How to Use the Cadastral Maps

Secondary maps#

If you open the NW-cadastral.db project, PlanetGIS will show the following:

PlanetGIS is looking for SA-administrative.db in the parent folder. If you don't care about the administrative boundaries (and background images), you can click No and keep using the cadastral map without it. You can also, at this point, download the administrative map and extract it to that location. You would have to either click Yes and locate it, or (a quicker way would be to) click No in order to carry on, close PlanetGIS and reopen the map so that it will open the administrative map automatically.

After you click No (or No to All) to a File not found prompt, Planet will also ask you if you want to remove all references to the omitted file. You can select No (or No to All) until you have decided whether or not you want to install the additional maps.

Changing a secondary map's location#

If you prefer a different location for the administrative map, for example in the same folder as the cadastral map, then once you have placed it there, click Yes and go through the process to locate the SA-administrative.db file.

In the following example, we placed all the files from inside the NW folder (in the NW-cadastral.zip) on our hard drive in a folder named NW Cadastral 2024, so that there isn't a NW subfolder, since we'll only be working with one province. We then extracted the files from SA-Administrative.zip into the same folder, as follows:

After opening the NW-cadastral.db project, we selected Yes to the prompt to locate the missing SA-administrative.db, which gives the following where we will select the administrative map in its new location:

Planet will now open the administrative map and remember its changed location the next time you open NW-cadastral.db.

Web tiles#

The SA administrative map includes a link to OpenStreetMap's (OSM) tile server. The cadastral maps include a display that references this server, as well as other tile servers (links also in the administrative map), like Google Maps and Bing. The OSM web tiles make an excellent backdrop for the cadastral maps:

There are several downsides to using images from a tile server:

• You cannot use it in conjunction with other background images, e.g., OSM with Google Satellite. Google has a hybrid option that partly addresses this by combining images with roads and other features.
• The images require an Internet connection and can be slow to use. As the images are received, Planet has to redraw the map every few seconds to update it. Planet does store each image on your hard drive (in the .tiles file), so that repeated use in the same area (and at roughly the same scale) becomes quick.
• When the tile images contain text, the outlines of features that are overlaid on top obscures parts of the text.
• You cannot use filled area features (polygons with a style containing a fill), but it is possible to make fills semi-transparent or use hatch fills.
• You cannot select a feature shown in a raster image.

Notice how the boundary features partially obscure text from the background images in the above example.

Vector street map#

The SA-OpenStreetMap.db project contains OSM data imported into PlanetGIS as regular features. The advantages to using this map are:

• You can choose layers from this map relevant to your projects.
• You can change the styles (colours, icons, etc.) for each feature class (layer).
• You can identify each feature by clicking on it and view attribute information.
• You can make modifications to a feature, like moving it to a better location or deleting it.
• You can copy one or more features to your own project.
• You don't need an Internet connection to use the data.

In the above example, a section of road has been identified (clicked on) and the Attributes tab activated. Notice that useful information is attached to features in the OSM data, for example speed limits on roads.

Missing locator plug-in#

Figure 11, above, shows the contents of a zip file containing the combined cadastral maps. You will notice a DLL file, ParcelFind.dll. Each of the provincial sub-folders will also contain the same file. If that file is not present in the folders containing your cadastral maps, as extracted from the zip(s), you will not see the parcel locator in PlanetGIS, after opening the maps. You must ensure that ParcelFind.dll is extracted to the destination folders, along with each project database (.db) file.

Using the land parcel locator#

Administrative region

Selecting an administrative reqion is optional, but helpful to narrow further selections. In Figure 12, the thinner purple boundaries are administrative regions. The northern 4 provinces and KZN use a 1 × 1 degree grid system which has squiggly boundaries because they follow the boundaries of original (parent) farms. In these provinces they are called registration divisions. The other 4 provinces have administrative districts, which are usually roughly equivalent to magisterial districts as they were at some point in history. These boundaries have no modern use other than in the coding system used by the Surveyor General for each land parcel.

Provinces with a grid system (e.g., North West in the example above) will have each grid block named with a two letter code (IM, IN, IO, etc., in the example) that also appears in the registered name of each parent farm. The names of the administrative regions in the other provinces generally correspond to the name of the largest town, at least as it was named at some point in history.

Another broad term for these are major regions.

If you are not sure what to select, leave the selection empty or choose Any. You will then have a much larger list of Townships or Parent farms, possibly with duplicate names, to choose from. If you do select a region, Planet will select it and zoom to it immediately.

Parcel type

• Erf / holding: Erf is the technical term for an urban land parcel and holding refers to small holdings or agricultural holdings (the term varies depending on the province, and some provinces don't have them at all). Both are treated similarly by the SG.
• Farm portion: Outside of urban areas, all land parcels are farm portions which are usually subdivisions of original (technically referred to as parent) farms.
• Parent farm: Original farm boundaries; aggregate boundaries of farm portions.

Minor regions

The next level of division in the cadastral boundaries is even more complicated in terms of terminology. This level is not applicable to farms or farm portions. Farms are uniquely numbered within their major / administrative regions, and farm portions are numbered similarly to erf / holding subdivisions.

The following provinces have townships or holdings as their second-level divisions (minor regions):

• Free State
• Gauteng
• KwaZulu-Natal
• Limpopo
• Mpumalanga
• North West

The other provinces refer to these as allotment areas and do not have holdings:

• Eastern Cape
• Northern Cape
• Western Cape

The data that is provided by the SG has this level consistently named allotment townships, and in all the PlanetGIS projects, we chose to name this layer (feature class) Allotment areas. In the parcel locator, they are simply referred to as townships, even though technically, a township has a more precise meaning.

These minor regions should be interpreted simply as named groupings of land parcels which are sequentially numbered (usually starting at 1) and unique within the grouping. They often correspond to suburbs when all (or most) of a suburb's extensions are included. (There are often multiple boundaries—one for each extension—with the same name and code. The parcel locator will select them all, as if they are parts of a single multi-part boundary.)

The boundaries of minor regions / allotment areas in PlanetGIS are shown with a thick mustard-yellow line (which you can change as required), while the boundaries of erven are the same colour but much thinner. Holdings have a thin dark-purple line style. Once you select a township (allotment area), PlanetGIS will select it and zoom to it. The northern provinces, especially Gauteng, do not always have polygons for an allotment area, in which case PlanetGIS will zoom to a centroid generated from all the erven/holdings in that allotment area.

Parks, which are technically erven with a designation of public open space, are shown as a separate layer (feature class) with green boundaries and a green diagonal hatch fill. The parcel locator includes the Parks feature class when searching for an erf number.

Locating an erf

Township

If you have Erf / holding selected as the parcel type, you need to select a Township. The dropdown button () will list all townships (allotment areas) in the selected administrative region, or if none/Any selected, all townships in the province. If you enter a few letters, this list will be reduced to names starting with those letters. You must select an item in the list because the locator uses the code inside [square brackets] to build the SG key that is used to locate the parcel.

Once you select a name in the township list, PlanetGIS will select and zoom to the township (allotment area / minor region) boundary. In some cases, such a boundary doesn't exist in the database and PlanetGIS will zoom to a centroid of all its parcels instead.

Duplicate names are common, especially if the list hasn't been restricted to an administrative region. The map location / selection will assist in determining if you have selected the correct name, and take note of the [code] to help with further searches.

Erf number

Once you start entering digits in the erf number input box, the locator will build an SG Key from it. If a land parcel with that key is found, PlanetGIS will select and zoom to it on the map. If not found, you will see (not found) next to the SG Key input box.

Erf portions

If the erf number you entered resulted in the locator finding multiple subdivisions, you will see an additional dropdown box with all the subdivisions, e.g.:

In some cases there will be only one portion (with a non-zero number), in which case the dropdown box will be shown disabled, but the SG key built with that portion number at the end, and the parcel selected on the map. The dropdown box shows the label text on the cadastral map, which can differ from the actual property code. In most cases, a remainder is actually portion 0 but shown as RE/n, where n is the erf number. It is also possible to see something like x/y/z, i.e., portion x of portion y of erf z.

Some provinces (WC, EC, NC) use a different method when subdividing erven. Each subdivided parcel gets a new sequential erf number, instead of being numbered as portion x of erf y and only the remainder becomes RE/y.

SG Key

See below for a full description of the SG Key. You can enter the key yourself (or cut-and-paste) to use the locator to find a land parcel with that key. If you enter exactly 8 characters, it will locate the minor region with that code. In order to locate an erf or farm portion, it needs exactly 21 characters.

Locating a farm portion

The legal identifier of a parent farm is a number that is unique within the administrative region. Farm names can be missing or incorrect in the cadastral database. Farm names are also often duplicated. If you enter a farm name, be aware that you may not be getting what you expect. (The map location/selection will be helpful here). Entering a farm number is more precise.

Once you have selected an item in the Farm name or no. dropdown list (so that the input box contains an item ending with a code in [square brackets], the Farm portion dropdown box will contain all portions found in the database. This dropdown box is disabled if you chose Parent farm as the parcel type.

PlanetGIS will select and zoom to a parent farm once you've selected one. In some cases, where no such boundary exists, Planet will use a centroid generated from all its farm portions. Once you select a farm portion, the land parcel will be selected and zoomed to.

The SG Key

The Surveyor General's 21 Character Key uniquely identifies all land parcels in South Africa. It consists of the following parts:

• Major region: 4 characters consisting of:
  • SG office code: 1 character:
  • T: Pretoria (Transvaal)
  • F: Free State
  • C: Cape Town
  • N: KwaZulu-Natal
  • T and N are always followed by a 0 and then the 2-letter registration division
  • C and F are followed by a 3-digit administrative region code
• Minor region: first 8 characters (major region plus 4 characters); farms will always have 0000 added to the major region
• Parcel number: 8 digits, padded with zeros to the left; erf / holding / farm number
• Portion number: 5 digits, padded with zeros to the left; portion number of an erf / holding / farm

How to get Google Earth Pro#

Google Earth must be installed on your computer. The download link for Google Earth Pro is: www.google.com/earth/about/versions/#download-pro.

KML file association#

PlanetGIS interacts with Google Earth by creating a .KML file and telling Windows to open that file. If all works like it should, Google Earth opens and adds the KML to its Temporary Places as can be seen in Figure 17.

Planet places this file in your computer's temporary files folder, which you can find by typing %temp%. The file will be named planet followed by 4 random hexadecimal digits. If you sort by Date modified you should see the most recently created KML file at the top. (See Figure 18.) You can also search for *.kml, as we've done in Figure 19.

Google Earth not loading?#

Users often report that the Google Earth link doesn't work. The most obvious reason could be that it was simply not installed. (See installation link above.).

Another reason is that, unfortunately, some applications hijack the .KML file association, or that this association has been broken or removed for some reason. Usually, re-installing Google Earth solves this. If not, you'll have to tell Windows what to do with .KML files.

To do that, you need to use File Explorer and right-click on a .KML file. (See previous section on how to locate a .KML file that PlanetGIS created when you clicked View → In Google Earth → Selected features.)

Note that in the above example, .KML files are correctly associated with Google Earth, as can be seen with the correct icon next to the file name, next to Open in the menu, and the correct first entry in the Open with menu. If this is the case, there is another reason that your Google Earth application won't open. Possibities are that the application window is stuck behind something else, on a different monitor, moved off your monitor, or the application wouldn't load due to low memory or available resources.

Once you've clicked Choose another app, click More apps, scroll to the bottom, ensure that you check the box Always use this app to open .kml files and then click Look for another app on this PC:

Then find the Google Earth application executable at C:\Program Files\Google\Google Earth Pro\client\googleearth.exe:

Terrain & 3D#

If your boundaries appear distorted or squiggly in Google Earth, that is because they are, by default, Clamped to ground and you have Terrain switched on (checked in the Layers panel, at the bottom-left in Google Earth). If you don't want a 3D view, simply uncheck Terrain and your boundaries should display normally.

If you do want a 3D view, you need to change the elevation of the boundary to be relative to ground. Right-click on PlanetGIS features in the Places panel, or on one of the features underneath it (if you want to make independent changes to separate features) and then click Properties. Then activate the Altitude tab and change from Clamped to ground to Relative to ground:

The boundaries will now appear as straight lines, but may still be invisible in places. You can try a 1m value in the Altitude input box to improve visibility.

Tile servers#

It is possible to create links to any tile server on the Internet, but the most common ones have already been added:

• Bing Aerials. This is the imagery used by Microsoft's Bing Maps (satellite layer). This is a good alternative to Google's because the images might be newer or of better quality, which might simply be the result of being taken at a different time of day or season of the year.
• Google Satellite. The same images that are available in Google Earth. The satellite naming is actually inaccurate, since at larger scales (higher zoom levels), they are actually aerial photographs.
• Google Maps. Street map images used by Google Maps.
• Google Hybrid. Images used by Google Maps with satellite layer activated.
• OpenStreetMap. Already introduced above.
• NGI Orthophotos. The NGI (SA government) images, hosted on a server provided by a volunteer of the OpenStreetMap project. This server currently (as of August 2024) contains recent images but may not be regularly updated in the future. The server may not be able to handle a lot of traffic, so the loading of the images can be slow.

Working with multiple maps#

As you have already seen, most of the maps use layers from other (secondary) maps. For example, each provincial cadastral map links to the SA administrative map for municipal and provincial boundaries. Once such a link has been set up, the maps remain interlinked and when one map that refers to layers in another map is opened, Planet will attempt to automatically open the secondary map.

In order to create a link to a map that hasn't been linked to already, you need to open both maps. In this case, you want your cadastral map(s) open as well as a contour map. We will use the 5m contour map in this example, but be aware that the whole country isn't covered by 5m contours. For some areas you may have to fall back to the 20m contour map.

If you are working with multiple provinces, or using the combined map for the included coutry-wide streetmap, you should be adding the contours to the combining map. Alternatively, you can do this on a provincial map, e.g. NW-cadastral.db. Once you have this map opened, use File → Open to open the contour map. (If you don't have one already, download it from your account page.) This map should be placed in the same folder as your cadastral map, or perhaps one level up so that you have (e.g.,) \Cadastral2024 and \Contours5m as sub-folders of your main mapping folder. Keeping the maps together like this (as opposed to on separate drives) makes it easier to copy them to another computer. This is because PlanetGIS stores a relative path to a secondary map, if possible.

Now that you have a contour map open, in addition to your cadastral map, use the Window menu to get back to your cadastral (or combining) map.

Adding a display#

The next step is to add the reference to a layer in a secondary map, to a view of your primary map. This reference is called a Display in PlanetGIS, and acts very similarly to a layer. You will see a tab on the right called Displays or if there isn't enough space for the text, an eye icon ():

1. Click the Displays tab to open the Display manager
2. Click on Click to add... or right-click on the whitespace below the other displays, then click Add...
3. Expand the SA-contours_5m project
4. Select Contours
5. Click the Select button or press Enter

Once you have added a new feature class into a view, PlanetGIS will zoom to the extent of that feature class. To get back to where you were on the map, you can click the Previous button () on the left.

Multiple selections#

Exporting Shape files#

Exporting CAD files (DXF)#