Project
Project [/C={long,lat }/M=method /P={p1,p2,...}] longitudeWave, latitudeWave
The Project operation calculates projections of XY data, which most often are longitude and latitude waves of geographic coordinates. The output waves are W_XProjection and W_YProjection. Longitude and Latitude are in degrees.
Parameters
longitudeWave is the name of the wave supplying the longitude or equivalent coordinates. latitudeWave is the name of the wave supplying the latitude or equivalent coordinates.
Flags
| /C = {long,lat } | Specifies longitude and latitude center of projection. By default, long=0 and lat=90. | ||||||||||||||||||||||
| /DSTX = xWave | Specify the output wave x component of the projection. If you do not specify this flag, the operation saves the data in the wave W_XProjection in the current data folder. | ||||||||||||||||||||||
| This flag was added in Igor Pro 10. | |||||||||||||||||||||||
| /DSTY = yWave | Specify the output wave y component of the projection. If you do not specify this flag, the operation saves the data in the wave W_YProjection in the current data folder. | ||||||||||||||||||||||
| This flag was added in Igor Pro 10. | |||||||||||||||||||||||
| /FREE | Creates all destination waves as free waves. This flag does not affect an output wave that is created by default without a user-specified destination. | ||||||||||||||||||||||
| /FREE is allowed only in functions, and only if the destination waves are simple names or wave reference structure fields. | |||||||||||||||||||||||
| See Free Waves for more discussion. | |||||||||||||||||||||||
| The /FREE flag was added in Igor Pro 10.00. | |||||||||||||||||||||||
| /M = method | Indicates the type of projection. method can be one of the following: | ||||||||||||||||||||||
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| /P = {p1,p2,...} | One or more parameters required by a particular projection. See below for details regarding the individual projection requirements. | ||||||||||||||||||||||
Gnomonic
Here there is one extra parameter that defines the boundaries based on the angle. The specific expression for the limit is that cos(c) in Eq. (5-3) of Snyder is greater than the specified parameter:
/P={cos(c)}
The actual transformation uses Eqs. (22-4) and (22-5) with k' given by (22-3).
General Perspective
Here there is one extra parameter that defines the boundaries based on the angle. The specific expression for the limit is that cos(c) in Eq. (5-3) of Snyder is greater than the specified parameter.
The actual transformation uses Eqs. (22-4) and (22-5) with k' given by (22-3). Here we specify the height H is units of sphere radius. The tilt of the plane is specified by omega and gamma following the notation of Snyder page 175.
The parameters actually specified by the command are:
/P={H,omega,gamma,deltax,deltay }
H is the height (in radii) above the surface of the earth, gamma is the azimuth east of north of the Y axis, and omega is the tilt angle or the angle between the projection plane and the tangent plane. The x output will be limited to +/- deltax and the y output will be limited to the range +/- deltay.
Mercator
This projection requires the following parameters:
/P={minLong,maxLong,minLat,maxLat }
If /P is not specified, the default is {0,360,-90,90}
Note that this projection flips the sign of y when cos(longitude-long_0) changes sign. If you are plotting a continuous path in which consecutive points exhibit the sign change, you should add a NaN entry in the wave so that the path does not wrap.
Albers Equal Area Conic
This projection requires:
/P={minLong,maxLong,minLat,maxLat,Phi1,Phi2 }
Phi1 and Phi2 are the specification of the two standard parallels, the other four parameters determine the boundary of the map area for display.
References
Snyder, John P., Map Projections-A Working Manual, U.S.G.S. Professional Paper 1395, U.S. Government Printing Office, Washington D.C., 1987, reprinted 1989, 1994, 1997 with corrections.