Information and Knowledge Management using ArcGIS ModelBuilder

Teresa Santos, Ségio Freire and José António Tenedório
Remote sensing imagery due to its spectral, temporal and geographic characteristics, can be used in
monitoring processes, as a source for related information like land use and land cover, surface
roughness, terrain relief or soil moisture. Sawaya et al. (2003) explored the potential of VHR IKONOS
and QuickBird satellite imagery for mapping and analysis of urban impervious surface area and water
resources at local scales. Bauer et al. (2004) mapped and quantified the degree of impervious surface
area over a large geographic area and over time, using a multi-temporal Landsat imagery data set.
Yuan and Bauer (2006) compared the normalized difference vegetation index (NDVI) and percent
impervious surface as indicators of surface urban heat island effects in Landsat imagery. Aponte
(2007) used a QuickBird image in order to detect different types of impervious surfaces, and studied
the relationship between the rainfall-infiltration-runoff rates, the land cover and the geomorphologic
susceptibility. Zhang et al. (2009) extracted vegetation and impervious surface as indicators of urban
land surface temperature from IKONOS imagery.
The present work details the development of an updated and detailed map of imperviousness for the
city of Lisbon using IKONOS-2 satellite imagery. The Vegetation-Impervious-Soil (VIS) model,
developed by Ridd (1995), was used as the basis for extracting land cover information at the cityscale.
It is a conceptual representation that allows simplifying the analysis of urban surfaces by
decomposing it in three basic land cover components: vegetation, impervious surface and soil.
After collecting data on land cover from remote sensing data, several indicators can be assessed.
Indicators on land sealing area, quantification of green area, or the vacant land available in the city,
are ecological measures that can be used for monitoring and analyzing trends over the territory.
Studies on impacts of urbanization, responses to natural and man-made disasters, vulnerability
analysis or housing conditions, all require land-based indicators. The geographical data constitute the
base of the spatial representation of the indicators. Urban indicators are designed to measure the
quality of life and the nature of development of an urban area. These indicators can be used to make
policy and planning decisions, to identify whether policy goals and targets are being met, and
sometimes to predict change.
2. Data set and study area
The dataset explored in this paper includes spectral data, acquired by the IKONOS-2 satellite. The
IKONOS image was acquired in June, 30, 2008, and has a spatial resolution of 4 m in the
multispectral mode (visible and near-infrared bands) and 1 m in the panchromatic mode, and a
radiometric resolution of 11 bits.
The study area is the city of Lisbon (Figure 1). The municipality occupies an area of 84 Km 2 , and is a
typical European capital city, with a very diverse land use dynamics, varying from historical
neighborhoods where the street-network is dense and the most of the area is built-up, to modern
residential ones, with on-going construction of roads and multi-family buildings. Between these two
situations, there are more heterogeneous places with land uses such as residential, parks,
agriculture, vacant land, industrial, utilities, and schools.
3. Methodology
The cartographic workflow based on remote sensing data, begins with the pre-processing stage
where the images are orthorectified. Afterwards, the digital processing takes place to produce a map
with the location of the land cover features.
The nomenclature is organized in two levels of detail, following the VIS model. The 1 st level includes
the classes “Vegetation”, “Impervious Surfaces”, and “Soil”. On the 2 nd level, seven classes were
defined: “Trees”, “Low Vegetation”, “Buildings”, “Roads”, “Other impervious surfaces”, “Soil”, and
“Shadows and Water” (Table 1).
Green areas are an important land use in urban areas which perform relevant environment functions,
such as improving urban climate, reducing atmospheric pollution, providing amenities, aesthetical
benefits and a good environment for urban population. Green land cover includes trees, shrubland,
herbaceous and agriculture fields.
Impervious surfaces can generally be defined as anthropogenic features, such as roads, buildings,
sidewalks and parking lots, through which water cannot infiltrate into the soil. The artificial surface
cover can be used to evaluate the quality of urban streams, and to study effects of runoff. Impervious
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