I'm doing pairwise LD calculation between my GWAS SNP and the surrounding SNPs, and Ihave three SNPs here, which is around 10kb upstream of my GWAS SNP; and the following are the R^2 and D'

         R^2     D'
SNP1    0.39    0.89
SNP2    0.33    0.72
SNP3    0.39    0.89

I'm wondering does the data here show these three SNPs are in strong LD with GWAS SNP? Why D' looks quite good while R^2 is not that good?

thanks!