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Geographical analysis and Geographical analysis and numerical - - PowerPoint PPT Presentation

Jan 05, 2024 937 likes •1.27k views

Geographical analysis and Geographical analysis and numerical quantification numerical quantification of visual impact for aerogenerators of visual impact for aerogenerators and photovoltaic panels and photovoltaic panels using Open Source

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Geographical analysis and Geographical analysis and numerical quantification numerical quantification

  • f visual impact for aerogenerators
  • f visual impact for aerogenerators

and photovoltaic panels and photovoltaic panels using Open Source GIS using Open Source GIS

  • A. Minelli,
  • A. Minelli, I. Marchesini,
  • I. Marchesini, P. De Rosa, L. Casagrande & M. Cenci
  • P. De Rosa, L. Casagrande & M. Cenci

Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Sun and wind farm: the visual impact Sun and wind farm: the visual impact

It seems the heaviest to most of the people

Is it possible to quantify it?

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To quantitatively define the visual impact we developed a GRASS GIS GRASS GIS module: module:

Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

r.wind.sun r.wind.sun

Visibility quantification Visibility quantification

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Aerogenerators: Input Aerogenerators: Input

Vector layer of aerogenerators position Heigth of the aerogenerators Computational distance DEM

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Photovoltaic panels: input Photovoltaic panels: input

Vertical dimension of the single panel Maximum computational distance Panel height above the ground Horizontal dimension of the single panel Inclination of panel Azimuth of the panel Minimum computational distance Vector layer of panels position (centroid) DEM

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

I = impact index (relative size of the object) Aobj = distorted object size AFOV = observers' Field Of View The impact index The impact index

I = Aobj AFOV

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

We define the static FOV as an ellipsoidal, three-axes, shape The dimensions of the FOV axes depends on:

  • the distance “d” ( from the observer) at which FOV is calculated
  • three angles:
  • Nose

se = = 85°

  • Superio

ior = = 6 65°

  • In

Infe ferior = r = 7 70° i=d*tg(70°) s=d*tg(65°) n=d*tg(85°)

Static Field Of View Static Field Of View

d

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

First approach: from his point of view the observer can rotate his view all around 360°

Dynamic Field Of View Dynamic Field Of View

Height: h= (s+i) Circumference: l=2πd

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

The dynamic FOV is the internal area of a cylinder: I*h.

Dynamic Field Of View Dynamic Field Of View

h= (s+i) l=2πd This approach is adopted to calculate the FOV for the assessment of the visual impact due to the photovoltaic panels

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Second approach: from his point of view the observer can both rotate his view all around 360° and look up and down The dynamic FOV area is the area of a sphere: A=4πd 2.

Dynamic Field Of View Dynamic Field Of View

Since both horizontal and vertical dimension of the aerogenerators are not negligible, this approach is adopted to estimate FOV for the assessment of the aerogenerators visual impact

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Perceived shape and size Perceived shape and size

Fixing a proje jecti tive p pla lane Π, the relative size and shape (red line) depends on:

  • the distance (d) between the object and the observer;
  • the mutual observer – object height (∆h).

d

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Perceived shape and size Perceived shape and size

In general, the projecti tive p pla lane Π can also be placed at a distance r != d. In that case the field of view is also estimated at the distance “r”. In that way the ratio between field of view and the object size is maintained constant d r

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

An aerogenerator has a quite complex shape. In order to simplify the analysis, the area covered by the rotor is considered completely filled.

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Two components are considered separately: tower and rotor The size becomes the sum of the areas of a trapezius (tower) and an ellipse In fact the rotor vertical axis is quite ever deformed from the point of view of the

  • bserver

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

tower rotor

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

If the aerogenerator is fully visible: the center of view (red point) is placed between the rotor and the tower

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

The length of vertic ical a axis is of th the e ell llip ipse and the heig igth th o

  • f t

f the tr trapezium are calculated

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Since the aerogenerator rotor can turn (to be ever perpendicular to the main wind direction), the width of the rotor ellipse is, conservatively, not altered

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

If the terrain hides a large part of the tower: the tower is not considered for the analysis

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

If the terrain covers up also part of the rotor:

  • nly half of the rotor area is considered

Aerogenerators: perceived shape and size Aerogenerators: perceived shape and size

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Considering a single aerogenerator, it is possible (using a DEM) to evaluate the Impact Index map. For each point (raster cell) of the surrounding area:

Single Aerogenerator: Impact index Single Aerogenerator: Impact index

I = Aobj AFOV

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

The Impact Index apply also in case of multiple aerogenerators

Multiple aerogenerators: Impact Index Multiple aerogenerators: Impact Index

I =∑ Aobj AFOV

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Photovoltaic panels: perceived shape and size Photovoltaic panels: perceived shape and size

The problem of relative shape and size change also apply to the Photovoltaic Panels. The size an shape change both vertically …...... and horizontally

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Photovoltaic panels: perceived shape and size Photovoltaic panels: perceived shape and size

Fortunately the distorted shape of a rectangle is a parallelogram or a trapezium, so it is easy to calculate its the area.

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

The Impact Index must be calculated for each panel or group of panels.

Photovoltaic panels: Impact Index Photovoltaic panels: Impact Index

I =∑ Aobj AFOV

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

r.wind.sun: results r.wind.sun: results

The r.wind.sun output is a raster layers of the sum of the impact index calculated for each photovoltaic panel or aerogenerator

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

r.wind.sun: results r.wind.sun: results

Generally speaking the value of each cell represents the

  • ccupancy, of the field of view, determined by the presence of all

the aerogenerators or photovoltaic panels

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

The raster layers can be reclassified to be easily interpreted.

r.wind.sun: results r.wind.sun: results

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

The 3D visualization allows to highlight the effect of the partial hiddenness, due to the terrain, of the aerogenerators

r.wind.sun: results r.wind.sun: results

2 3 4 3 2 2 3 4 5 6 1 Aerogenerators

1=low impact … … 6=high impact The Impact Index values decrease towards the aerogenerators

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

Moreover, by means of the GRASS GIS nviz tool, the r.wind.sun module allows for a 3D view of the aerogenerators

r.wind.sun: results r.wind.sun: results

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

  • The module r.wind.sun is a preliminary answer to the question

concerning the possibility to estimate the visual impact of aerogenerators and photovoltaic panels

  • We acknowledge that the relative dimension is only a part of the

visual impact assessment

  • We put in evidence that this method can be used for other kinds of

landscape offending structures

  • We emphasize that, using a common field of view approach, the

results obtained for different kind of structures, that exist on the same territory, can be combined.

r.wind.sun: conclusions r.wind.sun: conclusions

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Gfosservices Gfosservices Studio Associato Studio Associato Regione Regione Umbria Umbria

r.wind.sun: download r.wind.sun: download

r.wind.sun is written in Python and will be soon available at the GRASS GIS addons web page: http://grass.osgeo.org/wiki/GRASS_AddOns

Thanks for the attention! Thanks for the attention!