LTRM Statistics
Estimating means and temporal trends using LTRM data: details with examples
Datasets
The code supplied in these pages use the following datasets as examples from the LTRM databases. Datasets with filenames that end in "wt" were generated using code supplied under Estimating sampling weights.
- The fisheries datasets in SAS format (BLGLP8 and BLGLP8wt) and comma separated text format(BLGLP8.csv and BLGLP8wt.csv) contain bluegill counts from day electrofishing for 1993-2004. Count data may also be obtained from the LTRM's fisheries database browser. However, data downloaded from that browser exclude records from sites at which species of interest were not observed. Hence, users interested in the analysis of LTRM fish count or detection data will typically need to add these "zero catch" records to their downloaded datasets.
- The macroinvertebrate datasets in SAS format (INVERT and INVERTwt) and comma separated text format (inverts.csv and invertswt.csv) include all data collected by the LTRM macroinvertebrate component from 1993 through 2004, the year of its termination.
- The vegetation datasets in SAS format (VAAM3FS3 and VAAM3FS3wt) and comma separated text format (VAAM3FS3.csv and VAAM3FS3wt.csv) contain data for wild celery collected from Navigation Pools 12 and 13 for 1998-2008. This dataset includes sites at which wild celery was not detected (the analogue of the zero catch sites mentioned for fish above). Postscript: The vegetation stratified random sampling database browser now provides records for sites at which a species was not detected provided users request data for a single rather than all species; see instructions at that site.
- The water quality datasets in SAS format (WQall and WQallwt) and comma separated text format (WQall.csv and WQallwt.csv) contain limnological data for a selected set of parameters collected by the LTRM water quality component from all Navigation Pools, and from all years through 2008. The data differ slightly from those that may be downloaded from the database browser in that data considered questionable by the water quality component specialist were deleted. The revised dataset also omits a number of lesser-used constituents (e.g., metals—which are no longer sampled, and some site physical characteristics), and adds columns for sampling year and episode.
Contact: Questions or comments may be directed
to Brian Gray, LTRM statistician, Upper Midwest Environmental Sciences
Center, La Crosse, Wisconsin, at brgray@usgs.gov.
Page Last Modified:
January 7, 2016