`psgrid` documentation

`psgrid` is part of Antarctic Mapping Tools for Matlab (Greene et al., 2017). Click here for a complete list of functions in AMT.

This function creates a grid of specified spatial resolution in polar stereographic coordinates.

## Contents

## Syntax

[lat,lon] = psgrid(CenterLat,CenterLon,width_km,resolution_km) [lat,lon] = psgrid(CenterX,CenterY,width_km,resolution_km) [lat,lon] = psgrid(CenterName,width_km,resolution_km) [x,y] = psgrid(...,'xy')

## Description

`[lat,lon] = psgrid(CenterLat,CenterLon,width_km,resolution_km)` returns a grid of `width_km` width in kilometers, `resolution_km` resolution in kilometers, centered on the location given by `CenterLat`, `CenterLon`. If `width_km` is a two-element vector, the first element is interpreted as width and the second element is height. If `resolution_km` is a two element vector, the first element is interpreted as horizontal resolution and the second element is interpreted as vertical resolution.

`[lat,lon] = psgrid(CenterX,CenterY,width_km,resolution_km)` centers the grid on polar stereographic coordinate (CenterX,CenterY) in meters. Polar stereographic meters automatically detected if absolute values exceed normal values of geo coordinates.

`[lat,lon] = psgrid(CenterName,width_km,resolution_km)` centers a grid on any location or feature found in the SCAR database.

`[x,y] = psgrid(...,'xy')` returns a grid in polar stereographic meters (ps71).

## Example 1

Get an 600 km wide, 5 km resolution grid of geo coordinates centered at (75°S,107°W):

[lat,lon] = psgrid(-75,-107,600,5);

We can show the grid on a map as blue dots atop a Landsat Image Mosaic of Antarctica image using the `lima` function:

lima(-75,-107,800,'xy') plotps(lat,lon,'b.')

## Example 2

In a standard polar stereographic projection, Amery Ice Shelf is wider than it is tall. Let's create a 10 km grid over Amery and make it 900 km wide by 250 km tall. Also, we'll include the `'xy'` option to return polar stereographic cartesian coordinates rather than the default geo coordinates.

[X,Y] = psgrid('amery ice shelf',[900 250],10,'xy');

The grid can be shown as blue dots in cartesian coordinates like this:

figure bedmap2('patchshelves','xy') hold on bedmap2('patchgl','xy') plot(X,Y,'b.') axis(1000*[757 3093 -170 1673])

## Citing AMT

If this function or any other part of Antarctic Mapping Tools is useful for you, please cite the paper that describes AMT.

Greene, C. A., Gwyther, D. E., & Blankenship, D. D. Antarctic Mapping Tools for Matlab. *Computers & Geosciences*. 104 (2017) pp.151-157. doi:10.1016/j.cageo.2016.08.003.

## Author Info

This function was written by Chad Greene of the Uninversity of Texas Institute for Geophysics (UTIG), September 2015.