# contourps documentation

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

The contourps works just like Matlab's contour or contourm functions, but plots georeferenced data in Antarctic polar stereographic coordinates (true latitude 71°S). For example,

`contourps(lat,lon,Z)`

is equivalent to

```[x,y] = ll2ps(lat,lon);
contour(x,y,Z)```

## Syntax

```contourps(lat,lon,Z)
contourps(lat,lon,Z,n)
contourps(lat,lon,Z,v)
contourps(...,LineSpec)
contourps(...,'km')
contourps(...,'meridian',meridian)
[C,h] = contourps(...)```

## Description

contourps(lat,lon,Z) draws contours of Z at gridded locations lat, lon.

contourps(lat,lon,Z,n) specifies a number of contour levels n if n is a scalar.

contourps(lat,lon,Z,v) draws a contour plot of matrix Z with contour lines at the data values specified in the monotonically increasing vector v. The number of contour levels is equal to length(v). To draw a single contour of level i, use v = [i i];

contourps(...,LineSpec) draws the contours using the line type and color specified by LineSpec. contourps ignores marker symbols.

contourps(...,'km') plots in polar stereographic kilometers instead of the default meters.

contourps(...,'meridian',meridian) specifies a meridian longitude in the polar stereographic coordinate conversion. Default meridian is 0.

[C,h] = contourps(...) returns contour matrix C and handle h of the contour object created.

## Example 1: Simple case

Contour some surface elevation data from bedmap2:

```[lat,lon,sfz] = bedmap2_data('sfz','res','5 km');

contourps(lat,lon,sfz)
``` ## Example 2: Polar stereographic kilometers

Using data from Example 1, plot in polar stereographic kilometers. For variety, use the cmocean (Thyng et al., 2016) haline colormap:

```figure
[C,h] = contourps(lat,lon,sfz,'km');

xlabel 'eastings (km)'
ylabel 'northings (km)'

cmocean 'haline'
clabel(C,h,'LabelSpacing',300,'fontsize',8)
``` ## Example 3: Specify levels

Specify every 200 meters surface elevation from sea level to 5 km:

```figure
contourps(lat,lon,sfz,0:200:5000,'km')
cb = colorbar;
ylabel(cb,'surface elevation (m)')
``` ## 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 University of Texas Institute for Geophysics (UTIG), July 2015, for inclusion in the Antarctic Mapping Tools package.