How to Use the Cadastral Maps
Provincial Maps
Each of the nine provinces' cadastral data has been loaded into a separate PlanetGIS project. If you only work in a single
province, you can use that province's cadastral map by itself. In the example below, we have extracted the NW
folder
from the downloaded NW-cadastral.zip
and placed it in a folder named D:\PlanetGIS 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
.
Street Map
Every time we update the cadastral maps from the Surveyor General's data, we also update the SA OpenStreetMap
from the OpenStreetMap.org project. This is a worldwide map with
information contributed by volunteers and organisations donating their data. The map is ideal for use in a GIS because it
has regular identifiable vector features, but most people actually use OpenStreetMap's tile server
which provides
images of the map over the Internet.
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.
Combined Map
The SA-cadastral-streetmap.db
project combines the administrative boundary map, all nine provinces' cadastral
maps and OSM:
This is a PlanetGIS project with no features, but it references the 11 projects to create the above view
. To get
this map as well as the 11 secondary maps, you can download SA streetmap & all provinces' cadastral combined
zip
(or much smaller .7z) from the Subscription data section. This is what the contents of
the downloaded SA-Cadastral-OSM-2024.zip
looks like in File Explorer:
The zip/7z contains a single folder, (currently) Cadastral2024
. You can extract (e.g., drag and drop) this folder
to an appropriate location on your hard drive. Inside the folder, you will see 9 sub-folders for each province's cadastral
map, and 4 PlanetGIS projects:
SA-administrative.db
contains boundaries and links to various tile servers;SA-cadastral.db
combines the 9 provinces' cadastral maps into one, along with an OSM tile background, plus other tile server options;SA-cadastral-streetmap.db
adds the OSM vector data to all the cadastral maps; andSA-openstreetmap.db
contains all the OSM vector data for SA.
(SA-cadastral-streetmap.db
opens all 13 projects, while the other projects open only some of them.)
Locating a property
The cadastral maps have a specially developed land parcel locator
, designed specifically for use with the cadastral
map databases. To access this tool, click on the Locate
button ()
or use the Locate
menu:
PlanetGIS has a generic Locate entities
function and adds any custom plug-in
locator tools below it.
If you click on the Locate
button and get the generic Locate entities
window, you either do not have a
cadastral map opened or the plug-in was not loaded because it was not found in the same location as the cadastral map's database.
If you opened a province's cadastral map by itself, you will see two menu items under the Locate
button:
Locate entities
and Locate a land parcel
. With the combined maps, you will see locators for all
9 provinces as can be seen in Figure 12.
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 andholding
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 asparent
) 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 StateC
: Cape TownN
: KwaZulu-Natal
T
andN
are always followed by a0
and then the 2-letter registration divisionC
andF
are followed by a 3-digit administrative region code
0000added to the major region
Viewing boundaries in Google Earth
With one or more land parcel boundaries selected in PlanetGIS, you can click View → In Google Earth → Selected features
:
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.
Using web tiles (background images)
We have already introduced web tiles
earlier in this chapter, along with a list
of pros and cons. The first thing that you might want to do is to switch these off in your maps, because they can make it
hard to see features, especially photographic backgrounds combined with the text of your labelled features (e.g., erf numbers).
You can control the visibility of web tile layers, just like any other layer, in the Displays
tab. Simply
click on an eye to show or hide a display.
NB: You can only display one layer of web tiles at a time. PlanetGIS will ignore all but the bottom-most visible
web tiles display. In this example (Figure 23), if you want to show Bing Aerials
, you would also need to hide
OpenStreetMap
.
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.
Adding a contour map
PlanetGIS Explorer allows you to change the maps to suit your purposes. Keep in mind that when you update the maps to a new version, your changes will be lost. There are ways around this, described elsewhere in the documentation pages, but making minor changes to the maps directly is much easier than to create new PlanetGIS projects. Here we will shortly describe the process of combining layers from different maps, specifically, adding contours to a cadastral map.
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 ():
- Click the
Displays
tab to open the Display manager - Click on
Click to add...
or right-click on the whitespace below the other displays, then clickAdd...
- Expand the SA-contours_5m project
- Select
Contours
- 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.