Chapter 7 Gecodes
Using names as identifiers can easily lead to confusion over spelling and transliterations as well as alternative and duplicate names.
As unique identifiers, P-Codes overcome the challenges of linking datasets and confirming locations.
We recommend using Gecodes and Names from OCHA’s Common Operational Datasets: https://data.humdata.org/dashboards/cod?ext_geodata=1&q=&ext_page_size=25
7.1 A brief example of the problem:
The geographic variables of the choices section of the xlsform typically look like this
| list_name | name | label |
|---|---|---|
| cod_lga | 1 | ASKIRA/UBA |
| cod_lga | 2 | BAYO |
| cod_lga | 3 | CHIBOK |
| cod_lga | 4 | KALABAGE |
The geographic variables in corresponding GIS dataset look like this:
| Shape | admin2Pcode | admin2RefName |
|---|---|---|
| Polygon | NG008002 | Askira/Uba |
| Polygon | NG008004 | Bayo |
| Polygon | NG008006 | Chibok |
| Polygon | NG008015 | Kala/Balge |
Unfortunately, if we tried to merge the dataset and the GIS file by the name of the area, we would first have to fix the capitalization and punctuation of the names.
To avoid unnecessary work, we recommend putting in the Pcode in the name column of the xlsform:
| list_name | name | label |
|---|---|---|
| cod_lga | NG008002 | ASKIRA/UBA |
| cod_lga | NG008004 | BAYO |
| cod_lga | NG008006 | CHIBOK |
| cod_lga | NG008015 | KALABAGE |
With a common, simple variable to merge both datasets, mapping and data processing will be much easier!
7.2 Where to find Pcodes
Geographic data can be found https://data.humdata.org/dashboards/cod?ext_geodata=1&q=&ext_page_size=25 and searching for the appropriate country.
We recommend using the codes from the admin1Pcode and admin2Pcode columns in the name column of the xlsform. Using the admin1RefName and admin2RefName
7.3 Example data set of the data collection sheet for Nigeria:
7.4 2 caveats
In some countries, the boundaries in the CODS might not correspond with the latest boundaries used by the country. In this case, special development of a GIS boundary file and codes will need to be developed.
Inserting the relevant pcodes in the name column will probably require some vlookup . This might be relatively straightforward when only replacing codes at the admin1 and admin2 level, however things might get more complicated and difficult if cascading columns and the choice_filter option is used at the adm3, adm4 level.