On the characteristic and diameter of planar integral point sets

A point set $M$ in Euclidean plane is called an integral point set in semi-general position if all the distances between the elements of $M$ are integers, and $M$ does not contain collinear triples. We improve the lower bound for diameter of such sets in the particular case when the characteristic of the set is of the form $4k+1$ or $4k+2$. To achieve that, we combine hyperbolae-based and grid-based toolsets.