To achieve global coverage without a North Pole grid singularity the OCCAM model uses two linked grids. The second grid is rotated, relative to the first, such that its "poles" lie on the geographical equator with its "equator" lying along the geographical meridian at 38° W.

This page provides a selection of utilities and maps to help orientate the user in model space. Three utilities are provided:

1. To convert geographical longitudes and latitudes to model longitudes and latitudes ( includes maps showing the relationship between model and real coordinates).
2. To convert model longitudes and latitudes to geographical longitudes and latitudes.
3. To convert model array indices into geographical and model longitudes and latitudes.

In each case, enter values in the top row of text boxes and click outside the text areas to update the output values. Output values are indicated by labels in italics. A diagram showing the relationship between the model and geographical domains may be displayed by clicking on the "show map" button in the first table. This diagram may be used to obtain a rough indication of the model longitude and latitude bounds of the region of interest. For example the entire ocean north of 60° N may be requested by using the model longitude and latitude bounds of 150° E to 199.5° E and -30° N to 30° N. The utilities below may be used to fine tune your region.