Saturday, November 8, 2014

A Lesson in Geographical Coordinates & Insect Labels

Recently I've been creating labels for all the butterfly specimens I collected over the summer, and have also started replacing older labels with the new format I decided on after researching the proper labeling system for scientific/museum collections.  I discovered that there isn't very much information available online that describes a standard form for creating insect labels, and what is available often contradicts other sites.
In the past, I've labeled my specimens rather inconsistently, the labels changing over the years as I've experimented with what works best for me and learned more about the proper format.  Some sites say that a specimen must have two labels, and other sites say you only need a second one if you want, and some say the two labels must be the same size, while others say the second one can be smaller.  Adding to the confusion, some sources instruct you to label the information starting with the date, then the specific location (such as geographic coordinates), then give the county, state, and country, while others, including most museums that I see, start with the country, state, and county, then give the coordinates and date.  To further complicate matters, there are many ways to cite geographic coordinates. Should you use latitude/longitude? If so, in which format: decimal degrees, degrees decimal minutes or degrees minutes seconds? Or should you use PLSS (township/range/section) if you only collect in the USA?  I explained some of these issues in a past blog post about mapping butterfly records. The most universal method is to use lat/long coordinates as they are easily calculated for any location in the world, rather than other coordinate systems that use different projections depending on the country or region.  I will discuss the formats of lat/long coordinates below, after my instructions on creating labels.

After comparing several websites and studying how my peers and many museums label their specimens, I've come up with a "standard" format that I plan to use for all my specimens.
Font, label size, and printing
Font size - 4 to 6 pt, usually 4, which is what I now use.
Primary label - usually between 3/4" and 1" long by 1/4" to 1/2" wide, and contains all the location data and the date collected. Can also include other information as needed.
Secondary label - usually the same size or smaller than the primary label, and contains any extra information not on the primary label.  I usually keep this extra information (such as weather, time of day, butterfly behavior, flowers it was on, etc.) in a database rather than making extra labels.
Paper - use an acid-free light card stock (BioQuip sells this).
Ink - print labels with a laser printer, not inkjet, as printer ink will bleed or fade over time.  If hand-writing the labels, use an ink that will resist fading and bleeding, such as these from BioQuip.

Label Format
Location data - the primary label should start with the Country and/or State/Province, and the County/District (for example: WA: Cowlitz Co. or CANADA: BC: Vancouver Island). Specific location information should be included on additional rows, as described below.
Name & Determination - one label should have the species name and who determined it (made the identification).  I put this on my secondary label.

Creating labels in Microsoft Excel
I have found that the easiest way to create labels is with Excel.  Most of my labels are approximately 5/16" by 15/16", although some are slightly over 1" if the location information is longer.  In Excel, this means that most of my labels are in columns with a width of 10.86 (81 pixels), and rows with a height of 6.00 (8 pixels), with an extra row between each label that is 1.50 (2 pixels) high for spacing (see image below).  Although it looks like the text is overflowing the cell size, if you view the spreadsheet in Print Preview mode or print a sample page, you can see that it actually fits and is not cut off. Also make sure that the text is not too close to the label in the next column, or it will be difficult to cut them out without cutting off some of the text.
Depending on the location information I wish to include, my labels are either 4 or 5 rows.  Using labels of this size and 1/2" margins on the paper, you can fit 8 labels across and either 25 (5-row labels), 29 (4-row labels) or 38 (3-row labels) down to fill a standard 8.5x11" sheet of paper.
Once you print the labels, trim off the excess paper around the edge. I always save these blank strips and cut them into pieces to use for hand-written labels, waste not want not!  After the edges are trimmed, use a paper cutter to cut the labels into strips either by column or row, then use scissors to cut each label from the strip.

Row 1 contains the state, county, and date collected. I also print labels without dates for locations that I frequently collect in, so that I can write in the date by hand later, and not have to print and cut out labels every time I collect butterflies.  When typing the date, I simply add several spaces after the county name to make the date approximately even with the right side of the label, adjusting the number of spaces depending on the county name length, and checking it on the Print Preview screen to make sure the date isn't too far to the right.
Row 2 (and 3 if using a 5-row label) contains the more detailed location information, such as the national forest, road intersection, creek or lake name, etc.
Row 3 (or 4 if using a 5-row label) contains the geographic coordinates (latitude/longitude in decimal degrees; this will be explained in more detail below) and the elevation in feet. I've found that all of this fits at the size described above, when I use this format: N00.00000 W000.00000 elev 0000'. If the elevation is 10,000 ft or higher (i.e. over 4 digits), then you can remove the space between "elev" and the number to make it fit.  This information is very useful, but is not necessary if the other information describes a very specific location such as the address of a residence.
Row 4 (or 5 if using a 5-row label) contains the name of the person who collected the specimen, and is written as "coll. Name".  Some people put this on a separate label, but I have found this too tedious as it is extra work to cut them all out, and they are so tiny they are easy to lose and hard to handle.
Secondary label - species name and person who identified it
As mentioned above, I have started printing a separate label that only has the species name and the person who determined it.  These are simple, 2-row labels in the same font and row size as the primary labels, but the column width can be reduced to fit the length of the names as needed.  The species name is typed in italics on the first row, and the person's name is typed on the second row with the "det." prefix ("determined by") like this:
Papilio eurymedon
det. Caitlin C. LaBar
Example of butterfly labels in Excel, using Arial 4pt font. Note the narrow row separating each row of labels.

Latitude/Longitude formats
There are two parts to the format of lat/long coordinates. First is the identification of North/South and East/West.  These directions can be indicated either by the letter abbreviations (N, S, E, W) or by a positive number for North and East (40 degrees = North, 120 degrees = East) and a negative number for South and West (-40 degrees = South, -120 degrees = West).  The second part of the format is how the numbers are written: degrees minutes seconds, degrees decimal minutes, or decimal degrees.
There are 60 seconds in 1 minute, and 60 minutes in 1 degree. I prefer to use decimal degrees, partly because it is the simplest format, and partly because it takes up less room on my labels!  There is a setting in most GPS units that allows you to choose which of these three formats to use, and it will automatically change all of your recorded data to the new format.  If you have saved coordinates in another program or written them in a notebook in different formats, here is how to convert them:
From decimal degrees to degrees minutes seconds:
N 42.32482 --> 0.32482*60 = 19.4892 (42 deg 19.4892 minutes) --> 0.4892*60 = 29.352 --> 42 deg 19' 29.352" North
From degrees minutes seconds to decimal degrees:
42 deg 19' 29.352" North --> 29.352/60 = 0.4892 --> +19 --> 19.4892/60 = 0.32482 --> +42 = 42.32482 degrees North

The number of decimal places you should keep depends on which format you are using. In general, it is unnecessary to keep more than one decimal place for seconds in the degrees minutes seconds format. A difference of 0.1 seconds roughly translates to 3 feet of latitude or 7 feet of longitude (at mid-latitudes), which is often less than the accuracy of hand-held GPS units (usually have 10-20 feet accuracy).  Four decimal places in the decimal degrees format (42.3248) is roughly equivalent to having no decimal places in the degrees minutes seconds format (42 deg 19' 29"), and for each decimal place that is used in the seconds, another should be added to the decimal degrees format (42 deg 19' 29.4" = 42.32483 degrees).
Some other numbers to think about are (if I've done my math correctly, so don't quote me on this and correct me if need be!)...
1 minute of latitude is roughly equal to 1 mile
1 minute of longitude is roughly equal to 1 mile at mid-latitudes and 0.5 mile at high latitudes

Considering GPS accuracy and the fact that butterflies fly, I am quite happy with four decimal places when using decimal degrees, or no decimal places when using degrees minutes seconds, but I have decided to use 5 decimal places just to give myself a little extra wiggle-room if I ever want to round off the number or convert it to another format.

Hopefully you will find all these instructions useful and not too long and confusing!  There is no single "correct" format for insect labels, which is why there are so many versions, but it is important to be consistent in whatever format you choose. I welcome any comments on these or other solutions anyone has found helpful regarding insect labeling and coordinates.