{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T03:16:44Z","timestamp":1781666204688,"version":"3.54.5"},"reference-count":52,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2020,3,11]],"date-time":"2020-03-11T00:00:00Z","timestamp":1583884800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJGI"],"abstract":"<jats:p>Unmanned aerial vehicle (UAV) systems are heavily adopted nowadays to collect high-resolution imagery with the purpose of documenting and mapping environment and cultural heritage. Such data are currently processed by programs based on the Structure from Motion (SfM) concept, coming from the computer vision community, rather than from classical photogrammetry. It is interesting to check whether some widely accepted rules coming from old-fashioned photogrammetry still holds: the relation between accuracy and ground sampling distance (GSD), the ratio between the vertical and horizontal accuracy, accuracy estimated on ground control points (GCPs) vs. that estimated with check points (CPs) also in relation to their ratio and distribution. To face the envisaged aspects, the paper adopts a comparative approach, as several programs are used and numerous configurations considered. The paper illustrates the dataset adopted, the carefully tuned processing strategies and bundle block adjustment (BBA) results in terms of accuracy for both GCPs and CPs. Finally, a leave-one-out (LOO) cross-validation strategy is proposed to assess the accuracy for one of the proposed configurations. Some of the reported results were previously presented in the 5th GISTAM Conference.<\/jats:p>","DOI":"10.3390\/ijgi9030164","type":"journal-article","created":{"date-parts":[[2020,3,12]],"date-time":"2020-03-12T04:13:57Z","timestamp":1583986437000},"page":"164","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":47,"title":["Accuracy Assessment of a UAV Block by Different Software Packages, Processing Schemes and Validation Strategies"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2086-7931","authenticated-orcid":false,"given":"Vittorio","family":"Casella","sequence":"first","affiliation":[{"name":"Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata, 3, 27100 Pavia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4982-5236","authenticated-orcid":false,"given":"Filiberto","family":"Chiabrando","sequence":"additional","affiliation":[{"name":"Department of Architecture and Design, Polytechnic of Turin, Viale Pier Andrea Mattioli, 39, 10125 Turin, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3921-5178","authenticated-orcid":false,"given":"Marica","family":"Franzini","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata, 3, 27100 Pavia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ambrogio Maria","family":"Manzino","sequence":"additional","affiliation":[{"name":"Department of Environment, Land and Infrastructure Engineering, Polytechnic of Turin, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"L\u00fctjens, M., Kersten, T.P., Dorschel, B., and Tschirschwitz, F. 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