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Data Cleaning



TGIS has been using the methods described below for more than 11 years in serving South African Municipalities. We have cleaned the data for 46 Municipalities and currently maintain the data in 31 Municipalities.

There are two approaches to cadastral data, the first is we will supply the data to the client in an easier to use and understand format than it is available at its source, no cleaning or verification takes place, the data is compiled and delivered, the data as well as a discrepancy report will be delivered, the client may then request the corrections of errors at a later stage. The second approach will involve TGIS utilising its intellectual property and methodology to not only supply the data but to also verify and correct the errors. This method is the recommended one as you can be assured that the data is clean and reliable, where errors have been rectified.   

At TGIS we have worked, adapted, cleaned and delivered all of the datasets to a variety of clients. In our experience we have found some clients to posses outdated and incorrectly cleaned datasets which they assume are correct, which can lead to a variety of errors in decision making. We will gladly verify your data’s quality. Please contact us on +27 12 991 3624 or

1.1 Standard Methodology

This section summarises our standard approach:

  1. Acquire the SG digital parcel data set
  2. Acquire all scanned diagrams of Farms, Holdings, Erven, and General Plans.
  3. Link these to the digital parcel data set
  4. Check for missing or incorrect polygons and correct these
  5. Acquire the deeds data
  6. Link this to the digital parcel data set
  7. Identify gaps and errors and correct these
  8. Link to the Client financial or other data sets and identify problems in the client data and the digital parcel data set

1.2 Data Compilation and Delivery Only

The following addresses data compilation and delivery, there are no guarantees as to data quality and accuracy as it is merely presented as held at third party sources. This option is available for low capacity and limited budget clients. A cadastral dataset is necessary to administer land, but a cleaned data set is recommended. If the client gets the data supplied agreement can be reached to verify the data over a period of time, this can be included into the maintenance of the data. Some steps in our standard methodology are excluded.

1.3 Data Cleaning and Verification

This section is for cases where the client has specified the cleaning of data as pre-requisite to the supply of GIS data or the client requires quality data. This is the recommended approach as the data is more accurate and hence more reliable. We recommend having your data cleaned and verified, it is more costly but for effective governance one must have accurate information to form the base for decision making.

1.4 Maintenance of Data

A maintenance contract can be included in supplied data and cleaned data projects. The pricing related to data maintenance will be determined during the project, it is subject to the amount of properties and data entities to be monitored and maintained.

Data Supplied Maintenance:   As this GIS contains only unverified information, maintenance can be done by bringing it on par with cleansed data, evenly spread over a period of three years on the basis of a monthly fee. This will eliminate an immediate large capital outlay and will become an operating expense. Over and above the verification of parcel (Cadastral) data, ownership movements will be updated every month.

Data Cleaned Maintenance:   This GIS already contains verified information and requires only updating of parcels (Cadastral) and deeds information. The map information will be updated every three months whilst the ownership movement will take place every month. The maintenance period will also be for three years but the fee will be substantially less than that of data supply where verification still needs to be done. This will be an operating expense for the client.




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