How to Make a Good Insect Specimen label … … and why
Digital Specimen Data • Wave of the future • Specimen labels = data sink (relatively primitive to get that data, borrow specimens, visit collections, etc. ) • Specimen labels transformed to digital format = data that can be used by the global community for many uses, some we have yet to envision
Geographical Concepts • 3 main concepts – Projection – Datum – Coordinate system
What projections do Rectangular projection Tissot’s Indicatrix of distortion
Geographical Concepts: Datum
Geographical Concepts: Datums Common Datums NAD 27 (North American Datum): system derived from landbased surveys, using Clarke 1886 ellipsoid NAD 83: satellite-based system using the Earth’s center as a reference point; eventually adopted as GRS 80 (Geodetic Ref. System 1980) WGS 84 (World Geodetic System 1984): mathematically refined GRS 80 used by the US military and default for GPS For most uses, NAD 83, GRS 80, WGS 84 are equivalent
Coordinate Systems • Degrees, minutes, seconds 39° 25’ 06”N, 92° 26’ 18”W • • Degrees, decimal minutes 39° 25. 1016’N, 92° 26. 2942’W Decimal degrees *** use this!! 39. 41837°, -92. 43824° N = +, S = -, E = +, W = -
What is a Georeference? Placing a spot on a map What is an acceptable georeference? Point: A numerical description of a place that can be mapped, and… Extent: that describes the spatial extent of a locality (or collecting event), and … Uncertainty: its associated uncertainties.
Insect Label: low vs. high quality 1 mi. E Moberly Randolph Co. , Mo. July 4 -5, 1972 Coll. E. G. Riley Old style – w/o georeference single label USA: MO: Randolph Co. 1 mi. E Moberly, Hwy. 24 39. 44929°N, 92. 40219°W (WGS 84), +/- 200 m VII-4 -5 -1972, E. G. Riley UV light, secondary growth oak-hickory forest Modern style – includes georeference Often need a double decker (= two labels/spec. ) Two labels vs. single label: Pro: keeps footprint of label small (4 or 5 lines) Con: twice the work cutting and placing
Common Georeferencing Practices: or, … what will happen to locality data from your old-style labels • Geolocate • Used for locating points and giving uncertainties, editing those points and uncertainties, finding new points from known points • Google Earth / Google Maps / GPS / paper maps, etc. • Used for locating points • Georeference calculator • Used for calculating uncertainties from known points via recommended “best practices” for particular locality types (named place, offset-heading, etc. ) Demonstrate with examples: Point –radius method
Out-Put from Geolocate Search
Geolocate results for … Moberly, MO * Note: Uncertainty resized to polygon 1 mi. E Moberly, MO
Output from Georef calculator for point at “ 1 mi. E of Moberly on Hwy. 24: Randolph Co. , Missouri” • • 39. 449941 lat -92. 406406 lon 7225 (WGS 84) World Geodetic System 1984 datum decimal degrees 3. 98237 4. 489 mi. = maximum uncertainty radius (= ½ of linear extent) ** Note that collecting event assumed to have taken place within a ca. 9 -mile wide circle • 1 mi • 0. 00001 degrees
Geolocate vs. Good Label 1 mi. E Moberly, Hwy. 24, MO USA: MO: Randolph Co. 1 mi. E Moberly, Hwy. 24 39. 44929°N, 92. 40219°W (WGS 84), +/- 200 m
Google Earth view
Suggested Protocol for Preparing Good Labels • Take GPS reading in field (especially if an obscure locality with poor landmarks) • Run GPS coordinates in Google Earth / Google Maps to relocate point at middle of extent of the collecting event (CE). • Calculate maximum uncertainty radius of CE (use ruler in Google Earth, etc. ) • Record coordinate source datum (GWS 84)
Suggested Protocol for Preparing Good Labels, con’t. • Review how to use a GPS (set datum, record GPS model etc, + GPS error with each waypoint) • Review how to take distance measurements using Google. Earth and Google. Maps • Create master copy of CE label (MS Word). • Cut coordinates from typed labels and paste into Google Earth for verification: must double check • Review how to format labels (font size, line spacing, etc. ) for printing in MS Word. • Review need for quality paper & printer
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