The process of placing historic maps on current maps ("georeferencing") is done by matching points on the historic map to corresponding points on a current basemap. In this case, the USGS topo map and the relief maps were used. It is not an exact process. One can see above how the historical documents fit well in some places, and badly in others. This is to say that the historic maps are best considered as showing features in their current day vicinity, not their exact location.
confederate road map c. 1864: This is a captured confederate map showing the route of the road between Natchitoches and Alexandria (only the portions within Natchitoches Parish are shown here). It was originally drawn in many segments on both sides of a single piece of paper. It has been scanned, edited, and georeferenced for display on this map. In the National Archives it is record number Z33-138 in the Civil Works Map File, and at the Cammie G. Henry Research Library it is map numbers 1470 and 1471.
historic plat maps: This layer comprises many historic township plat maps, all acquired through the Louisiana State Land Office Historical Documents database. These are not necessarily the oldest plats for each township, but the date of the map has been added in the top right/northeast corner of each township. Each plat has been cropped and edited to remove the background color, etc. These maps clearly illustrate the original French survey system, which appears as rays emanating from the curves of the Cane River. In the western portion of the parish, many original Spanish land grants can be seen as well.
natchitoches 1866: This is a plat map of the city of Natchitoches from 1866. It is map number 174 at the Cammie G. Henry Research Library.
confederate maps: These maps all come from the Civil Works Map File. They are purportedly captured confederate maps from the Civil War, however, little scholarship has been carried out on them.
aerial imagery: Tiles courtesy of MapQuest, portions courtesy of NASA/JPL-Caltech and U.S. Department of Agriculture Farm Service Agency
relief: This layer is a hillshade derivative of LiDAR data acquired through Atlas, the Louisiana statewide GIS. The data was produced for the Louisiana State LiDAR Project. The original tiles were combined and clipped in ArcMap and new tiles were generated in TileMill.
elevation + relief: This layer is a combination of hillshade and elevation data derived from LiDAR data acquired through Atlas, the Louisiana statewide GIS. The data was produced for the Louisiana State LiDAR Project. The original tiles were combined and clipped in ArcMap and new tiles were generated in TileMill.