{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T21:31:12Z","timestamp":1781299872532,"version":"3.54.1"},"reference-count":47,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,11,26]],"date-time":"2020-11-26T00:00:00Z","timestamp":1606348800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001659","name":"Deutsche Forschungsgemeinschaft","doi-asserted-by":"publisher","award":["SPP 1894"],"award-info":[{"award-number":["SPP 1894"]}],"id":[{"id":"10.13039\/501100001659","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJGI"],"abstract":"<jats:p>Social media data is heavily used to analyze and evaluate situations in times of disasters, and derive decisions for action from it. In these critical situations, it is not surprising that privacy is often considered a secondary problem. In order to prevent subsequent abuse, theft or public exposure of collected datasets, however, protecting the privacy of social media users is crucial. Avoiding unnecessary data retention is an important question that is currently largely unsolved. There are a number of technical approaches available, but their deployment in disaster management is either impractical or requires special adaption, limiting its utility. In this case study, we explore the deployment of a cardinality estimation algorithm called HyperLogLog into disaster management processes. It is particularly suited for this field, because it allows to stream data in a format that cannot be used for purposes other than the originally intended. We develop and conduct a focus group discussion with teams of social media analysts. We identify challenges and opportunities of working with such a privacy-enhanced social media data format and compare the process with conventional techniques. Our findings show that, with the exception of training scenarios, deploying HyperLogLog in the data acquisition process will not distract the data analysis process. Instead, several benefits, such as improved working with huge datasets, may contribute to a more widespread use and adoption of the presented technique, which provides a basis for a better integration of privacy considerations in disaster management.<\/jats:p>","DOI":"10.3390\/ijgi9120709","type":"journal-article","created":{"date-parts":[[2020,11,26]],"date-time":"2020-11-26T09:04:15Z","timestamp":1606381455000},"page":"709","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Case Study on Privacy-Aware Social Media Data Processing in Disaster Management"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6751-5496","authenticated-orcid":false,"given":"Marc","family":"L\u00f6chner","sequence":"first","affiliation":[{"name":"Institute of Cartography, Technische Universit\u00e4t Dresden, Helmholtzstr. 10, 01062 Dresden, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3652-3244","authenticated-orcid":false,"given":"Ramian","family":"Fathi","sequence":"additional","affiliation":[{"name":"Institute for Public Safety and Emergency Management, Bergische Universit\u00e4t Wuppertal, Gau\u00dfstr. 20, 42119 Wuppertal, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8453-5026","authenticated-orcid":false,"given":"David \u2018-1\u2019","family":"Schmid","sequence":"additional","affiliation":[{"name":"Institute for Visualization and Interactive Systems, Universit\u00e4t Stuttgart, Universit\u00e4tstra\u00dfe 38, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1157-7967","authenticated-orcid":false,"given":"Alexander","family":"Dunkel","sequence":"additional","affiliation":[{"name":"Institute of Cartography, Technische Universit\u00e4t Dresden, Helmholtzstr. 10, 01062 Dresden, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2949-4887","authenticated-orcid":false,"given":"Dirk","family":"Burghardt","sequence":"additional","affiliation":[{"name":"Institute of Cartography, Technische Universit\u00e4t Dresden, Helmholtzstr. 10, 01062 Dresden, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frank","family":"Fiedrich","sequence":"additional","affiliation":[{"name":"Institute for Public Safety and Emergency Management, Bergische Universit\u00e4t Wuppertal, Gau\u00dfstr. 20, 42119 Wuppertal, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steffen","family":"Koch","sequence":"additional","affiliation":[{"name":"Institute for Visualization and Interactive Systems, Universit\u00e4t Stuttgart, Universit\u00e4tstra\u00dfe 38, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,26]]},"reference":[{"key":"ref_1","unstructured":"Koeze, E., and Popper, N. (2020, November 25). The Virus Changed the Way We Internet. Available online: https:\/\/www.nytimes.com\/interactive\/2020\/04\/07\/technology\/coronavirus-internet-use.html."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1111\/1468-5973.12196","article-title":"Fifteen Years of Social Media in Emergencies: A Retrospective Review and Future Directions for Crisis Informatics","volume":"26","author":"Reuter","year":"2018","journal-title":"J. Conting. Crisis Manag."},{"key":"ref_3","unstructured":"Kuner, C., and Marelli, M. (2020). Social Media. Handbook on Data Protection in Humanitarian Action, International Committee of the Red Cross."},{"key":"ref_4","unstructured":"Rouse, M. (2020, November 25). Data Retention. Available online: https:\/\/searchstorage.techtarget.com\/definition\/data-retention."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Fiesler, C., Beard, N., and Keegan, B.C. (2020, January 8\u201311). No robots, spiders, or scrapers: Legal and ethical regulation of data collection methods in social media terms of service. Proceedings of the International AAAI Conference on Web and Social Media, Atlanta Georgia, GA, USA.","DOI":"10.1609\/icwsm.v14i1.7290"},{"key":"ref_6","unstructured":"Miller, V. (2020). Understanding Digital Culture, SAGE Publications Limited."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Dunkel, A., L\u00f6chner, M., and Burghardt, D. (2020). Privacy-Aware Visualization of Volunteered Geo-Graphic Information (Vgi) to Analyze Spatial Activity: A Benchmark Implementation. ISPRS Int. J. Geo-Inf., 9.","DOI":"10.3390\/ijgi9100607"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1080\/10447318.2018.1427832","article-title":"Social Media in Crisis Management: An Evaluation and Analysis of Crisis Informatics Research","volume":"34","author":"Reuter","year":"2018","journal-title":"Int. J. Hum. Comput. Interact."},{"key":"ref_9","unstructured":"St Denis, L.A., Hughes, A.L., and Palen, L. (2012, January 22\u201325). Trial by fire: The deployment of trusted digital volunteers in the 2011 shadow lake fire. Proceedings of the 9th International ISCRAM Conference, Vancouver, BC, Canada."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Castillo, C. (2016). Big Crisis Data: Social Media in Disasters and Time-Critical Situations, Cambridge University Press. [1st ed.]. Cambridge University.","DOI":"10.1017\/CBO9781316476840"},{"key":"ref_11","unstructured":"(2020, November 25). Statista Global Consumer Survey Umfrage in Deutschland zu beliebten Arten von Social Media 2020: Welche Arten von Social Media nutzen Sie regelm\u00e4\u00dfig?. Available online: https:\/\/de.statista.com\/prognosen\/999854\/umfrage-in-deutschland-zu-beliebten-arten-von-social-media."},{"key":"ref_12","unstructured":"(2020, November 25). Bitkom e.V Social-Media-Nutzung Steigt durch Corona stark an. Available online: https:\/\/www.bitkom.org\/Presse\/Presseinformation\/Social-Media-Nutzung-steigt-durch-Corona-stark-an."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Reuter, C. (2018). Einbindung ungebundener Helfer in die Bew\u00e4ltigung von Schadensereignissen. Sicherheitskritische Mensch-Computer-Interaktion, Springer.","DOI":"10.1007\/978-3-658-19523-6"},{"key":"ref_14","first-page":"1","article-title":"Organisation von Spontanhelfern am Beispiel des Starkregenereignisses vom 28.07. 2014 in M\u00fcnster","volume":"2","author":"Fathi","year":"2017","journal-title":"Notfallvorsorge"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4787","DOI":"10.1038\/s41467-018-06930-7","article-title":"The Spread of Low-Credibility Content by Social Bots","volume":"9","author":"Shao","year":"2018","journal-title":"Nat. Commun."},{"key":"ref_16","unstructured":"Starbird, K., Maddock, J., Orand, M., Achterman, P., and Mason, R.M. (2014). Rumors, False Flags, and Digital Vigilantes: Misinformation on Twitter after the 2013 Boston Marathon Bombing. iConference 2014 Proceedings, iSchools."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/3415211","article-title":"Countering Fake News: A Comparison of Possible Solutions Regarding User Acceptance and Effectiveness","volume":"4","author":"Kirchner","year":"2020","journal-title":"Proc. ACM Hum.-Comput. Interact."},{"key":"ref_18","unstructured":"(2020, November 25). World Health Organization Novel Coronavirus(2019-nCoV): Situation Report 13. Available online: https:\/\/www.who.int\/docs\/default-source\/coronaviruse\/situation-reports\/20200202-sitrep-13-ncov-v3.pdf."},{"key":"ref_19","unstructured":"Vieweg, S., Palen, L., Liu, S.B., Hughes, A., and Sutton, J. (2008). Collective Intelligence in Disaster: Examination of the Phenomenon in the Aftermath of the 2007 Virginia Tech Shooting, University of Colorado."},{"key":"ref_20","unstructured":"Imran, M., Castillo, C., Lucas, J., Meier, P., and Vieweg, S. (2014, January 11). AIDR\u2014 Artificial intelligence for disaster response. Proceedings of the 23rd International Conference on World Wide Web, Seoul, Korea."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/2771588","article-title":"Processing Social Media Messages in Mass Emergency","volume":"47","author":"Imran","year":"2015","journal-title":"ACM Comput. Surv."},{"key":"ref_22","unstructured":"Leysia, P., Sarah, V., Jeannette, S., Sophia, B., and Liu, A.H. (2007, January 4\u20139). Crisis Informatics: Studying Crisis in a Networked World. Proceedings of the Third International Conference on E-Social Science, Ann Arbor, MI, USA."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s41018-016-0013-9","article-title":"Crisis Analytics: Big Data-Driven Crisis Response","volume":"1","author":"Qadir","year":"2016","journal-title":"J. Int. Humanit. Action"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1007\/s10708-007-9111-y","article-title":"Citizens as Sensors: The World of Volunteered Geography","volume":"69","author":"Goodchild","year":"2007","journal-title":"GeoJournal"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1080\/17538941003759255","article-title":"Crowdsourcing Geographic Information for Disaster Response: A Research Frontier","volume":"3","author":"Goodchild","year":"2010","journal-title":"Int. J. Digit. Earth"},{"key":"ref_26","first-page":"1","article-title":"Descriptive and Visual Summaries of Disaster Events Using Artificial Intelligence Techniques: Case Studies of Hurricanes Harvey, Irma, and Maria","volume":"3","author":"Alam","year":"2019","journal-title":"Behav. Inf. Technol."},{"key":"ref_27","first-page":"203","article-title":"Social Media in Crisis: When Professional Responders Meet Digital Volunteers","volume":"12","author":"Hughes","year":"2015","journal-title":"J. Homel. Secur. Emerg. Manag."},{"key":"ref_28","unstructured":"Comes, T., Vybornova, O., and Van de Walle, B. (2015, January 23\u201325). Bringing structure to the disaster data typhoon: An analysis of decision-makers\u2019 information needs in the response to haiyan. Proceedings of the AAAI Spring Symposium, Stanford, CA, USA."},{"key":"ref_29","unstructured":"Reuter, C. (2018). Sicherheitskritische Mensch-Computer-Interaktion: Interaktive Technologien und soziale Medien im Krisen- und Sicherheitsmanagement, Springer Vieweg."},{"key":"ref_30","first-page":"1","article-title":"Lageinformationen Aus Den Sozialen Netzwerken: Virtual Operations Support Teams (Vost) International Im Einsatz","volume":"49","author":"Fathi","year":"2018","journal-title":"Notfallvorsorge"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/j.ipm.2019.102174","article-title":"VOST: A Case Study in Voluntary Digital Participation for Collaborative Emergency Management","volume":"57","author":"Fathi","year":"2020","journal-title":"Inf. Process. Manag."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"119724","DOI":"10.1016\/j.techfore.2019.119724","article-title":"The Impact of Risk Cultures: Citizens\u2019 Perception of Social Media Use in Emergencies Across Europe","volume":"148","author":"Reuter","year":"2019","journal-title":"Technol. Forecast. Soc. Chang."},{"key":"ref_33","unstructured":"Polous, K. (2016). Event Cartography: A New Perspective in Mapping. [Ph.D. Thesis, Technische Universit\u00e4t M\u00fcnchen]."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1080\/01972240252818216","article-title":"Data Retention and the Panoptic Society: The Social Benefits of Forgetfulness","volume":"18","author":"Blanchette","year":"2002","journal-title":"Inf. Soc."},{"key":"ref_35","unstructured":"Leetaru, K. (2020, November 25). The Era of Precision Mapping of Social Media Is Coming to an End. Available online: https:\/\/web.archive.org\/web\/20191219100123\/https:\/\/www.forbes.com\/sites\/kalevleetaru\/2019\/03\/06\/the-era-of-precision-mapping-of-social-media-is-coming-to-an-end\/."},{"key":"ref_36","first-page":"965","article-title":"The Right to Information Self-Determination","volume":"2001","author":"Eberle","year":"2001","journal-title":"Utah Law Rev."},{"key":"ref_37","unstructured":"Kuner, C., and Marelli, M. (2020). Data Analytics and Big Data. Handbook on Data Protection in Humanitarian Action, International Committee of the Red Cross."},{"key":"ref_38","unstructured":"Samarati, P., and Sweeney, L. (2020, November 25). Protecting Privacy When Disclosing Information: K-Anonymity and Its Enforcement Through Generalization and Suppression. Available online: https:\/\/epic.org\/privacy\/reidentification\/Samarati_Sweeney_paper.pdf."},{"key":"ref_39","unstructured":"Dwork, C. (2008, January 13\u201316). Differential privacy: A survey of results. Proceedings of the International Conference on Theory and Applications of Models of Computation, Kitakyushu, Japan."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"104987","DOI":"10.1016\/j.knosys.2019.104987","article-title":"Probabilistic Data Structures for Big Data Analytics: A Comprehensive Review","volume":"188","author":"Singh","year":"2020","journal-title":"Knowl.-Based Syst."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Flajolet, P., Fusy, \u00c9., Gandouet, O., and Meunier, F. (2007, January 7\u201312). Hyperloglog: The analysis of a near-optimal cardinality estimation algorithm. Proceedings of the Discrete Mathematics and Theoretical Computer Science, Dijon, France.","DOI":"10.46298\/dmtcs.3545"},{"key":"ref_42","first-page":"26","article-title":"Cardinality Estimators Do Not Preserve Privacy","volume":"2019","author":"Desfontaines","year":"2019","journal-title":"Proc. Priv. Enhanc. Technol."},{"key":"ref_43","unstructured":"L\u00f6chner, M., Dunkel, A., and Burghardt, D. (2019, January 8\u20139). Protecting Privacy Using Hyperloglog to Process Data from Location Based Social Networks. Proceedings of the Legal Ethical factorS crowdSourced geOgraphic iNformation 2019: 1st International Workshop on Legal and Ethical Issues in Crowdsourced Geographic Information, Z\u00fcrich, Switzerland."},{"key":"ref_44","unstructured":"Krumpe, F., Dunkel, A., and L\u00f6chner, M. (2020, November 25). LBSN Structure. Available online: https:\/\/pypi.org\/project\/lbsnstructure\/."},{"key":"ref_45","unstructured":"Pr\u00fcfer, P., and Rexroth, M. (1996). Verfahren zur Evaluation von Survey-Fragen: Ein \u00dcberblick, Social Science Open Access Repository."},{"key":"ref_46","unstructured":"Dunkel, A. (2020, November 25). Lbsntransform. Available online: https:\/\/pypi.org\/project\/lbsntransform\/."},{"key":"ref_47","unstructured":"Chen, X., Pival, P.R., Cirik, A., and Mohajerani, S. (2020, November 25). Many More Awesome Public Datasets. Available online: https:\/\/github.com\/awesomedata\/awesome-public-datasets."}],"container-title":["ISPRS International Journal of Geo-Information"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2220-9964\/9\/12\/709\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:37:50Z","timestamp":1760179070000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2220-9964\/9\/12\/709"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,11,26]]},"references-count":47,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2020,12]]}},"alternative-id":["ijgi9120709"],"URL":"https:\/\/doi.org\/10.3390\/ijgi9120709","relation":{},"ISSN":["2220-9964"],"issn-type":[{"value":"2220-9964","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,11,26]]}}}