Daniele La Rosasdlarosa@tin.it

From land use to land cover: evapotranspiration assessment in a

metropolitan region

Università di CataniaDipartimento di Architettura e

UrbanisticaLAboratorio per la Progettazione del

Territorio e dell’Ambiente

www.lapta.dau.unict.itSesta Conferenza Nazionale in Informatica e Pianificazione Urbana e Territoriale – INPUT 2010

Buildings

Cultivated

Impervious

Shrubs

Trees

Herbaceous vegetation

Bare soils

Grass

Fig. 2 Land cover types iden

Potenza 13 - 15 Settembre 2010

Summary• Non Urbanised Areas (NUA) for urban planning

(climate changes minimisation strategies)• Study area

– Catania Metropolitan area– Municipality of Mascalucia

• Land cover analysis of NUA (method and results)

• Uses of Land Cover for land use suitability model

Non Urbanised Areas for climate changes minimisation strategies

Role of Non Urbanised Areas as fundamental issue to achieving high levels of urban quality together with adaptation to climate changes

Climate changes as new challenge to urban and regional planning

Loss of evapotranspiring surfaces and vegetated soils is one of the main consequences of urban sprawl processes.

Land cover analysis for Non Urbanised Areas (1)

Land cover analysis for evapotranspiration

How much evapotranspiring and permeable are the different land use types?

Each patch of land uses characterized by different land cover types

buildingsimpervious grasscultivatedtreesshrubs herbaceous vegetationbare soil

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

B=buildings I=impervious G=grass C=cultivated T=trees S=shrubs HV=herbaceous vegetation BS=bare soil

Land Cover Analysis (5)

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

Detached houses 25% 6% 7% 25% 0% 4% 13% 20% 100%Historical compact settlements 15% 0% 0% 18% 0% 1% 38% 29% 100%Multi-storey apartment residences 15% 0% 0% 13% 0% 0% 39% 34% 100%

Linear historical rural settlements 32% 0% 0% 18% 0% 0% 38% 13% 100%

Private gardens 30% 11% 6% 24% 8% 2% 10% 9% 100%

Retail 4% 0% 0% 9% 0% 14% 24% 49% 100%

Manufacturing 2% 0% 0% 6% 0% 10% 20% 61% 100%

Services and utilities 8% 7% 3% 12% 6% 14% 16% 34% 100%

Farmland 6% 15% 50% 2% 9% 10% 1% 5% 100%

Abandoned Farmland 12% 36% 11% 0% 18% 19% 1% 2% 100%

Parks and public gardens 85% 0% 0% 5% 2% 0% 1% 7% 100%

Woods and shrubs 13% 33% 5% 2% 20% 19% 2% 7% 100%

LA

ND

US

E T

YP

ES

LAND COVER TYPES

Land Cover Analysis (6)

Results

Diversifying land use types by the percentage of their evapotranspiring and impervious surfaces

LAND USE TYPES

% evapotranspir

ing surface

% impervious surface

Detached houses 62,1% 33,7%

Historical urban areas 32,3% 67,1%

Multi-storey apartment residences 27,6% 72,4%

Linear historical rural settlements 49,4% 50,6%

Private gardens 79,0% 19,0%

Trading 12,2% 73,4%

Manufacturing 8,3% 81,5%

Services and utilities 35,9% 50,5%

Farmland 83,1% 6,6%

Abandoned farmland 77,8% 2,9%

Urban greenspaces 92,2% 7,7%

Woods and shrubs 72,1% 8,7%

•evapotranspiring land cover types = Trees, Shrubs, Cultivated, Grass, Herbaceous Vegetation

•impervious land cover types = Buildings and Impervious

Land Cover Analysis (7)

ResultsExtraction of Non Urbanised Areas and their classification into 4 classes (equal interval)

Land Cover Analysis (8)

Leisure

Suitability Land Use Suitability Model of NUA

Which land use strategies for the broken grid of NUA?Which strategies for climate change adaptation?

Environmental protection

New forms of agricultures

Uses of Land Cover Analysis (1)

Uses of Land Cover Analysis (2)

ENVIROMENTAL PROTECTION

LEISURE LOCAL GREEN SERVICES

URBAN AGRICULTURE

Land Use Suitability Strategy Model

What we are currently working on

Some important issues emerged with the work progress

Land cover types provide the same contribution to evapotranspiration/ permeability

Weighting each land cover type with a coefficient considering the different potential of evapotranspiration and permeability.

Different results by Manual or Automatic Approaches?

Testing on same study area Feature Analyst for land cover extraction

Thank you

From land use to land cover: evapotranspiration assessment in a

metropolitan region

Daniele La Rosasdlarosa@tin.it

Università di CataniaDipartimento di Architettura e

UrbanisticaLAboratorio per la Progettazione del

Territorio e dell’Ambiente

www.lapta.dau.unict.itSesta Conferenza Nazionale in Informatica e Pianificazione Urbana e Territoriale – INPUT 2010

Potenza 13 - 15 Settembre 2010