OutdoorNebraska

20 In order to produce a map, we need the latitude and longitude for the collection locations. Many of the data sources required some work to generate these. In the case of my own collections and those of the Universities, the location of collection was often recorded directly with a handheld GPS unit. For the NGPC staff and Citizens, the location could be found on Google Earth and the latitude/longitude could be noted. A number of Museum collections were older records, some of which had meager locational information. If there was enough information to figure out the sample location, then a latitude/longitude pair was calculated. Some of these did not have adequate information so could not be used. The information available in the "Published reports" varied. Two publications did provide latitudes and longitudes for their collection locations. 5, 10 One publication provided detailed descriptions of the collection sites which were sufficient to determine their latitudes and longitudes. 9 Three publications provided maps that were used to determine collection locations. 4, 39, 41 The several reports by Ellet Hoke included both dot maps and tables listing waterbodies sampled as well as species sampled at each location. 18, 19, 20, 21, 22, 24, 25 The dots on the map were numbered and these corresponded with numbered sites in the tables. These maps and tables were used in conjunction with a computer mapping software package (DeLorme 3-D Topoquads, 1999) and 1:24,000 USGS topographic maps to guesstimate his probable collection sites for which latitudes and longitudes were determined. [I should note that while Mr. Hoke has deposited many mussel shells in the Ohio University museum, these were ignored because of the possibility of double counting them.] In the field and, subsequently, in the database, shell collections were recorded as "Live", "Fresh dead", "Dead", "Weathered dead" and "Chalky". These data were sorted by species and condition. Then the first two and last two categories were combined into just three categories (Live, Dead, Relict) for mapping. The latitude and longitude data for each species and category were used to create text files. The open-source GIS software QGIS (Version 2.6.1) then used these text files to generate the maps presented here.

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