Map of the month
Urban land cover / land use change across Gauteng is beautifully portrayed in this month’s map of the month. The land cover/use layers are based on an interpretation of Landsat TM and ETM+ satellite imagery from 1991 and 2009, undertaken as part of Brian Mubiwa’s PhD research at the University of Johannesburg. Urban growth and suburban sprawl are clearly evident with the percentage of urban (built-up) land cover in Gauteng increasing from 12.6% in 1991 to 18.4% in 2009. Most of the development can be attributed to the massive RDP housing projects and growth of informal settlements on the outskirts of the cities. Johannesburg is the most urbanised municipality with 58% of its total municipal area built up in 2009, followed by Ekurhuleni and Tshwane with 44% and 39% respectively.
For a complete historical review of the evolution of urban spatial development from the 1890s through to the late 1980s, and more detailed statistics and maps describing the 1991 to 2009 growth, please refer to the GCRO Occasional paper: Historical spatial change in the Gauteng City-Region.
Population data from the Census 2011 (StatsSA) was mapped by race at ward boundary level across the GCR, where 1 dot on the map represents 100 people. Four areas are zoomed in, with a degree of racial integration evident in Johannesburg’s northern suburbs.
Area cartograms depict non-absolute space where the extent of a feature area is proportional to a measured value. In this map, the ESRI ArcGIS Cartogram Geoprocessing Tool (version 2), available from http://arcscripts.esri.com/details.asp?dbid=15638, was used to map Stats SA Census 2011 population data. The maps depict the total population per province in South Africa and per municipality in Gauteng. The actual areas of the provincial and municipal features are either under or over represented based on the total population but have retained a partially accurate relative location. The maps therefore depict interesting proportional and relative spatial differences in population data and do not reflect the geographic area of the administration boundary.
The South Africa cartogram depicts a striking relationship that exists between the area and population of the Northern Cape and Gauteng provinces, which have the largest and smallest administrative area per province, and the smallest and largest recorded population per province respectively. Gauteng can therefore be considered the beating heart of South Africa, as although it is the smallest province by administrative area, it supports the largest provincial population of 12 272 263. The Gauteng municipal area cartogram depicts the three metropolitan municipalities with the highest population in Johannesburg 4 434 830, almost a third of Gauteng's total population. The Johannesburg and Ekurhuleni metropolitan municipalities resemble the ventricles of a human heart – whose primary function is to act as the engine room of the body – just as the two metropolitan municipalities have been referred to as being the commercial and industrial engine rooms of South Africa.
Gauteng’s green infrastructure network is a living network of green spaces that contributes to the long-term sustainability and resilience of the Gauteng City-Region. The network provides various services, buffers the effects of climate change and improves the quality of life of the places in which we live. This map shows the hydrological, natural, agricultural and inter-connecting green networks that constitute the broader green infrastructure network in Gauteng. There is a great need to begin to understand and unravel the services that these green networks provide and identify what is required to manage and develop this living network in the future. This map was created by merging green layers from various sources collated by the GCRO as part of the Green assets and infrastructure project. An overview of the layers used in each of these categories is presented in the map legend.
Gauteng’s grey infrastructure is easily identifiable in built up urban areas where it commonly performs a single function in the landscape (e.g. storm water infrastructure that attenuates heavy rainfall events and floods). Grey infrastructure requires large investments and continuous management to ensure it provides quality services for the Gauteng community. Green infrastructure, on the other hand, is a multi-functional network that provides more sustainable alternatives to grey engineering and provides similar services to some of the current grey infrastructure in Gauteng. This map demonstrates Gauteng’s rich and diverse green infrastructure network which has the potential to provide alternative green services in the future. It was created using GTI 2.5m (2010) land cover data derived from GeoTerraImage (GTI). The source data was reclassified into its urban and green components and represented in two different data frames: a grey infrastructure frame depicting the urban componanents, and in contrast, a green infrastructure frame with the green components displayed.
The various settlement typologies across Gauteng are reflected in this land cover map (2.5m) derived by GeoTerraImage (GTI) from 2010 aerial/satellite imagery. The Sandton area, with a concentration of residential cluster settlements, is contrasted with the adjacent Alexandra showing a high level of informal housing. The Pretoria CBD area is depicted with a regular grid of streets and buildings, whereas densification with backyard shacks is clearly evident to the east of Pretoria in Mamelodi. Finally, the historical layout of Soweto is compared to more recent RDP settlement layouts in the Orange Farm area.
To highlight October transport month 2012, movement into and within Gauteng’s metropolitan municipalities, as measured in the GCRO’s 2011 Quality of Life survey, are depicted in this map. Each survey respondent’s main trip (such as to go to work, look for work, travel to a place of study, shop, take the children to school, etc.) is mapped as a ‘desire line’ from place of residence to the destination suburb. Note: only movement within Gauteng was captured in the QoL survey and movement into Gauteng from the neighbouring provinces, for example, the daily commutes in areas north east of Gauteng from Thembisile in Mpumulanga to Pretoria, are not reflected but form an important part of the city-regional transport picture.
It is clear that the City of Johannesburg is a central transport hub for Gauteng, with a significant transport corridor visible along the Johannesburg-Ekurhuleni (Edenvale/Modderfontein) boundary. In Tshwane, the central Pretoria area is a major destination with significant travel from the north western areas of Winterveld-Mabopane. The three maps highlight the major inter-municipal movement between the metros and the need for an integrated transport plan for Gauteng.
The emergence of privately governed space in Gauteng has increased since the early 1990s and has fragmented the urban form through the transformation of space from open to controlled access. This month’s map depicts the development of privately governed space in Gauteng, which includes gated communities, office parks, boomed-off areas and estates. This form of development has created a series of fragmented cells scattered across the Gauteng landscape, but located mainly in the Johannesburg, Tshwane and Ekurhuleni Metropolitan municipalities. This cellular structure limits the accessibility, movement and integration of individuals in these areas. The cells are also observed to coincide with areas of low building density.
This map was created using Eskom spot building count (2010) and AfriGIS gated communities (2012) data. The Eskom spot building count (2010) data was used to create a point density heat map in order to illustrate the density of buildings within a 500m2 radius. The emergence of privately governed public space, represented by the series of scattered hollow cells across Gauteng, was represented by overlaying the AfriGIS gated communities (2012) data onto the point density heat map.
The second map of a series of 2011 GCRO Quality of Life (QoL) survey maps, highlights the 26% of survey respondents that migrated to Gauteng from other provinces. The QoL survey asked all respondents who had migrated into Gauteng to identify the place that they came from, or the nearest large town, based on a list of place names provided to them. Nearly a third of all internal migrants came from Limpopo (29%), followed by 19% from KwaZulu-Natal and 13% from Mpumulanga.
This map is the first of a series of 2011 GCRO Quality of Life (QoL) survey maps. The province of Gauteng attracts people from all over South Africa and other countries. Almost four out of ten respondents in the survey (38%) had migrated to Gauteng. The origin of the 6% of survey respondents that migrated into Gauteng from another country are highlighted in July’s QoL map.
New economic activity in the central urban spine of Gauteng is reflected in this month’s map of the month. The growth in new industrial and commercial buildings was derived from the GeoTerraImage growth indicator dataset, which contains a point per building, with its associated land use. The buildings with an industrial or commercial land use that were present in the 2009 but not in the 2001 database, were extracted and mapped as a dot density “heat” map to reflect the density of new industrial and commercial growth from 2001 to 2009. Please note: this map was generated using two different versions of 2001 and 2009 data (which used slighly different capture methodologies) and only provides an estimation of industrial and commercial growth.
The May map of the month depicts population density in Gauteng per 1 km2 square grid. Data was derived from the Lightstone 2010 DemProKey X dataset which has a 2010 population estimate of 11,1 million for Gauteng. The enumerator level population data was proportionally split and assigned to a randomly generated 1 sq km grid. The highest density of 64 823 people per km2 occurs in the Johannesburg CBD area, followed by Alexandra (42 300).
This GCRO map depicts the results of the Gauteng Department of Agriculture and Rural Development (GDARD) Agricultural Census of 2009. GDARD commissioned the census for Gauteng in 2008 and it was completed in October 2009. The census provides field-level, georeferenced data of high-value crops and livestock in the Province, wherever access to fields and farms was possible. Specific crop types, cultivation regimes and cultivation of winter and summer crops were defined per field for many parts of the province.
The GCRO map of the month presents some of the agricultural activities that were recorded through the survey. It shows the significant land-use allocated to the cultivation of crops, vegetables, fruit, flowers and herbs, as well as livestock farming, despite the region being viewed as a predominantly urban hub. Some agricultural space-economy choices are clearly visible from the map. For example the location of flower and herb farming close to the centre of the province reflects the time-sensitive nature of production of these crops, where easy access to transport infrastructure and export facilities affects the financial viability of these businesses.
Polygons indicated in blue show cultivation in agricultural tunnels, with the outlines of the polygons indicating the relevant type of agriculture in these areas.
The urban extent of Gauteng is reflected in this map that depicts urban land cover derived from 2009 satellite imagery supplied by GeoTerraImage (GTI). The urban land cover class is defined by GTI as: “All built-up areas, including all aspects of residential, commercial, industrial, mining and transportation infrastructure, in both urban and rural environments. Represents primarily a non-vegetated, artificially sealed surface, except for vegetated gardens not otherwise identified as urban-trees or urban-grasslands. Also includes all major road and rail networks, recently cleared, non-vegetated areas being prepared for urban development, and rural farm infrastructure (including greenhouses, propagation tunnels and chicken / pig batteries).”
Urban land cover constitutes 15% of the total land coverage in Gauteng.
Through a systematic data collection effort over several months in late 2011 and early 2012, GCRO has collected all the available digital spatial data on flood-plains and flood hotspots in Gauteng. This is significant in that this data has historically been collected separately by municipalities, and never before been collated and combined to give an integrated Gauteng overview. This map of the month presents the regional topography of the Gauteng City-Region, with the hydrology of Gauteng highlighted. The hydrological features include wetlands, perennial and non-perennial rivers and wetlands, with the delineated flood-plains and flood hotspots in the province shown in orange. Unfortunately there is no flood-plain data for the previous Metsweding area, or Sedibeng, and the only data for the West Rand are key flood risk sites and areas shown as orange dots.
A comparison of the 2006 and latest 2011 municipal boundaries within Gauteng. The amalgamation of Metsweding District Council (consisting of Nokeng tsa Taemane and Kungwini local municipalities) with City of Tshwane is clearly visible – Tshwane now covers a massive 35% of the province, with a population of 2 597 428, according to Lightstone DemprokeyX 2010 population estimates. City of Johannesburg has the largest population in Gauteng, 3 785 074, followed by Ekurhuleni with a population of 2 932 431. Another major boundary change was the incorporation of the West Rand District Management Area (Cradle of Humankind world heritage site) into Mogale City.
This point (dot) density map depict the numbers of adults that are receiving social grants (according to 2010 estimates as per the Lightstone (Pty) Ltd’s DemproKeyX database), spatially presented as one dot representing 100 persons receiving grants, per ward. This is overlaid with a spatial layer depicting dolomitic ground within the Gauteng Provincial boundary. The map depicts the large numbers of poor people that live on potentially dangerous ground – often in low income and informal settlements across the province.
Economic activity across Gauteng using the AfriGIS/Matrix Marketing’s BizCount 2010 database of companies to generate a hotspot analysis of the total number of firms per square kilometre, using a 2km radius scale. The map illustrates clearly that businesses concentrate in the centre of the province, clustering into a number of key nodes. It is also clear that there is much less economy in the south, far north, and outlying parts of the city-region.
Population data from the Census 2001 (StatsSA) was mapped by race at ward boundary level (2009 ward boundaries) across the GCR using dot density symbology where 1 dot on the map represents 100 people.
Map showing the district/metropolitan boundaries and local municiapalities constituting Gauteng in 2009. The neighbouring district and local municipalities are also highlighted. Adminstrative boundary layers obtained from the Municipal Demarcation Board. Inset map indicates the relative position of the GCR within Southern Africa.
Population density across the GCR is mapped using the Census 2001 small area layer (SAL) from StatsSA using dot density symbology, where 1 dot represents 100 people. A 100km and 175 km radius is also displayed to indicate the Census 2001 population of approximately 10 million and 13 million, within 100km and 175 kms of the Joburg CBD respectively.
Map depicting the Gauteng province and Local/Metro Municipalities with topographical relief layer as a backdrop.
Map depicting the Gauteng province and Local/Metro Municipalities with satellite imagery backdrop.
Map used by Fieldworkers for the Quality of Life survey 2009. The city and town place names were used for the respondents to identify where they work, shop and look for work. Each Local/Metropolitan Municipal area within Gauteng assigned a number, with areas neighbouring Gauteng grouped into regions.