Rainsford line (e), International ellipsoid Rainsford line (d), International ellipsoid Rainsford line (c), International ellipsoid Rainsford line (b), International ellipsoid ![]() * on the ellipsoid with application of nested equations, Survey Review 22(176): (1975) Direct and inverse solutions of geodesics * Duplicate all 5 examples Vincenty used to compare his results with those of Here's a small subset:Ĭode: * Choose to run this script under the executable versionĬscript "geodist - Stata version `c(stata_version)' " adofile geodist With respect to the validity of the results produced by my programs, I'm always happy to provide all certification scripts that I use upon request. That's because ArcGIS works with projected coordinate systems. I'm no expert on ArcGIS, but as far as I can tell, ArcGIS has historically calculated Euclidean distances between features. The Haversine and Laws of Cosine equations (which are mathematically equivalent) are used if the earth is modeled as a sphere. By default, the shape of the earth is approximated using the WGS 1984 reference ellipsoid (what GPS devices and Google Earth/Map use) and distances are computed using Vincenty's inverse solution equations. ![]() Both are available from SSC.Īs explained in detail in the help file, geodist calculates the length of the shortest curve between two points along the surface of a mathematical model of the earth. * Example generated by -dataex-.I'm the author of geodist, which is a standalone version of the distance routines I wrote for geonear, a program that finds nearest neighbors using geodetic distances. This might be a simple problem and I can do it "outside" stata but still I am wondering how it can be solved with Stata.ĭataex LCpeakCh1P1dB LAFmaxCh1P1dB LAFminCh1P1dB LAeqCh1P1dB LCpeakCh1P2dB LCFmaxCh1P2dB if RECORD>17000Ĭopy starting from the next line. I post a small sample of my input data and output data. Basically using the -exp()- function with values around above 90 returns me missing values ! I wonder why this is and how it can be solved ? I have an issue with exponentiation of big numbers with Stata so i can make some calculations and then take the logarithm again.
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