2018. Iowa Department of Natural Resources. Topographic Maps Each zip file contains a MrSid compressed image of the topographic quads of a certain Iowa county.
1984-86. Iowa Department of Natural Resources. Land Cover of Iowa in From 1984 to 2003 This zip file contains a 15-meter ESRI GRID of the Land Cover of Iowa.
2017. Iowa Department of Natural Resources. Karst and Sinkholes in Iowa This coverage contains a GRID representing areas within 1000 feet of known sinkholes and other areas that have carbonat...