There are two Excel spreadsheets in this folder. They are identical except for the format of input latitudes
and longitudes. "Map Projection Functions Decimal Degrees Input.xlsx" accepts input latitudes and longitudes
in decimal degrees. "Map Projection Functions DegMinSec Input.xlsx" accepts input latitudes and longitudes in
degrees, minutes, and seconds. Both spreadsheets require map projection parameters with angular units to be
in decimal degrees. Common map projection parameters can be copied and pasted from the fourth page of
each spreadsheet.
The spreadsheets perform direct and inverse transformations between geodetic coordinates (latitudes and
longitudes) and map projection coordinates (northings and eastings). They also compute convergence (mapping
angle) and scale factor at each computed point. In addition, they will compute linear distortion if an ellipsoid
height is provided.
A direct transformation converts a latitude/longitude pair into a northing/easting pair. An inverse transformation
converts a northing/easting pair into a latitude/longitude pair.
All distance values are and must be in meters. All longitude values are and must be positive east (0 - 360 degrees).
The page named "Parameters" contains the parameters for commonly used map projections in Wisconsin
(i.e. WISCRS, SPCS 83, and WTM 83). These parameters appear in the order that is required for the
computation pages, so they can be copied and pasted as needed. Users can also provide their own parameters by
keyboard entry in the appropriate cells on computation pages.
There are three computation pages in each of the two spreadsheets. On each of these pages, projection parameter
labels appear in rows 3 and 4. The parameters must be placed (copied and pasted, if appropriate) in row 5,
directly below their labels.
Each computation page has input and output cells for direct transformation in columns A-H. Input and output cells
for inverse transformation are in columns I-N. Rows 13 and higher contain computed projection constants and
intermediate variables for the transformations.
There are named computation pages for transverse Mercator, Lambert conformal conic (two standard parallels), and Lambert
conformal conic (central parallel and its scale factor) projections.
These spreadsheets perform computations for individual points.