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Optimising 2-parameter Lambert Conformal Conic projections for ground-to-grid distortions / Sergio Baselga in Survey review, Vol 53 n° 380 (September 2021)  

Public [article]  inSurvey review > Vol 53 n° 380 (September 2021) . - pp 415 - 421 Titre : Optimising 2-parameter Lambert Conformal Conic projections for ground-to-grid distortions Type de document : Article/Communication Auteurs : Sergio Baselga, Auteur Année de publication : 2021 Article en page(s) : pp 415 - 421 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Projections [Termes IGN] carroyage géographique [Termes IGN] déformation géométrique [Termes IGN] projection conique de Lambert [Termes IGN] projection Universal Transverse Mercator [Termes IGN] transformation inverse Résumé : (auteur) A Lambert Conformal Conic (LCC) projection with two true-scale parallels of latitudes ϕl and ϕu can be recast in a LCC projection with one standard parallel of latitude ϕ0 and scale k0, having the practical advantage that the same type of definition can be used for the two conformal projections universally used: LCC and Transverse Mercator (TM). While equations giving ϕ0 and k0 in terms ϕl and ϕu can be found in the literature, inverse relationships are not readily found. They are derived in the present paper. These may be necessary in views of the planned future definition of the United States State Plane Coordinate System (SPCS) 2022 for the users of particular mapping software requiring to specify the two latitude values instead of the central latitude and central scale. While map projection parameters are customary selected to minimise ellipsoid-to-grid distortions for a region, in some cases it could be more convenient to study and minimise ground-to-grid distortions. Also bearing in mind the design of SPCS 2022, we discuss the advantages and disadvantages of working with each type of distortion definition. Numéro de notice : A2021-638 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2020.1797339 Date de publication en ligne : 28/07/2020 En ligne : https://doi.org/10.1080/00396265.2020.1797339 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98305 [article]

Deformation monitoring of the submillimetric UPV calibration baseline / Luis García-Asenjo in Journal of applied geodesy, vol 11 n° 2 (June 2017)  

Public [article]  inJournal of applied geodesy > vol 11 n° 2 (June 2017) . - pp 107 - 114 Titre : Deformation monitoring of the submillimetric UPV calibration baseline Type de document : Article/Communication Auteurs : Luis García-Asenjo, Auteur ; Sergio Baselga, Auteur ; Pascual Garrigues, Auteur Année de publication : 2017 Article en page(s) : pp 107 - 114 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] base géodésique [Termes IGN] déformation géométrique [Termes IGN] distancemètre [Termes IGN] étalonnage d'instrument [Termes IGN] mécomètre [Termes IGN] stabilité [Termes IGN] Valence (Espagne) Résumé : (Auteur) A 330 m calibration baseline was established at the Universitat Politècnica de València (UPV) in 2007. Absolute scale was subsequently transferred in 2012 from the Nummela Standard Baseline in Finland and distances between pillars were determined with uncertainties ranging from 0.1 mm to 0.3 mm. In order to assess the long-term stability of the baseline, three field campaigns were carried out from 2013 to 2015 in a co-operative effort with the Universidad Complutense de Madrid (UCM), which provided the only Mekometer ME5000 distance meter available in Spain. Since the application of the ISO17123-4 full procedure did not suffice to come to a definite conclusion about possible displacements of the pillars, we opted for the traditional geodetic network approach. This approach had to be adapted to the case at hand in order to deal with problems such as the geometric weakness inherent to calibration baselines and scale uncertainty derived from both the use of different instruments and the high correlation between the meteorological correction and scale determination. Additionally, the so-called the maximum number of stable points method was also tested. In this contribution, it is described the process followed to assess the stability of the UPV submillimetric calibration baseline during the period of time from 2012 to 2015. Numéro de notice : A2017-284 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0018 En ligne : https://doi.org/10.1515/jag-2016-0018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85317 [article]