names, or change the numbers
to names (this will be fixed in a future version of CASWEB). To change a
number to a descriptive name, start with variable 107001 (this means table
07, varable 1- total pop). Click the variable in the Variable
List, then click the Rename button. |
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| 13. A dialog box will appear where you can change the name, in this case
change it to Total_Pop for example (note that you have to use an
underscore <Shift+hyphen> to link words. Spaces are not allowed).
Repeat with the other variables. |
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| 14. Make sure all variables are highlighted (click
Select All if they are not), then click Get
Data. After a short while, a preview of the first few cells will
appear so you can check it is OK. If you don't see a preview it is because
the Preview Data checkbox on the previous page
was not checked. (This is not necessary to get the data). |
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| 15. In the Data Download Options page which
appears next, click Mappable output format
and select MapInfo as the Type.
Change generalization to none to
maintain high-resolution boundaries. Now Enter a filename (such as oxon_cob)
and click Execute Query... |
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| 16. Wait for the file to be created. When the Download
Data File window appears, click the button with your filename and
save the file in your own user folder. It will download as a self-extracting
zipped file. See the Easy
Guide for New Users for more information on creating users folders in
the Map Room. If you are working elsewhere, save the file in a suitable
folder. |
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| 17. The last step here is to unzip the file. Open Explorer
and find your downloaded file. Double-click the file to extract the contents.
You will see two new files, one with a .mid extension and another
with a .mif extension. These are the MapInfo files. Close Explorer. |
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| That's the first part done! You can now display
the data in MapInfo. |
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| Part 2. Displaying the data in MapInfo |
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| The next stage is to import the data into MapInfo so it can be displayed.
The data only has to be imported once - after that the data is in MapInfo's
internal format and can be displayed immediately. |
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| 1. Start MapInfo. |
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| 2. If the Quick Start dialog appears, close it. |
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| 3. On the menu bar, click Table, then Import...
Select the file and click Open. You
will then be asked for a filename to save the imported table as - use the
same name (which will already be shown in the Filename box) and click OK.
MapInfo will now import the file, which may take a short while. |
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| 4. Open the table by clicking the File menu
and then Open Table (or click the Open Table
button). Find your file and open it. |
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| 5. You will see part of the boundary map in a window. Maximise the window,
then right-click with the mouse over the map and select View
Entire Layer from the pop-up menu. Choose your table from the list
and click OK. You will now see the whole of Oxfordshire with ward boundaries. |
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| 6. To display the data requires three steps. To start, click the Map
menu and then Create Thematic Map. For this
example we will map the numbers of persons born in Africa. |
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7. In the Create Thematic Map- Step 1of 3 dialog,
choose Ranges as the type, then click
Next.
In the Step 2 of 3 dialog, choose Africa
in the Field list and click
Next. A preview of the data legend will be displayed. Click
OK to display a map and legend. |
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| Remember that the data shown at the moment is actual counts - for a
more meaningful display we need percentages of the total. |
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| 8. To show percentage values, first remove the thematic layer by right-clicking
on the map, then clicking Layer Control in
the pop-up menu. You will see a layer in the list called "Ranges
by... " above the base map layer. click this layer to highlight
it, then click the Remove button. Click OK.
You will be asked if you want to save to a Workspace - click Discard
for now. |
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| 9. You will now see just the outline map again. Create a thematic layer
again by clicking the Map menu, then Create
Thematic map again. Choose Ranges again and go to step 2,
but this time, in the Field list choose Expression. This will display
the Type an expression dialog. |
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10. What we need to calculate is the percentage of the total, so to do
this with those born in Africa, the expression would be:
(Africa/Total_Pop) * 100
You could enter this directly in the Type an expression box, but
if you cannot remember the field (column) names, use the lists at the
side to select them. You can in fact build the entire expression from
these, like this:
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Click Operator
and choose the pair of brackets () - they are jst above AND in the
list. You will see that the cursor is placed in between the brackets.
Leave the cursor where it is |
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Click Columns and select
Africa |
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Click Operator again and
select the divide by operator / |
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Click Columns and select
Total_Pop |
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Now click outside the right-hand bracket and
select * from the Operators list |
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Type 100 |
Click OK to return to step
2 of 3. If you have made a mistake in syntax, go back and correct
it.
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| 11. Click Next to go to step
3 of 3, then click OK again to display
the data. |
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| This is a very basic guide to using the data in MapInfo. To make full
use of the capabilities of MapInfo, including using map data to enhance
the map, see the user
guides for more details. |
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Map Room
Bodleian Library 2008
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