Research and Development in Roof-Top Solar Potentiality Using LiDAR Technology

Mr. Radhey Shyam Meena M.Tech Scholar (Power System)

Student Member - The Institute of Engineering & Technology (IET), UACEE

Mr. Jeetendra S Rathore Mr. Mukesh Lodha Mr. Manish Agarwal Ms. Shivani Johari M.Tech Scholar Asst. Prof. EED Asst. Prof. EED Head & Asst. Prof. EED

Dept. Of Electrical Engineering

Sri Balaji College Of Engineering & Technology Jaipur Rajasthan Technical University Kota

Abstract: Energy security and its application is the key for economic growth to any country and state. The conventional generation is also the source of greenhou se gas emission attributing to global warming and has has adverse impact on climate. Therefore, a global shift towards sustainable renewable energy generation is being witnessed. India is blessed with abundant solar energy and if harnessed efficiently, Solar energy is extremely beneficial as it is non polluting and its generation can be decentralized. The state of Rajasthan receives maximum solar radiation Intensity in India with very low average rainfall. It also has desert land available in abundance. The refore, Rajasthan is likely to emerge as the global hub for solar power in the country. Challenge of climate change and global warming

properties tha t could not be achieved before. LiDAR is extremely useful in atmospheric and environmental research as well as space exploration. It also have wide application in industry, defense, and military. LiDAR mapping is an accepted method of generating precise an d directly referenced spatial information about the shape and surface characteristics of the earth. Recent advancement in mapping systems and their enabling technologies allow scientists and professionals to examine natural and built environments across a wide range of scales with greater accuracy, precision, and flexibility then ever before. There are many considerations and trade offs that must be understood in order to make sound decisions about the procurement, processing, and application of LiDAR data. This paper Challenge of climate change and global warming

continuously threaten the world community, and Rajasthan govt. Has also recognized the urgent need to tackle these challenges. In this paper a methodology is provided for the application of Light Detection and Ranging (LiDAR) to automated solar photovoltaic (PV) deployment analysis on the regional scale. Challenges in urban information extraction and management for solar PV deployment assessment are determined and quantitative solutions are offered. This paper highlights a need for connectivity between demographic information, electrical engineering schemes and geographical information systems (GIS) and a typical factor of so lar PV suitable roof area that can be extracted per method. conclusions are developed to provide guidelines for a final methodology with the most useful information in situations of incomprehensive GIS data to facilitate the processing of LiDAR, low budget s for both time and finance, and personnel with diverse expert in computer vision. The methodology can

processing, and application of LiDAR data. This paper provide introductory and review information for application of LiDAR Technology in solar PV system. It has become an established method in todays technology for information collecting and elevation data across landscapes different project sites including for solar system , wind , and other new renewable energy sources. This is sensing technique as similar to radar but in radar we use radio wave and here we use laser light pulses. It collected ground based stationary and mobile collect points in site areas. Three dimensional representation also possible for new system of rail road and building development structures. LiDAR, which is commonly spelled and also known as LADAR or laser altimetry, is an acronym for light detection and ranging. It refer s to a remote sensing technology that emits intense, focused beams of light and measures the time it takes for the reflections to be detected by the sensor. This information is used to compute ranges, or distances, to objects. In this with diverse expert in computer vision. The methodology can

be adapted for use anywhere that LiDAR and urban GIS data is available. Key Words : Light Detection and Ranging (LiDAR), Renewable Energy Source , Photovoltaic, Computing Sensing, New Generation Technology.

I. Introduction A. LiDAR LiDAR stand for Light Detection and Ranging, commonly known as Laser Radar. It is not only replacing conventional sensors, but also creating new methods with unique

used to compute ranges, or distances, to objects. In this manner, LiDAR is anal ogous to RaDAR (Radio Detecting And Ranging), except that it is based on discrete pulses of laser light. The three - dimensional coordinates (e.g., x,y,z or latitude, longitude, and elevation) of the target objects are computed from The time difference betw een the laser pulse being

emitted and returned, The absolute location of the sensor on or above the

surface of the Earth.

F i gu r e 1. S c h e m ati c d i ag r am o f A i r b o r n e L i D A R p e r fo r m i n g l i n e s c an n i n g r e s u l ti n g i n p a r al l e l l i n e s o f m e as u r e d p o i n ts(o th e r s c an p a tte r n s e x i s t , b u t th i s o n e i s fa i r l y c o m m o n)

T h e r e a r e t w o c l a s s e s of r e m o t e s e n s i n g t e c hn o l o gi e s t hat

a r e di f f e r e n t i a t e d b y t h e s o ur c e of e n e r gy us e d t o de t e c t a

t a r ge t :

P a s s i v e S y s t e m s

A c t i v e S y s t e m s .

P a s s i v e s y s t e m s de t e c t r a d i a t i o n t h a t i s ge n e ra t e d by a n

e xt e rn a l s o u r c e o f e n e r gy , s uc h a s t h e s u n, w hi l e a c t i ve

S o l a r P h o t o vo l t a i c (P V ) e n e rgy c o n ve r s i o n o f f e r s as us t a i na b l e m e t h o d o f pr o duc i n g e l e c t r i c i t y t o prov i de forS o c i e t y n e e ds . T h e a dv a n t a ge o f P V i n ge n e ra t i on ofe l e c t r i c i t y a re-

L o n g t e rm e c o n o m i c g r o w t h i m p r o v e m e n t f o r a n yc o un t r y t h a t a gg r e s s i v e l y de ve l o ps t h e t e c hn o l o g y .P r o v i de a a s s i s t a n c e i n e n e r gy s e c uri t y.N o a t m o s ph e r i c e m i s s i o n s o r ra d i o a c t i v e w a s tege n e ra t i o n du ri n g us e.

It a c t s a s a di s t ri b ut e d e l e c t ri c a l ge n e ra t i o n s o ur c e a nd h e n cer e d uc e s t h e de pe n de n c e a n d p r e s s ur e o n t h e c e n t ra l ut i l i t y

e xt e rn a l s o u r c e o f e n e r gy , s uc h a s t h e s u n, w hi l e a c t i ve

s y s t e m s ge n e r a t e a n d d i r e c t e n e r gy t o w a rd a t a r ge t a n d

s ub s e que n t l y de t e c t t h e ra di a t i o n. L i D A R s y s t e m s a re

a c t i v e s y s t e m s be c a us e t h e y e m i t p ul s e s o f l i ght ( i . e . t h e

l a s er b e a m s ) a n d de t e c t t h e r e f l e c t ed l i g ht . T h is

c h a ra c t e ri s t i c a l l o w s l i d a r d a t a t o b e c o l l e c t e d a t n i g ht

w h e n t h e a i r i s us u a l l y c l e a r e r a n d t h e s ky c o n t a i n s l e s s a ir

t r a f f i c t h a n i n t h e da y t i m e . I n f a c t , m o s t l i da r da t a a re

c o l l e c t e d a t ni g ht . U n l i ke r a da r, l i d a r c a nn o t pe n e t r a te

c l o uds , r a i n , o r de n s e h a z e a n d m us t b e f l ow n du ri n g f a ir

w e a t h e r. L i D A R i n s t r u m e nt s c an r a p i dl y m e a s u r e t h e

E a rt h s u r f a c e , a t s a m p l i n g ra t e s g r e a t e r t h a n 150 k i l o h e rtz

(i . e . , 15 0, 00 0 pu l s e s pe r s e c o n d). T h e r e s ul t i n g p ro duc t i s a

de n s e l y s pa c e d n e t w o r k o f h i g h l y a c c ur a t e ge o re f e r e n c e d

e l e v a t i o n po i nts o f t e n c a l l e d a po i n t c l o ud t h a t c a n be

r e d uc e s t h e de pe n de n c e a n d p r e s s ur e o n t h e c e n t ra l ut i l i t yl i n e s i n s y s t e m s wi t h h i g h po t e nt i a l f o r b l a c ko ut s a n dov e r l o a ds . T hi s ha s l e d t o i n t e rna t i o n a l c o o p e r a t i o n a n dt e c hn o l o g y i n v e s t m e nt o v e r t h e pa s t 2 5 y e a r s , w h i c h i n t u rnha s g i v e n ri s e t o f a n t a s t i c ga i n s i n s o l a r P V c e l l pe r f o r m a n cea n d a p re di c t e d c h a ngi n g l a n ds c a pe i n R & D a c t i v i t i e s f o rs o l a r c e l l t e c hn o l o gi e s . S o l a r c e l l s m a de f r o m a v a r i e t y ofm a t e ri a l s ha v e de m o n s t ra t e d e f f i c i e n c i e s ov e r t e n pe r c e nt a n da r e c urr e nt l y m a n uf a c t u r e d gl o b a l l y . As t h e t e c hn o l o gi c alpr o f i c i e n c y of t h e s o l a r c e l l i n d us t r y m a t u r e d , t h e t o t als h i pm e n t s o f s o l a r c e l l s i n c r e a s e d r a pi d l y . In t h e l a s t de c adegl o b a l s o l a r P V de pl o y m e n t h a s i n c r e a s e d f r o m 1 G W t o 16G W w i t h an a nnua l g r o w t h ra t e o f m o r e t ha n 40% , T h isgr o w th r a t e , w h i l e i m p r e s s i v e , m us t b e ke pt i n c o n t e xt o f t hegl o b a l e n e rgy m a r ke t . T h e i n c r e a s i n g t e c hn o l o gi c a lc o m pe t i t i v e n e s s o f s o l a r P V , a m o n g o t h e r ki nds o f r e n e w a b lee n e rg i e s , ha s c o n t ri b ut e d t o -

A n e w l o gi c o f i n f ra s t r uc t u r e P r o v i s i o n a l .A pa ra d i gm s h i f t i n e n e rgy po l i c y.e l e v a t i o n po i nts o f t e n c a l l e d a po i n t c l o ud t h a t c a n be

us e d t o ge n e ra t e t hr e e - di m e n s i o n a l r e p r e s e nt a t i o n s o f t he

E a rt h s u r f a c e a n d i t s f e a t ur e s . M a n y L i D A R s y s t e ms

o pe r a t e i n t h e n e a r - i n f ra r e d r e gi o n o f t h e e l e c t r o m a g n e t ic

s pe c t r um , a l t h o ug h s o m e s e n s o r s a l s o o pe ra t e i n t h e g r e e n

b a n d t o pe n e t ra t e w a t e r a n d de t e c t b o t t o m f e a t u r e s . T h e se

b a t h y m e t ri c l i dar s y s t e m s c a n b e us e d i n a r e a s w i t h

r e l a t i v e l y c l e a r w a t e r t o m e a s u r e s e a f l o o r e l e v a t i o n s .

B. P h o tov o l tai c S ys te m

A pa ra d i gm s h i f t i n e n e rgy po l i c y.H ow e ve r , i n t h e de b a t e s o n u r b a n a n d r e gi o na l de v e l o pm e nta n d r e gi o na l i n f r a s t r uc t u r e po l i c y , t h e i n t e g ra t i o n o f di f f e r e n tdi s c i pl i n e s (G e o gra p h i c I n f o rm a t i on S y s t e m (G IS ),e n v i r o n m e n t a l m o de l i n g , u r b a n p l a nni n g , e l e c t r i c a l a n dm e c h a ni c a l e n gi n e e ri n g) a nd t h e i r r o l e s i n t h e de l i v e r y ofut i l i t y s e r v i c e s s t i l l s e e m s t o b e t a ke n f o r g r a nt e d by t hepub l i c a nd w i t hi n e a c h s i n gl e di s c i p l i n e a n d t o b e l e f t t oe n gi n e e r s , n e t w o r k o pe ra t o r s a nd na t i o n a l u t i l i t y r e gul a t o r s .Co n s e que n t l y , t h e r e ha s b e e n l i t t l e r e s e a rc h o n t h e u r b a n a n dr e gi o n a l i m p a c t s o f ut i l i t y r e s t r uc t u ri n g a nd t h e c h a n g i n ge n v i r o n m e n t f o r u rb a n a nd r e g i o n a l go ve rn a n c e w i t h a

large -scale introduction of PV. To take advantage of PV anding of

the urban local potential (roof space and solar exposure among others) is critical for utility planning, accommodating grid capacity, deploying financing schemes and formulating future adaptive policies . The paper describes a methodology that is part of the complex process of assessing solar PV potential for a region using the Renewable Energy Region (RER). Specifically the methodology provides an application of Light Detection and Ranging (LiDAR) of urban to automated solar PV deployments on a municipal unit, which can be scaled up first to the level of a city and then the cities within the RER region. The primary stakeholders for this research are local and

002

2 )()()( TALTRR

ARRTR

tRP

fovrbg

r

a

t

r

Here

Pr(R)=Optical power received from range R in J/s

t= Transmitted pulse energy in J

Ta = Atmospheric one way path transmittance time in s

w = Angular scattering coefficient in m-1 sr1

Ar/R2 = Projected solid angle of r eceiver as seen from

scatterer at range R in sr

= Overlap function

L A = Incident back ground power in W The primary stakeholders for this research are local and regional utilities companies,municipal government and academic research on regional ener gy modeling. Challenges in urban information extraction and management for solar PV deployment assessment are determined and quantified. This study provides the following contributions: A methodology that integrated the cross - disciplinary

competences in r emote sensing (RS), GIS, computer vision and urban environmental studies.

A robust methodology that can work with low - resolution, spatially and temporally inconsistent and incomprehensive data and reconstruct vegetation and buildings separately and concur rently.

Recommendations for future generations of software.

II. Main Equations Concept

LbgArfov = Incident back ground power in W The LiDAR equation for analog detection or photon

counting

bg

r

a

t

rNTR

R

ARRTR

hRN

02

2 )()()(

Here Nr(R) = Number of photons received from range R

t= Transmitted pulse energy in J

Ta

= Atmospheric one way path transmittance time in s

w = Angular scattering coefficient in m-1 sr1

Ar/R2 = Projected solid angle of receiver as seen from

scatterer at range R in sr

= Overlap function

Range calculated from light travel time

dtRn

cdR

)(

Minimum range resolution, is the range uncertainty, which

= Nbg = Received background photons in ph

III. Technical Platforms

Airborne topographic LiDAR systems are the most

common LiDAR systems used for generating digital

elevation models for large areas. The combination of an

airborne platform and a scanning LiDAR sensor is an

effective and efficient technique for collecting elevation

data across tens t o thousands of square miles. For smaller

areas, or where higher density is needed, LiDAR sensors

can also be deployed on helicopters and ground - based (or

water - based) stationary and mobile platforms. LiDAR was

first developed as a fixed - position ground - based instrument

for studies of atmospheric composition, structure, clouds, Minimum range resolution, is the range uncertainty, which results from the smaller of the laser pulse width or the A/D sample rate:

n

tclengthpulseR

22

t = Optical pulse width or interval, n = Reference index of medium The LiDAR equation that is used for solution of optical

power received from range R is given blow -

for studies of atmospheric composition, structure, clouds,

and aerosols and remains a powerful tool for climate

observations around the world. Modern navigation and

positioning systems enable the use of water - based and

land -based mobile platf orms to collect data.

IV. Installation Story A. LiDAR & PV In order to determine PV potential for a city the ideal circumstance is having access to a 3D urban model , which requires that individual buildings are represented, next to urban vegetation, st reets, and other objects of the city

i n f ra s t r uc t u re s uc h a s w a t e rc our s e s , po w e r s uppl y l in e s , a ndin di vi du a l o b je c t s l i ke st r e e t s ig n s o r f oun ta in s. A D i gi t alSur f a c e M ode l (D SM ) de r i v e d f ro m po i n t c lo uds a cqui re d byL i DAR o r s te re o- ph o t og r amm et r y w i l l i nd i r e c t l y r e p r e s e ntb uil di n gs . W h i le s uc h m o de l s c a n b e ge n e r a t e d e as i l y a ndeven a ut om a ti c a l l y, t h e y on l y r e pre se nt t h e a ppr o xim a t e r oofs h ape s w i t h o ut ge n e ra l iz a t i on a n d w it h o ut d i st i n gui shi ngb e tw ee n in di v i dua l b uil di n gs o n t h e o n e ha n d a nd b e t w e enb uil di n gs a n d o t h e r o b je c t s l i ke g ro un d a nd v ege t a t i o n on t heo t h er ha n d. If b uil di ng or b ui l di n g b l o c k o ut li n e s (e . g . , f romca das t ra l ma ps ) a r e pr o vi de d, m ode ls ext rac t ed f r o m t hecomb i n e d L i DA R an d G IS da t a a re e nha n c ed and su r f acem ode l s c a n b e ge n e rat e d f o r i ndiv i dua l bui l di ngs o r bl o c ks.How eve r , th e s e m o de l s s t i l l do n ot a l lo w a d i s t in c ti on

B. S ys t e m D e t e c t i onR e l i a b l e a n d a c c u r a t e b ui l d i n g ge n e ra t i o n f ro m L i D A R da tar e qui r e s a n u m b e r o f pr o c e s s e s be y o n d c a pt u r e o f a c c ur a tera w da t a . T h e s e a r e b ui l di ng de t e c t i o n , o b j e c t s e gm e nt a t i o n ,b ui l di n g e xt ra c t i o n , r o o f s h a pe r e c o n s t r uc t i o n a nd m o de l i n gqua l i t y a n a l y s i s . T h e m a j o r i t y of a v a i l a b l e l i t e r a t u r e:

Co n c e n t ra t e s o n i ndi v i du a l a s pe c t s o nl y a n d h e n cede t a c h e s t h e r e a de r f r o m t h e b i g p i c t u r e;O nl y us e s (a s s o c i a t e d) da t a o f c e r t a i n (e xc e l l e nt ) qua l i t yo r c us t o m i z e d c l a s s i f i e r s t ha t a r e o n l y pr o f e s s i o n a l l ykn o w n o r n o t pub l i c l y a v a i l a b l e (e Co gn i t i o n , F e a t u reA na l y s t ); a n dH a s l i m i t e d a ppl i c a t i o n s i n t e r m s o f t h e de gr e e ofH ow e ve r , t h e s e m o de l s s t i l l do n o t a l l o w a d i s t i n c t i o n

b e t w e e n i n d i v i dual r o of f a c e s , n o r b e t w e e n r o of a n d do rm e rso r o t h e r o bj e c t s , w h i c h i s i m po rt a nt i n t h e c o n t e xt o f s o l a r PVi n s t a l l a t i o n s b e c a us e a w h o l e r o o f P V i n s t a l l a t i o n i s n o ta l w a y s f e a s i b l e . F urt h e r m o r e , a rt i f a c t s o f da t a a c qui s i t i o n ,e . g. , c a us e d by o c c l uded a r e a s , s a m pl i ng d i s t a n c e , orr e m a i ni n g ge o - r e f e r e n c i n g e rr o r s , a r e t y pi c a l l y fo un d i n s uchm o de l s . V e r t i c a l w a l l s m a y a ppe a r s l a nt e d o r n o t a ppe a r a t a l lduet o t h e 2 . 5D g ri d r e p r e s e nt a t i o n. A f t e r t h e c l e a n - up o f s uc he rr o r s , r o of s i z e s w i l l ge n e r a l l y be s m a l l e r t h a n t h e i r a c t u als i z e s , t h e r e by r e duc i n g t h e ir s h a do w i n g po t e n t i a l . I n t hee xt r e m e c a s e s , s hado w e f fe c t s of a dj a c e n t b ui l di n gs m a y n o tb e c a pt ur ed.T o i n c r e a s e t h e r e l i a b i l i t y of t h e b ui l d i n g m o de l s a s w e l l ast h e r a n ge o f po s s i b l e appl i c a t i o n s , a dd i t i o n a l k n o w l e dge o nb ui l di n gs ha s t o b e i n c o r po ra t e d i nt o t h e m o de l i n g p r o c e s s .T y pi c a l a s s um p t i o n s a r e t o de f i n e w a l l s a s b e i n g v e r t i c a l a n dr o o fs a s b e i n g a c o m po s i t e of pl a n a r f a c e s . T hi s l e a ds t o an

H a s l i m i t e d a ppl i c a t i o n s i n t e r m s o f t h e de gr e e ofc o m pl e xi t y t h a t t h e p r o duc t a l l o w s .

A l t h o ug h u r b a n t e xt u r e m o de l i n g i s hi g h l y d y n a m i c (due t ot h e na t u r e o f t h e m o de l e d o bj e c t ) a n d c o m pl i c a t e d (due t o t her e qui r e d p r e c i s i o n a nd i n t e r di s c i p l i na r y i n t h e n um b e r ofi n v o l ved e xpe r t i s e and t h e i nh e re n t i nt e ra c t i o n b e t w e enh u m a n s a nd t h e u r b a n e n v i r o n m e n t ). T h e m e t h o do l o g y forb ui l di n g de t e c t i o n s ub s e que n t l y de r i v e d a n d de s c ri b e d h e rew a s de s i gn e d t o c o m pr o m i s e b e t w e e n c o s t s a v i n gs a n d t hes m o o t h e s t a n d m o s t e f f e c t i v e l y e s t a b l i s h e d l e a rni n g c ur v epo s s i b l e fo r a n a ud i e n c e a s s u m e d t o h a v e n o p r e v i o us t ra i ni n gi n c o m put e r p r o g r a m m i n g , r e m o t e s e n s i n g o r d i gi t a l i m agepr o c e s s i n g. A n u n de r s t a ndi n g o f t h e c o m pl e xi t y of G IS da tai n t e g r a t i o n in e n e rgy m o de l i n g m e a n s an i m p ro v edi n t e r - di s c i p l i na r y a pp r e c i a t i o n f o r t h e v a l ue o f a s t r e a m l i n e da n d c o m pre h e n s i v e da t a s y s t e m . F u r t h e r , t h e a b i l i t y t o c a rr yo ut pa rt o f t h e p r o c e dure w i l l h e l p f a c i l i t a t e t h e pe n e t r a t i o n o fs o l a r P V i n t o t h e c u rr e n t e l e c t ri c i t y gr i d . I n t h e a b s e n c e ofr o o fs a s b e i n g a c o m po s i t e of pl a n a r f a c e s . T hi s l e a ds t o an

i de a l i z a t i o n o f t h e b ui l d i n gs . T h e t ra n s i t i o n z o n e o f t won e i g h b o r i ng r o o f f a c e s , f o r e xa m pl e , b e c o m e s a s t r a i g h t l i nede f i n e d by t h e i n t e r s e c t i o n o f t w o r o of pl a n e s . T hei m po rt a n c e o f t h e s e c o n s i de r a t i o n s i s r a i s e d w h e n i t c o m e s t oP V s y s t e m de s i g n a n d pe r ro o f i n s t a l l a t i o n : t hi s e nha n c edm o de l i s s uf f i c i e n t i nput f o r r a p i d r o of a s s e s s m e n t . H e n c e am o de l i ng m e t h o d i s n e e de d f o r P V a pp l i c a t i o n s t ha t i s:

A c c ura t e, i . e., i t s h o uld p r o duc e s i m pl e po l y go n alm o de l s f i t t i n g t h e i n pu t po i n t c l o uds i n a p r e c i s e m a nn e r.Ro b us t : r e g a r dl e s s o f t h e d i v e r s i t y a n d c o m pl e xi t y o fb ui l di n g r o o f s h a pe s t h e m e t h o d s h o ul d a l w a y s g e n e ra teb ui l di n g m o de l s c o m p r i s e d o f f l a t p l a n e s t ha t a r e asc o n t i n uo us l y a n d s m o o t h l y c o nn e c t e d a nd t r a n s i t i o n eda s po s s i b l e e ve n w i t h t h e e xi s t e n c e o f un de s i r ede l e m e n t s s uc h a s r e s i dua l n o i s e a nd s m a l l r o of f e a t ur e s .Co m pl e m e nt a r y t o t h e 2 . 5D c ha ra c t e ri s t i c : t h e m e t h o ds h o ul d c r e a t e 2 . 5D po l y g o n a l m o de l s c o m po s e d ofde t a i l e d r o of s a nd v e r t i c a l w a l l s c o nn e c t i ng r o o f l a y e r s .

s o l a r P V i n t o t h e c u rr e n t e l e c t ri c i t y gr i d . I n t h e a b s e n c e ofc a da s t ra l da t a , t h e r e a r e s e v e r a l e f f e c t i v e m e t h o ds f orb ui l di n g de t e c t i o n t ha t w o r k we l l o n l a rge r b ui l d i n gs a l t h o ughs m a l l e r b ui l d i n gs a r e o f t e n m i s s e d . B ui l d i n g de t e c t i o n c a n b ec a rri e d o ut s o l e l y o n t h e L i D A R da t a o r i n h y b r i d w i t h o t h erda t a s uc h a s a e r i a l p h o t o s a n d e xi s t i n g b ui l di ng o ut l i n e s .B ui l di n g o ut l i n e s a r e t h e i nt e r s e c t i o n o f t h e b ui l d i n gs w i t h i tss urr o u n di ngs , i n ge n e ra l t h e t e rra i n . T h e o ut l i n e s t ha t a r e us edfo r t h e a p p ro a c h us e d h e re h a v e t w o a dv a nt a ge s : f i r s t l y , t h e yr e p r e s e n t t h e r e a l s hape a nd s i z e o f t h e r o o f , a n d n o t t hedi m e n s i o n o f t h e b a s e m e n t . A nd s e c o n dl y , a ppl y i n g t h e s a meda t a a s us e d f o r t h e e v a l ua t i o n e n s u r e s t h e c o m pa ra b i l i t y oft h e r e s ul t s d u r i n g t h e p r o c e s s of t h e e v a l u a t i o n . T h e yc o n c l ude d t ha t l a s e r s c a nni n g i s m o r e s ui t a b l e t h a n t r a di t i o na lph o t o gra m m e t r y fo r de ri v i n g b ui l d i n g h e i g ht s , e xt r a c t i n gpl a na r ro o f f a c e s a n d r i dge s o f t h e r o of s . H ow e v e r,ph o t o gra m m e t r y a n d a e r i a l i m a ge s l e a d t o b e t t e r re s ul t s inb ui l di n g o ut l i n e a n d l e n g t h de t e rm i na t i o n.

de t a i l e d r o of s a nd v e r t i c a l w a l l s c o nn e c t i ng r o o f l a y e r s .

V . M e th o d o l o gy

A s o ut l i n e d a b ov e , a w i de r a n ge o f t e c h ni que s h a v e b e e n us ed

t o e xt ra c t b ui l di n g ge o m e t r y , a n d i n p a r t i c ul a r r o o f ge o m e t r y ,

f r om L i DAR po i n t c l o uds a n d f ro m i ma ge r y w i t h or w i th outin depe n de n t b ui l din g o ut l in e da t a . O ur f o c us i s o n ra pid,

m ode l s t o as s e s s p ho t ovo l t a i c s o l ar po t ent i al ofne i g h b o rho o ds . U n l i ke m o s t o f th e m e t h o ds de s c r i b e d ab ov e,exa c t n e s s i s n ot de em ed a s e s se n t i a l a s i s ge n e ra l i t y t o a w idev ar i e t y o f s i t uat i o n s a n d e f f i c i e n c y i n s pi t e o f r e a l i s t i c a l lym i xe d d a ta qua l i t y . T h e m e th o do l o g y us e d h e re i s b a s e d onth e f o l low i n g f i v e a ss um pt i on s: ( i ) in div i du a l bui l d i n g r oofar ea s c an b e m o de l e d p r ope r l y by a co m po s it i o n o f pl an erf a c es ; (i i) a n y t h i n g b e l ow a ch o s e n e l e v a t io n c ut o f f isirr e l e v an t f o r s o la r PV po t e nt i a l as s e s s m en t ; ( i i i ) t reeca no pi e s a re o paque ; (i v) sm a ll w i ndo w s o n t h e r oo f s,ov e rha ngs o n th e w a ll s , H e a t i n g , V e nt a n d A i r Condi t io ni ng

f r e e fo r P V pa n e l s ; (v ) t h e h e i ght o f t h e o bje c t ands ub s eque n t l y th e a l t i m e t r y of th e D i gi t a l Su r f ac e M o del(D SM ) i s t h e d i f fe re n c e b e tw e en L i DARs z v a l ue s a n d ana v ai l ab l e D EM a nd (v i ) t h e r e i s n o dis c r e pa n c y i n t h e f o rm ofur b an s truc t u re s b e t w e en A e r i a l P h o t o s (A P) a n d L i DAR(i . e., t h e s e da t a s e t s w e r e c o l l e c t e d a t o r n e a r t o t h e s a m e t i m e ).A m o n g m ul t i pl e l e v e l s of r e t u rn s t ha t L i D A R of f e r s , t h e l a s tr e t u rn s o f t h i s a r e a w e r e us e d f o r r o o f c o n s t r uc t i o n s i n c e t h e yw e r e c o n s i de r e d t o m o s t l i ke l y r e a c h t h e c l o s e s t t o t h e g r o u n dh e n c e t h e l a s t o b j e c t o n t h e g r o un d o r t h e g ro u n d i t s e l f w o uldb e pi c ke d up by t h e l a s t pu l s e s . E s pe c i a l l y fo r b ui l d i n gs l a s ta n d f i r s t r e t u rns a r e t h e s a m e ( i n z v a l ue s ), w h i c h w asc h e c ke d w i t h t h e c u rr e n t d a t a s e t . A c o m pl e t e f l ow c h a r ts h o w i n g t h e s t e ps t ha t p r e c e de t h e c r e a t i o n o f a D S Mov e r ha n gs o n t h e w a l l s , H e a t i n g , V e nt a n d A i r Co n di t i o ni n g

f a c i l i t i e s (H V A Cs) a n d a n t e nnas do n o t o c c up y s o l a rge as pa c e t h a t i t s o m i s s i o n a dds s i g n i f i c a n t a r e a t o t h e r o o f a re a

s h o w i n g t h e s t e ps t ha t p r e c e de t h e c r e a t i o n o f a D S Mpr e s e nt e d i n t hi s pape r a n d a pp l i e d f o r t hi s s i m ul a t i o n i s gi v eni n F i gu re s . -

F i g. 1(a) . Th e c l as s i fi c ati o n o f p o i n ts b as e d o n th e o b je c ts t h ey c o r r e s p o n d to w as c a r r i e d o ut

F i g. 2 (b ) R o o f s e gr e gat i o n w as d o n e u s i n g MatL ab

(a ) (b)

F i g. 1( c ) C o n s tr u c ti o n an d I r r ad i an c e M o d e l i ng

P V R oo f F i tti ngT h e s ub po i n t s a t t hi s po i n t a r e r e a dy t o b e s e gm e n t e d a n dus e d f o r r e c o n s t r uc t i o n . I n a m a t h e m a t i c a l s e n s e , s i n c e t hea s s um pt i o n i s t h a t e a c h p l a n e c a n b e r e p r e s e nt e d b y a di s t i n ct

i n t e r po l a t i o n i n r e gi o n g r o w i n g . E q ua t i o n s f o r h o ri z o n t a l r o off a c e s a r e r e l a t i v e l y e a s y t o c o n s t ruc t , b ut t h o s e f o r s l a n t e df a c e s h a v e f i r s t t o b e re c o gn i z e d b y R A N S AC b e fo r e be i n gl i n e a rl y r e g r e s s e d by t h e S i n gu l a r v a l ue D e c o m po s i t i o na s s um pt i o n i s t h a t e a c h p l a n e c a n b e r e p r e s e nt e d b y a di s t i n ct

e qua t i o n i n t h e Ca rt e s i a n c oo r di na t e s , s e gm e nt a t i o n i s t ode r i v e s uch e qua t i o n s , w h i ch a re i n t u rn s us ed f or

l i n e a rl y r e g r e s s e d by t h e S i n gu l a r v a l ue D e c o m po s i t i o n( S V D ) a l go r i t hm.

F i g. 3 . A v e r ti c a l cu t o f an e x am p l e h o u s e n e x t to a tr e e s h o w i n g th e b u ffe r an d th e e l e v ati o n c u to f f. I n ad d i t i o n i t s h o wsF i g. 3 . A v e r ti c a l cu t o f an e x am p l e h o u s e n e x t to a tr e e s h o w i n g th e b u ffe r an d th e e l e v ati o n c u to f f. I n ad d i t i o n i t s h o ws

th e v e r t i c a l e x te n t o f th e fo u r r i n gs u s e d fo r c l as s i f i c ati o n.

V I . D i s c u s s i on an d F u t u r e W o rk

A s c a n b e s e e n t h e r e s ul t s a r e w i t h i n n u l l e rr o r g i v e n f i v e keya s s um pt i o n s : ( i ) i ndi v i du a l b ui l d i n gs c a n b e m o de l edpr o pe rl y by a c o m po s i t i o n o f pl a n e r f a c e s ; (i i ) a n y t h i ng b e l owa c h o s e n e l e v a t i o n c u t o f f i s i rr e l e v a nt f o r s o l a r P V po t e nt i ala s s e s s m e n t ; (i i i ) t r e e c a n o pi e s a r e o paque ; ( i v ) s m a l l w i n do wso n t h e r o of s , o ve r ha n gs o n t h e w a l l s ,

H V A Cs a n d a nt e nna s do n o t o c c up y s o l a rge a s pa c e t h a t t h e iro m i s s i o n a dds s i g n i f i c a n t a r e a t o t h e r o of a r e a f r e e f o r PVpa n e l s ; (v ) t h e h e i g ht o f t h e o b j e c t a n d s ub s e que n t l y t hea l t i m e t r y of t h e D S M i s t h e di f f e r e n c e b e t w e e n L i D A R s Zv a l ue s a nd t h e D E M ; a n d (v i ) n o di s c r e pa n c y i n r e a l t i meur b a n s t r uc t u r e s b e t w e e n a e ri a l p h o t o s (A P ) a n d L i D A R .N e i t h e r w i l l i t a f fe c t t h e v a l i d i t y of t h e D S M a s t h e e l e v a t i oni s p r e s e r v e d. T h e r o o f ar e a , h o w e v e r , w i l l b e s m a l l e r , s i n cet h e r o of a r e a w a s t w i c e r e duc e d: t h e f i r s t t i m e by t h e us e o f ab u f f e r a l o n g t h e e dge s a n d t h e s e c o n d t i m e by t h e po i n t

thinning effective in the RANSAC script. That means the output would be a conservative estimation of area available for PV panels. The methodology presented here is a continuation of previous attempts made urban rooftop data for determination of the regional PV potential on rooftops. However, this method is more inter disciplinarily transparent, comprehensive and has the advantage of relaxing the mandatory data quality. On its own it is the next piece of the pyramidal procedure to estimate solar photovoltaic potential from a regional level, to a municipal level and now a household scale. Given these qualities, it is suitable for use in regions without good LiDAR data and part of it is possible for utilities in the developing countries where these techniques are at an early stage of

VIII. References

[1] Smith, Michael E, 2007. Form and meaning in the earliest cities: a New approach to ancient urban planning. Journal of Planning History 6, 3 e 47

[2] Devereux, B.J., Amable, G.S., Crow, P., 2008. Visualization of LiD AR terrain models for archaeological feature detection. Antiquity 82, 470 e 479

[3] Moore, E., Freeman, T., Hensley, S., 2007. Spaceborne and airborne radar at Angkor: introducing New technology to the ancient site. In: Wiseman, J., El - Baz, F. (Eds.), Remote Sensing in Archaeology. Springer, New York, pp. 185 e 216.

[4] Olz, S.; Sims, R.; Kirchner, N. Contribution of countries where these techniques are at an early stage of development. The weakness of this methodology is a compromise between mat hematical sophistication and technical adaptability, between automation and intensive supervision.The aspects mentioned in this paper, mainly pertaining to the integration of spatial information in energy modeling, are among the bottlenecks to the process of integrating solar PV (and other forms of renewable energy) into the current electricity grid.

VII. Conclusions

The paper provides a methodology for the application of LiDAR to automated solar photovoltaic deployment analysis on the regional scale. Ch allenges in urban information extraction and management for solar PV deployment assessment are determined and quantified. First, a comprehensive examination and comparisons of existing

[4] Olz, S.; Sims, R.; Kirchner, N. Contribution of Renewables to Energy Security. IEA INFORMATION Paper. 2007. Available online: http://www.iea.org/papers/2007/so_contri bution.pdf (accessed on 17 March 2011).

[5] Wong, J.L. Getting out of the shade: Solar energy as a National Security Strategy. China Secur. 2009, 5, 88 100.

[6] Branker, K.; Pearce, J.M. Financial return for government support of large - scale thin film solar photovoltaic manufacturing in Canada. Energy Policy 2010, 38, 4291 4303.

[7] Myrans, K. Comparative Energy and Carbon Assessment of Three Green Technologies for a Toronto Roof. M.Sc. T hesis, University of Toronto, Toronto, ON, Canada, 2009.

[8] Fthenakis, V.M.; Kim, H.C.; Alsema, E. Emissions from photovoltaic life cycles. Environ. Sci. Technol. 2008, 42, comprehensive examination and comparisons of existing

algorithms and approaches to turn LiDAR point cloud into 2.5D urban sce nes was provided. A more cross - disciplinarily transparent methodology that attains a 95% accurate segmentation from raw and randomly chosen data was demonstrated. The methodology implements what previous literature recommends in terms of integrating cross disciplinary competences in remote sensing, GIS, computer vision and urban environmental studies. It is a robust methodology that can work with poor - quality data and reconstruct vegetation and building separately but concurrently. Since the coarse selectio n of building regions is crucial to reliable results considerable attention was focused on this first step.The approach was data driven hence the whole attempt can be regarded as a large scale optimization problem aiming at best approximating the point clo ud. Singular Value Decomposition, Random Sample Consensus and Triangular Irregular Network were confirmed as essential tools for the task. Rules of thumb were collected to

photovoltaic life cycles. Environ. Sci. Technol. 2008, 42, 2168 2174.

[9] Supported R&D Activities in the Field of Photovoltaics. In Proceedings of the 28th IEEE Photovoltaic Specialists Conference , Anchorage, AK, USA, 151734 1735.

[10] Cameron, M. The changing landscape of the global solar electricity market: Opportunities and challenges for European Industry. Photovolt. Bull. 2003 , 2003, 68.

[11] Hoffman, W. PV solar ele ctricity industry: Market growth and perspective. Sol. Energy Mater. Sol. Cells 2006, 90, 3285 3311.

[12] Frankl, P.; Nowak, S.; Gutschner, M.; Gnos, S. Technology Roadmap -Solar Photovoltaic Energy; International Energy Agency: Paris, France, 2010; pp. 1 48.

tools for the task. Rules of thumb were collected to

incorporate in the development of such scripts for extracting rooftops for solar pho tovoltaic potential. But there is still room for the more mathematically rigorous or biologically minded audience to contribute and orient the workflow to suit their needs. Hence this can be regarded as the next step towards a new generation of urban analysis software.