Importing postal codes

If you have a CSV or TSV file of postal code data, you can load this into MapIt directly. We’ll assume you have installed MapIt as per the installation instructions and that you have a CSV file containing postal codes in the first column, latitude in the third column, and longitude in the fourth column, and that it has a header row.

There is an import script that will look at the CSV file and create entries from it. We’ll call it as follows:

./manage.py mapit_import_postal_codes \
    --coord-field-lat 3 \
    --header-row        \
    /tmp/postal-codes.csv

That’s all there is to it in this case, and it will update you on progress every 1,000 imported postal codes.

Other options this import script have are:

• --code-field N – The CSV column containing the postal code (defaults to 1)
• --coord-field-lon N – The CSV column containing the longitude (or X) co-ordinate (defaults to latitude column + 1)
• --no-location – Set if you don’t have the location of the postal codes, only a list (still useful for checking validity of postal codes)
• --srid SRID – Set to the SRID of the co-ordinates, if not WGS-84 (4326)
• --strip – Set to strip spaces from the postal code before importing
• --tabs – Set if the file uses tabs as a separator (TSV) rather than commas

So to import a TSV file, using the OSGB co-ordinate system (which uses eastings and northings instead of longitude and latitude), with the easting in column 5, the northing in column 7, and the postal code in column 10, with no header row, you would do:

./manage.py mapit_import_postal_codes \
    --code-field 10     \
    --coord-field-lon 5 \
    --coord-field-lat 7 \
    --srid 27700        \
    --tabs              \
    /tmp/postal-codes.csv

Note: If you get the error django.db.utils.DatabaseError: invalid byte sequence for encoding "UTF8": 0x00 at some point, you are probably being bitten by this bug - the solution is to add standard_conforming_strings = off to your postgresql.conf file, or to apply the patch in that ticket.