A Virtual Museum on the State's Fish Biodiversity

Georeferencing and Geographic Units

Serious users should be aware of some potential issues that might arise due to the way localities were georeferenced.

Most of our records have been georeferenced (latitude/longitude determined) using accepted manual methods. Some could not, mostly due to internal conflicts in verbatim locality descriptions or vague locality descriptions. Others are localities outside our geographic scope. Georeferenced points have been checked by mapping and examining plotted species distributions against known distributions and we believe are highly reliable. Most outliers detected using this method are errors in specimen identification. However, some errors are not easily detected using our (or any reasonable) methodology. We encourage users, especially original collectors of our data, to help us identify errors in georeferencing by examining their own records. Records that we had trouble georeferencing are provided here and we ask that our users help us georeference these locations.

The content of many geographic categorical data fields (e.g. county, natural area, river basin, hydrologic units, etc.) was generated in a geographic information system following completion of georeferencing and only georeferenced records were assigned such categorical data. Queries using geographic fields will result in record sets including records with coordinates falling within the area of those categorical variables, regardless of our georeference error determination. For example, a location with coordinates in county A and an error that extends into county B will only be pulled when county A is designated in the query. Even though the overlapping georeferenced error estimate means that this record could likely occur in county B, it cannot be found by querying for county B. Future versions of the website will allow such “smart” queries, but at this time it is highly recommended that, when querying on geographic parameters, users include neighboring categories in addition to those of interest. This is especially important for queries of counties which have stream borders.

Fish obviously are limited to water, but not all coordinates in our database fall on water features. Users should remember that some locality descriptions are vague and do not allow precise placement of points.