Drag Perko's main area of research is the classification of landscape units using GIS. He has produced several landscape typologies of Slovenia, the most widely accepted of which is from 1995 (last updated in 2021) with 12 types. Other important areas of his research are geomorphometry and geographical names.

He has led numerous projects. Among the most important are the applied projects Determination of Natural Landscape Types in Slovenia Using a GIS (2010–2013), Landscape Diversity and Hotspots of Slovenia (2014–2017), and Geographical Basis for the Arbitration Procedure for Determining the Slovenian-Croatian Border (2011–2012).
He co-founded the book series Geography of Slovenia (1999), Georitem (2007), GIS in Slovenia (1992), and Regional Development (2007). Between 1999 and 2007, he was the editor of the journal Geografski vestnik, and since 2011 he has been the executive editor of the journal Acta geographica Slovenica. He is a member of several editorial boards of Slovenian and European publications.

He is the co-author and co-editor of extensive fundamental geographic works on Slovenia: Gazetteer of Slovenian Places (1995), Geographical Atlas of Slovenia (1998), Slovenia: Landscapes and People (1998), National Atlas of Slovenia (2001), the facsimile of Atlant, the first world atlas in Slovenian (2006), Census Atlas of Slovenia 2002 (2007), Slovenia in Focus (2008), Terraced Landscapes (2017), and The Geography of Slovenia: Small but Diverse (2020).
 

Education
B. Sc. in Geography and Sociology, Faculty of Arts, University of Ljubljana, 1985
M. Sc. in Geography, Faculty of Arts, University of Ljubljana, 1989
Ph. D. in Geography, Faculty of Arts, University of Ljubljana, 1993

• Perko, D. 2023: The first world atlas in Slovenian, and Slovenian territory in some early world atlases. Acta geographica Slovenica 63-2.
• Perko, D., Ciglič, R., Hrvatin, M. 2021: Landscape macrotypologies and microtypologies of Slovenia. Acta geographica Slovenica 61-3.
• Perko, D., Ciglič, R. 2020: Slovenia's landscapes. The geography of Slovenia: small but diverse. Springer, Cham.
• Ciglič, R., Štrumbelj, E., Češnovar, R., Hrvatin, M., Perko, D. 2019: Evaluating existing manually constructed natural landscape classification with a machine learning-based approach. Journal of Spatial Information Science 18.
• Perko, D., Ciglič, R., Hrvatin, M. 2019: The usefulness of unsupervised classification methods for landscape typification: the case of Slovenia. Acta geographica Slovenica 59-2.
• Perko, D., Zorn, M., Ciglič, R., Breg Valjavec, M. 2019: Changing river courses and border determination challenges: the case of the Slovenian-Croatian Border. Geospatial challenges in the 21st century. Springer, Cham.
• Ciglič, R., Perko, D. 2017: A method for evaluating raster data layers according to landscape classification scale. Ecological informatics 39.
• Perko, D., Hrvatin, M., Ciglič, R. 2017: Determination of landscape hotspots of Slovenia. Acta geographica Slovenica 57-1.
• Perko, D., Hrvatin, M., Ciglič, R. 2015: A methodology for natural landscape typification of Slovenia. Acta geographica Slovenica 55-2.
• Perko, D., Ciglič, R. 2015: Slovenia as a European landscape hotspot. Acta Geobalcanica 1-2.
• Ciglič, R., Perko, D. 2015: Modelling as a Method for Evaluating Natural Landscape Typology: The Case of Slovenia. Landscape Analysis and Planning. Springer, Heidelberg.
• Ciglič, R., Perko, D. 2013: Europe's landscape hotspots. Acta geographica Slovenica 53-1.

• Geography of Slovenia - national research programme (research programme • January 1, 2022 - December 31, 2027)
• Advancement of computationally intensive methods for efficient modern general-purpose statistical analysis and inference (applied project • March 1, 2016 - February 28, 2019)
• Terraced Landscapes (applied project • December 1, 2004 - December 31, 2007)
• Determination of natural landscape types at local level (November 1, 2013 - June 30, 2015)
• Landscape diversity and hotspots of Slovenia (applied project • October 1, 2014 - February 28, 2018)
• Standardization of hydronyms in the Register of geographical names (target research project • September 1, 2021 - August 31, 2024)
• The Life and Death of Cultivated Terraces: Computer-Based Recognition and Spatial Analysis of Terraces (applied research project • January 1, 2025 - December 31, 2027)

• ZRC SAZU Researcher Emeritus title, 2025
• Gold Tablet of the Association of the Geographical Societies of Slovenia, 2022
• Silver Tablet of the Association of the Geographers of Slovenia, 2009
• Vajgl Award for Master's degree thesis, 1989
• ZRC SAZU Gold Award, 1999
• Bronze Tablet of the Association of the Geographical Societies of Slovenia, 1997
• Kidrič Award for undergraduate study, University of Ljubljana, 1986
• Prešeren Student Award, Faculty of Arts, University of Ljubljana, 1986

• Member of the Commission for the Standardization of Geographical Names of the Government of the Republic of Slovenia (since 1995)
• Chair of the ZRC SAZU Board of Directors (since 2019)
• Executive editor of the Acta geographica Slovenica journal (since 2011)
• Coeditor of the Geography of Slovenia book series (since 1999)
• Coeditor of the Georhythm book series (since 2007)
• Coeditor of the GIS in Slovenia book series (since 1992)
• Coeditor of the CAPACities book series (od 2010)
• Member of the Thought, society, culture book series editorial board, Peter Lang Verlag, Frankfurt am Main (since 2013)
• Member of the Acta geographica Slovenica journal editorial board (since 1995)
• Member of the Geografski vestnik (Geographical Bulletin) journal editorial board (since 1999)
• Member of the Acta Geobalcanica journal editorial board (since 2015)
• Member of the National Geographic Slovenia editorial board (since 2006)
• Member of the scientific committee of the Geographic Information System in Slovenia (since 1991), the Regional development in Slovenia (since 2007), the Natural Hazards in Slovenia (since 2008) symposiums