Is SharpMap free with no strings attached?
No (but almost) - There are some caveats:
Even though SharpMap is released under GNU Lesser General Public License, it doesn't make it completely free to use without any strings attached. SharpMap is free in the sence that anyone can download and use it for their applications, but the GNU LGPL
license restricts its use. If you modify, add or create a new project based on SharpMap, that too will be bounded by GNU LGPL.
The LGPL does not require you to release your modified version. You are free to make modifications and use them privately, without ever releasing them. This applies to organizations (including companies), too; an organization can make a modified version and
use it internally without ever releasing it outside the organization.
But if you release the modified version to the public in some way, the LGPL requires you to make the modified source code available to the program's users, under the LGPL.
In other words: The GNU LGPL will require that all the released improved versions be free software.