Abstract
Land cover, as the direct description of the Earth surface, has close relationships to the circle of global substances and energy, climate change, and economic activities of human society. The acquisition of land cover products is usually based on image classification. The accuracy of image classification is highly important to the monitoring and investigation of global environment as well as in decision-making support. Thus, classification accuracy assessment of land cover products is an important procedure. Given that many mixed pixels are located in between different classes, the accuracy of edge pixels tend to be lower than that of interior pixels. This scenario leads to the increment of heterogeneity to the classification accuracy of each class and to the increase of uncertainty of accuracy assessment. This study presents a method named stratified sampling considering edges (SSCE) based on traditional stratified sampling (SS) to optimize the process of classification accuracy assessment. Theoretical derivations and experimental results indicate that SSCE has high stability and accuracy on the estimation of overall accuracy and kappa. SSCE has high accuracy on estimating classification accuracy when only a few sampling points exist. SSCE needs less sampling points than SS under the same tolerance of error. The higher the difference on accuracy is and the more equal the areas between edge regions and interior regions are, the more accurate SSCE is on accuracy assessment. In a word, SSCE costs minimal sampling points. It also has high accuracy and stability on the assessment of land cover classification accuracy.
Similar content being viewed by others
References
Chen J, Chen J, Liao A, Cao X, Chen L, Chen X, He C, Han G, Peng S, Lu M, Zhang W, Tong X, Mills J. 2015. Global land cover mapping at 30 m resolution: A POK-based operational approach. ISPRS-J Photogramm Remote Sens, 103: 7–27
Chen J, Zhu X, Imura H, Chen X. 2010. Consistency of accuracy assessment indices for soft classification: Simulation analysis. ISPRS-J Photogramm Remote Sens, 65: 156–164
Chen X H, Chen J, Jia X P, Somers B, Wu J, Coppin P. 2011. A quantitative analysis of virtual endmembers’ increased impact on the collinearity effect in spectral unmixing. IEEE Trans Geosci Remote Sensing, 49: 2945–2956
Cohen J. 1960. A coefficient of agreement for nominal scale. Educ Psychol Meas, 20: 37–46
Congalton R G. 1988. Using spatial autocorrelation analysis to explore the errors in maps generated from remotely sensed data. Photogramm Eng Remote Sens, 54: 587–592
Foody G M. 2002. Status of land cover classification accuracy assessment. Remote Sens Environ, 80: 185–201
Hammond T O, Verbyla D L. 1996. Optimistic bias in classification accuracy assessment. Int J Remote Sens, 17: 1261–1266
Hansen M C, Potapov P V, Moore R, Hancher M, Turubanova S A, Tyukavina A, Thau D, Stehman S V, Goetz S J, Loveland T R, Kommareddy A, Egorov A, Chini L, Justice C O, Townshend J R G. 2013. High-resolution global maps of 21st-century forest cover change. Science, 342: 850–853
Jin Y, Du Z, Jiang Y. 2008. Sampling Technique (in Chinese). Beijing: China Renmin University Press. 66
Khan M, Rao D, Ansari A H, Ahsan M J. 2015. Determining optimum strata boundaries and sample sizes for Skewed population with log-normal distribution. Commun Stat-Simul C, 44: 1364–1387
Li B, Fang X, Ye Y, Zhang X. 2010. Accuracy assessment of global historical cropland datasets based on regional reconstructed historical data—A case study in Northeast China. Sci China Earth Sci, 53: 1689–1699
Li X, He H S, Bu R, Wen Q, Chang Y, Hu Y, Li Y. 2005. The adequacy of different landscape metrics for various landscape patterns. Pattern Recognit, 38: 2626–2638
Liao A, Chen L, Chen J, He C, Cao X, Chen J, Peng S, Sun F, Gong P. 2014. High-resolution remote sensing mapping of global land water. Sci China Earth Sci, 57: 2305–2316
Liu C, Frazier P, Kumar L. 2007. Comparative assessment of the measures of thematic classification accuracy. Remote Sens Environ, 107: 606–616
Olofsson P, Foody G M, Herold M, Stehman S V, Woodcock C E, Wulder M A. 2014. Good practices for estimating area and assessing accuracy of land change. Remote Sens Environ, 148: 42–57
Olofsson P, Foody G M, Stehman S V, Woodcock C E. 2013. Making better use of accuracy data in land change studies: Estimating accuracy and area and quantifying uncertainty using stratified estimation. Remote Sens Environ, 129: 122–131
Särndal C, Swensson B, Wretman J. 2003. Model Assisted Survey Sampling. New York: Springer Science & Business Media. 418
Stehman S V. 2009. Sampling designs for accuracy assessment of land cover. Int J Remote Sens, 30: 5243–5272
Stehman S V. 2012. Impact of sample size allocation when using stratified random sampling to estimate accuracy and area of land-cover change. Remote Sens Lett, 3: 111–120
Stehman S V, Wickham J D, Smith J H, Yang L. 2003. Thematic accuracy of the 1992 National Land-Cover Data for the Eastern United States: Statistical methodology and regional results. Remote Sens Environ, 86: 500–516
Sweeney S P, Evans T P. 2012. An edge-oriented approach to thematic map error assessment. Geocarto Int, 27: 31–56
Turner B L, Skole D L, Sanderson S, Fischer G, Fresco L, Leemans R. 1995. Land-Use and Land-Cover Change. In: IGBP Global Change Report No. 35. Stockholm: International Geosphere-Biosphere Programme
Zell E, Huff A K, Carpenter A T, Friedl L A. 2012. A user-driven approach to determining critical earth observation priorities for societal benefit. IEEE J-Stars, 5: 1594–1602
Zhu P, Gong P. 2014. Suitability mapping of global wetland areas and validation with remotely sensed data. Sci China Earth Sci, 57: 2283–2292
Acknowledgements
This work was supported by the National High-Tech Research Program of China (Grant No. 2013AA122802).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Liu, M., Cao, X., Li, Y. et al. Method for land cover classification accuracy assessment considering edges. Sci. China Earth Sci. 59, 2318–2327 (2016). https://doi.org/10.1007/s11430-016-5333-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11430-016-5333-5