1 files changed, 5 insertions, 2 deletions
diff --git a/src/projections/omerc.cpp b/src/projections/omerc.cpp
index 4d78fbef..c0278043 100644
--- a/src/projections/omerc.cpp
+++ b/src/projections/omerc.cpp
@@ -209,8 +209,11 @@ PJ *PROJECTION(omerc) {
             lam2 += M_TWOPI;
         P->lam0 = adjlon(.5 * (lam1 + lam2) - atan(
            J * tan(.5 * Q->B * (lam1 - lam2)) / p) / Q->B);
-        gamma0 = atan(2. * sin(Q->B * adjlon(lam1 - P->lam0)) /
-           (F - 1. / F));
+        const double denom = F - 1. / F;
+        if( denom == 0 ) {
+            return pj_default_destructor(P, PJD_ERR_INVALID_ECCENTRICITY);
+        }
+        gamma0 = atan(2. * sin(Q->B * adjlon(lam1 - P->lam0)) / denom);
         gamma = alpha_c = aasin(P->ctx, D * sin(gamma0));
     }
     Q->singam = sin(gamma0);