Remote sensing and Spatial Metrics in monitoring Urban Sprawl

Urbanisation has become a universal truth found everywhere in the world. According to the United Nations the trend of inhabitant‟s growth in inner-cities is expected to heighten to 72% by 2050. Urbanisation, though an important international spectacle, has become a daunting challenge worldwide because dependable and precise data essential for growth of urban plans are not often readily available for planning. In the absence of such planning, quick development causes chaotic and unexpected growth of urban centres with a growing populace that results in congestion and turns into a problem of inadequate social infrastructure. It is through a collective effort of having material on historical and current land use, that scheduling and monitoring of the sprawl can become effective through the use of auxiliary plans for monitoring spatial (X, Y) positions and land use trends in its completest to produce an amalgamation of improved land use, the creation of real infrastructures to deal with the region‟s surroundings and pastoral areas, and the advancing synopsis for forecasting urban procedures for land use forms and land use modifications. Urban growth has an important impact on the rural peripheral territories located around the major urban centres which themselves soon become uncontrolled urbanised. To evaluate the geographical situation and the consequences of urbanisation in rural space, the urban sprawl of Ga Municipal Assembly (GA) which had evolved from Ga rural districts is monitored by remote sensing over a thirty-year period. The urban burden on these rural spaces is characterised by different land cover/land use conversions and land use conflicts. This study scrutinises the active change forms in the expansion course of the GA Municipalities over a period of 30 years and consequently attempts to categorise the urban growth forms and describe the probable driving forces causative to these variations in the GA municipalities by means of remotely sensed data and population count data. Spatial and time-based dynamics information of expansion progression was computed using Landsat imagery and socio-economic data, supervised classification procedure using the maximum likelihood technique in ENVI 5.0 software and the post-classification change detection method. The results indicate that the total population had increased from 157,985 persons in 1986 population projection census to 1,039,687 persons in 2016 census projection as a result of migration, displacement and natural population growth. The main land use in the study area currently is Settlements which had increased from 7.10% (55.395Km²) iniii 1986 to 62.09% (482.9175Km²) in 2016. Dense Vegetation had decreased from 69.65% (539.1459Km²) coverage in 1986 to just 7.44% (57.834Km²) in 2016 due to transference to other uses. The foremost driver of Urbanisation was due to immigration. The study investigated the status of Ga area, by identifying, characterizing and quantifying the urban growth using remote sensing techniques coupled with statistical data calculation. This approach was effective in detecting LULC modification and measuring the range of the urban expansion. Moreover, it was discovered that, the Urbanization progression was powerfully associated with augmented inhabitants. It is recommended that, to protect Agricultural lands and proper Land use planning for an advancing economy, there should be: i. A Strict Land Use planning policy developed and adhered to for any developmental project conducted in the District which must take into consideration Environmental Impact Assessment (EIA). ii. The planning should include designated belt areas for agricultural lands and forests to prevent conversions as well as protection zones for water bodies. iii. There should be decentralized development driven from the district for social amenities and infrastructures to preserve cultural identity instead of immigration driven that also imports city values to replace cultural values.

Source: KNUST