Daniele La Rosa [email protected]From land use to land cover: evapotranspiration assessment in a metropolitan region Università di Catania Dipartimento di Architettura e Urbanistica LAboratorio per la Progettazione del Territorio e dell’Ambiente www.lapta.dau.unict.it Sesta Conferenza Nazionale in Informatica e Pianificazione Urbana e Territoriale – INPUT 2010 Buildings Cultivated Im pervious Shrubs Trees Herbaceous vegetation Bare soils Grass Fig.2 Land covertypesiden Potenza 13 - 15 Settembre 2010
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From land use to land cover: evapotraspiration assessment in a metropolitan region, di Paolo La Greca, Daniele La Rosa, Francesco Martinico, Riccardo Privitera
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B = BuildingsG = GrassT = TreesI = ImperviousBS = Bare soil
C = CultivatedHV = Herbaceous vegetationS = Shrubs
Example of land cover types extraction
Land cover analysis for Non Urbanised Areas (2)
The study area (1)
Catania Metropolitan Area
27 MunicipalitiesArea: ~ 950 Km2
Pop: 581413
The study area (2)
Metropolitan area population dynamics (1961 – 2008)•Grows more than 27%•Main city (Catania) looses 16%, other 26 municipalities increase of 107%•In 2008, about 60% of total population live outside the main city
Built up areas AREA [sqm] %
% cumulated
Before 1936 3353327 6,2% 6,2% From 1936 to 1964 2867105 5,3% 11,5% From 1964 to 1985 37249790 69,0% 80,5% From 1985 to 2000 10550606 19,5% 100,0%
Total 54020828 100,0%
~ 1600% growth in 80 years
Metropolitan area urban growth (1936 – 2008) *
Catania Metropolitan Area
* Catania not included
The study area (3)
Mascalucia Municipality
•Population almost doubled twice since 1936 (27482 inhabitants)•Three land use master plans from 1960s•Agriculture oriented economy, mainly based on wine production, completely swiped out, first, by holiday houses developments in the 1960 -1970s. In the following 20 years these houses became stable dwellings.
One of the small agricultural towns on the volcano slopes absorbed into the expanding metropolis
Expanding metropolis
The study area (4)
Land Use
Residential Areas Farmlands
Abandoned Farmlands Woods and Shrubs
Sources:•vector cartography (1:10,000) regional authorities•municipal vector cartography (1:2000)•recent high resolution ortophotos (2007-2008)•Field surveys (for most recent changes)
The study area (5)
Mascalucia Municipality•Residential land covers almost half of the municipality•Farmland (cultivated and abandoned) more than 21% •wood and shrubs (20,5 %). •Roads surfaces also sum up almost 10 % of the total.•Relevant amount of small patches of farmland, eroded by urban sprawl. •Farmland, shrubs and wooden patches, represent the Non Urbanized Areas scattered within the municipality.
Land Use
Land use type Area [ha] %
Abandoned farmland 215,1 13,2%
Farmland 135,7 8,3%
Woods and shrubs 333,4 20,5%
Parks and public gardens 24,5 1,5%
Trading 8,7 0,5%
Manufacturing 1,8 0,1%
Services and utilities 38,0 2,3%
Residential 704,4 43,2%
Private gardens 13,5 0,8%
Parkings 3,4 0,2%
Roads 150,9 9,3%
Total 1629,5 100%
LAND COVER
The study area (6)
Mascalucia Municipality
•Urban land increased by more than 2000 % between 1928 and 2008 (from 35,7ha to 718,4 ha)
Built up area Area Area Ha %
1928 357481 35,7 4,74%
1964 476947 47,7 6,32%
1985 4543156 454,3 60,24%
2000 1737788 173,3 23,04%
2008 425903 42,1 5,65%
TOT 7115372 753100,00%
Urban growth
From Land Use to Land Cover
Land use categories not able to provide indications about land cover features.
Each patch of a single land use type composed by a (complex) mix of land covers
Characterizing land uses type by different land covers becomes crucial for environmental planning (i.e. climate change adaptation strategies)Different percentages of evapotranspiring surfaces can be taken into account in deciding prospective land uses or safeguard measures.
Why a Land Cover assessment of NUA?
Land Cover Analysis (1)
Buildings
Cultivated
Impervious
Shrubs
Trees
Herbaceous vegetation
Bare soils
Grass
Fig. 2 Land cover types iden
Land Cover Analysis (2)
Land Cover Types
A geographic sampling strategy
1.Overlay of 30 meters square grid over each land use type
Need of a geographic sampling to assess land cover (mapping small land cover features is a time consuming task)
Detached houses Woods and shrubs
Land Cover Analysis (3)
A geographic sampling strategy 2. Random choose of cells for each grid•Each land use type sampled with different size
samples with Cochran Formulas (Cochran, 1977)•Confidence level and interval fixed at 85% and 5%
Land Cover Analysis (4)
•Sample cells randomly generated with the Random Selection ArcMap tool
0%10%20%30%40%50%60%70%80%90%
0 1000 2000 3000 4000 5000 6000 7000 8000
Land use Types # of cell Sampled cells %
Abandoned farmland 2230 107 4,8%
Farmland 1549 105 6,8%
Woods and shrubs 3576 109 3,0%
Parks and public gardens 279 80 28,7%
Retail 93 51 54,8%
Manufacturing 20 17 85,0%
Services and utilities 415 89 21,3%
Detached houses 6804 110 1,6%
Historical compact settlement 363 86 23,7%
Multi-storey apartment residences 714 97 13,6%
Linear historical rural settlements 85 49 57,6%
A geographic sampling strategy
3. Aerial photo interpretation of the land cover types
Inside every sampled cell, land cover surfaces manually digitalized by photo interpretation
ResultsComposition of land cover surfaces for each land use type*
* Residential land use type further divided in: historical compact urban settlements, multi-storey apartment residences, linear historical rural settlements and detached family houses.
•Residential land use types show some of the highest proportion of trees cover surface.•Shrubs are higher in Abandoned Farmland (36%) than in Woods and Shrubs (33%). Woods and Shrubs land use type are more characterized by shrubs vegetation than by trees.
Trees Shrubs Cultivated GrassHerbaceous vegetation Bare soil Buildings Impervious TOT