How do I project my data?

The following projections are available within Gsharp:

UTM	Transverse Mercator	Mercator
Lambert Conformal	Azimuthal Stereographic	Gnomonic

Other projections can be implemented in GSL

There are many functions for controlling the built-in projections and they are described in the GSL function reference section. The main three routines are:

• proj_type() - to set the projection
• proj_origin() - to set the origin of the projection
• proj_transfrom() - projects (latitude,longitude) data.

As you can see from the example below the only other step you must consider is setting the X Ratio and the Y Ratio of the viewport so that 1 unit of X equals 1 unit of Y. The simplest way to get this correct is to set xRatio equal to the range of the X axis and yRatio equal to the range of the Y axis.

Once you have set up the projection using proj_type and proj_origin, you must then call proj_transform everything that you want to add to your plot - the data, a worldmap, a grid.

#Example

import_worldmap("", "full", "CoastLong", "CoastLat", -90,-60,15,40);
BermudaLong = -65 // -81.6// -66.2// -65;
BermudaLat = 32.33//  30.5//  18.5//  32.33;

proj_type("utm");
proj_origin(12,55);

proj_transform(CoastLong, CoastLat, "CoastLongP", "CoastLatP");
proj_transform(BermudaLong, BermudaLat, "BermudaLongP", "BermudaLatP");

create Viewport page_1.viewport
   ( XuNxRatio = 3,
     XuNyRatio = 3
   );
create Domain page_1.viewport.domain;
page_1.viewport.domain.xaxis1.XuNaxle = false;
page_1.viewport.domain.yaxis1.XuNaxle = false;
create Graph page_1.viewport.domain.graph_1 
   ( XuNgraphType = "line",
     XuNxData = "CoastLongP",
     XuNyData = "CoastLatP"
   );
create Graph page_1.viewport.domain.graph_2
   ( XuNgraphType = "line",
     XuNxData = "BermudaLongP",
     XuNyData = "BermudaLatP"
   );