Block indicators
The table block_indicators contains the block identifier (id_block), the identifier of the RSU it belongs to (id_rsu) and a certain number of indicators described below.
Description: Area of the block footprint.
Method: Sum(building area)
Description: Mean building’s roof height within a block (the building height being weighted by the building areas).
Method: SUM(Bu_Wall_Height * Bu_Area) / SUM(Bu_Area)
Description: Indicates how equal is the block building direction distribution (having nb_direction directions of analysis).
Method: From the building direction distribution created in the MAIN_BUILDING_DIRECTION indicator calculation, an indicator of equality of the distribution is calculated:
→ Sum(Min(1/nb_direction, length_dir_i/length_all_dir))
Range of values: [nb_direction, 1] - the higher the value the most equal is the distribution
Description: Indicates how unique is the RSU main building direction.
Method: From the building direction distribution created in the MAIN_BUILDING_DIRECTION indicator calculation, an indicator of uniqueness of the main direction is calculated:
→ | Length_First_Dir - Length_Second_Dir | / (Length_Second_Dir + Length_First_Dir)
Range of values: [0, 1] - the closer the value from 1, the more unique is the main building direction
Description: This calculation indicates if a block has a large closed courtyard. This information could be useful for the urban fabric classification proposed in Thornay et al. (2017) and also described in Bocher et al. (2018). It answers to the Step 11 of the manual decision tree which consists in checking whether the block is closed (continuous buildings the aligned along road).
Method: In order to identify the RSU with closed blocks, the difference between the st_holes(bloc scale) and SUM(st_holes(building scale)) indicators is calculated.
Warning: this method will not be able to identify blocks that are nearly closed (e.g. 99 % of the RSU perimeter) while it would be interesting to know how much the block is closed (for ventilation purpose for example).
References:
- Bocher, E., Petit, G., Bernard, J., & Palominos, S. (2018). A geoprocessing framework to compute urban indicators: The MApUCE tools chain. Urban climate, 24, 153-174.
- Tornay, Nathalie, Robert Schoetter, Marion Bonhomme, Serge Faraut, and Valéry Masson. "GENIUS: A methodology to define a detailed description of buildings for urban climate and building energy consumption simulations." Urban Climate 20 (2017): 75-93.
Description: Total floor area within the block.
Method: Sum(building floor area)
Description: Density of hole within a block.
Method: Block courtyard area / block area
Description: Main orientation of the buildings within the blocks (from the North, clockwise).
Method: The smallest rectangle enclosing each building is calculated. Then each side of the rectangles are attributed to a direction range (by default every 15° within the [0, 180°[ interval - from North, clockwise). For each direction range, the length of the sides of all rectangles contained in a block are summed. Finally, the mode of this distribution is set as the main building direction within the block.
Description: Net block’s compactness, defined as the ratio between the area of its free external facade and its building volume.
Method:
→ SUM((Bu_Contiguity * Bu_Perimeter + Bu_Hole_Perimeter) * Bu_Wall_Height)/Sum(Bu_Volume)
Description: Variability of the building’s roof height within a block (the building heights being weighted by the building areas).
Method: By default, the indicator of variability is the Standard Deviation (STD) defined as :
→ SUM(Bu_Area*(Bu_Wall_Height - AVG_HEIGHT_ROOF_AREA_WEIGHTED)^2)) / SUM (Bu_Area)
Description: Volume of buildings composing a block.
Method: Sum(building volume)
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