Burton's version of Sleepy Hollow was quite different than the story version. Much of the storyline was altered, including an addition of the "evil stepmother" and her plan to wreak havoc on the entire town by summoning the Hessian soldier. I found Katrina to be the most changed because in the short story she did not seem to return Ichabod's affections. She was described to be a "plump" girl and she did not have much to do with the storyline. Ichabod seemed to be more interested in the Van Tassel's wealth and farm rather than Katrina in Irving's story. However, he still had a slight attraction to her.
In the movie, Ichabod and Katrina were very much in love. Katrina also used a little bit of witchcraft to help "protect" Ichabod or her loved ones when they were in trouble. The story did not describe her in length, while the movie focused mostly on her and Ichabod, essentially.