METHODOLOGY FOR THE EXTRACTION OF HOMOLOGOUS POINTS FROM A DEM/DSM TO EVALUATE THE RELATIVE POSITIONAL ACCURACY

This work presents a new methodology for extracting 3D homologous points from a DEM/DSM for relative evaluation of positional accuracies, from terrain features such as ridgelines and hydrography. Firstly, it extracts 3D intersection points between the linear features and then it performs a selection of these homologous points. A discussion regarding the spatial resolution effect of the DEM/DSM on the proposed methodology is carried out. As case study, the planimetric and altimetric positional accuracies evaluation of SRTM (X-band) and Aster GDEM (version 2) DSMs was conducted using, as reference, a DSM obtained via photogrammetry. The SRTM and Aster GDEM (version 2) DSMs showed similar classifications, that is, Class A for the altimetry and Class B for the planimetry at the 1:100,000 scale, according to the Brazilian technical standard of positional accuracy.

Keywords:
positional accuracy; DSM; DEM; homologous point extraction; spatial data quality

Authorship

Afonso de Paula dos Santos

Universidade Federal de Viçosa - UFV, Departamento Eng. Civil, Setor de Eng. de Agrimensura e Cartográfica, Viçosa - MG, Brasil. E-mail: afonso.santos@ufv.br; nilcilene.medeiros@ufv.br; dalto@ufv.brUniversidade Federal de ViçosaBrazilViçosa, MG, BrazilUniversidade Federal de Viçosa - UFV, Departamento Eng. Civil, Setor de Eng. de Agrimensura e Cartográfica, Viçosa - MG, Brasil. E-mail: afonso.santos@ufv.br; nilcilene.medeiros@ufv.br; dalto@ufv.br

http://orcid.org/0000-0001-7248-4524

Nilcilene das Graças Medeiros

http://orcid.org/0000-0003-0839-3729

Aluir Porfírio Dal Poz

Universidade Estadual Paulista - UNESP, Faculdade de Ciência e Tecnologia, Departamento de Cartográfica, Presidente Prudente - SP, Brasil. E-mail: aluir.dal-poz@unesp.brUniversidade Estadual PaulistaBrazilPresidente Prudente, SP, BrazilUniversidade Estadual Paulista - UNESP, Faculdade de Ciência e Tecnologia, Departamento de Cartográfica, Presidente Prudente - SP, Brasil. E-mail: aluir.dal-poz@unesp.br

http://orcid.org/0000-0002-2534-1229

Gérson Rodrigues dos Santos

Universidade Federal de Viçosa - UFV, Departamento de Estatística, Viçosa - MG, Brasil. E-mail: gerson.santos@ufv.br; paulo.emiliano@ufv.brUniversidade Federal de ViçosaBrazilViçosa, MG, BrazilUniversidade Federal de Viçosa - UFV, Departamento de Estatística, Viçosa - MG, Brasil. E-mail: gerson.santos@ufv.br; paulo.emiliano@ufv.br

http://orcid.org/0000-0002-4916-0908

Dalto Domingos Rodrigues

http://orcid.org/0000-0002-0325-8926

Paulo César Emiliano

http://orcid.org/0000-0002-1314-9002

AUTHOR´S CONTRIBUTION

Afonso Santos and Nilcilene Medeiros conceived of the presented idea. Afonso Santos developed the study, experiments and writing. All the authors contributed with preparation of draft manuscript, review of the proposed method, discussion of the results, data analysis, paper revision and refinement.

SCIMAGO INSTITUTIONS RANKINGS

Figures | Tables | Formulas

Figures (11)
Tables (4)
Formulas (2)

Class	Planimetry		Altimetry
Class	PEC	EP	PEC	EP
A	0.5 mm*E	0.3 mm*E	0.5*ci	0.33*ci
B	0.8 mm*E	0.5 mm*E	0.6*ci	0.4*ci
C	1.0 mm*E	0.6 mm*E	0.75*ci	0.5*ci

Statistics	SRTM-X		GDEM2
Statistics	d2D	dZ	d2D	dZ
No. Points	173	173	173	173
Average [m]	39.7	-10.3	42.0	4.9
RMS [m]	44.8	12.3	47.8	9.6
Minimum [m]	3.1	-35.4	1.9	-18.4
Maximum [m]	106.9	4.6	117.0	29.6

Component	Scale (Class)	PEC	EP	% (di ≤ PEC)	RMS(di) ≤ EP	Classification
Altimetric	1:100,000 (A)	25	16.7	98.3%	Attends	Approved
Planimetric	1:100,000 (A)	50	30	72.8%	Failed	Disapproved
Planimetric	1:100,000 (B)	80	50	96.5%	Attends	Approved