Method for loading and displaying gridded data by determining the usefulness of a particular vertex

A non-transitory tangible computer readable medium containing a computer executable program for displaying gridded datasets, wherein said computer executable program, when read, will cause a computer to perform the steps of:

• creating at least one level tree node;
• IF more than one tree node is created, THEN
• linking neighboring said tree nodes;
• OTHERWISE
• measuring the defined quality of said at least one tree node;
• IF said defined quality is less than a predetermined goal, THEN
• refining a particular view, further comprising the steps of
• determining the usefulness of a particular vertex of gridded data;
• retrieving additional data so as to satisfy a view refinement criteria;
• and
• performing a redraw;
• OTHERWISE
• IF said defined quality exceeds a predetermined goal, THEN
• decimating a particular view;
• OTHERWISE
• generating triangle fans from said at least one tree node so as to facilitate their rendering as an input to a graphical display;
• wherein within said step of generating triangle fans, said computer executable program further causes said computer to perform the steps of:
• for each said at least one tree node, a first step of transforming the current vertex position of its originating center index node into a coordinate system of interest;
• a first step of adding said transformed current vertex position to an initially empty draw list;
• a first step of following said transformed current vertex's upward link to a first index node;
• a second step of transforming the current vertex position of said first index node into said coordinate system of interest;
• a second step of adding said transformed current vertex position of said first index node to the end of said draw list;
• determining whether said current vertex has a bottom link;
• IF said current vertex does NOT have a bottom link, THEN
• returning to said first step of following;
• OTHERWISE
• a second step of following said transformed current vertex's downward link to a second index node;
• a third step of adding said transformed current vertex position of said second index node to the end of said draw list;
• determining whether said current vertex has a right link OR said right link points to said vertex position of said originating center index node;
• IF said current vertex does NOT have a right link OR said right link points to said vertex position of said originating center index node, THEN
• returning to said second step of following;
• OTHERWISE
• a third step of following said transformed current vertex's rightward link to a third index node;
• a fourth step of adding said transformed current vertex position of said third index node to the end of said draw list;
• determining whether said current vertex has a top link OR said top link points to said vertex position of said originating center index node;
• IF said current vertex does NOT have a top link OR said top link points to said vertex position of said originating center index node, THEN
• returning to said third step of following;
• OTHERWISE
• a fourth step of following said transformed current vertex's upward link to a fourth index node;
• and
• a fifth step of adding said transformed current vertex position of said fourth index node to the end of said draw list;
• determining whether said current vertex has a left link OR said left link points to said vertex position of said originating center index node;
• IF said current vertex does NOT have a left link OR said left link points to said vertex position of said originating center index node, THEN
• returning to said fourth step of following;
• OTHERWISE
• a fifth step of following said transformed current vertex's leftward link to a fifth index node;
• a sixth step of adding said transformed current vertex position of said fifth index node to the end of said draw list;
• determining whether said current vertex has a bottom link;
• IF said current vertex does NOT have a bottom link, THEN
• returning to said fifth step of following;
• OTHERWISE
• outputting said triangle fan to the input of a graphical display process.

Apparatus for displaying gridded datasets, comprising:

• means for creating at least one level tree node;
• IF more than one tree node is created, THEN
• means for linking neighboring said tree nodes;
• OTHERWISE
• means for measuring the defined quality of said at least one tree node;
• IF said defined quality is less than a predetermined goal, THEN
• means for refining a particular view, further comprising means for
• determining the usefulness of a particular vertex of gridded data;
• retrieving additional data so as to satisfy a view refinement criteria;
• and
• means for performing a redraw;
• OTHERWISE
• IF said defined quality exceeds a predetermined goal, THEN
• means for decimating a particular view;
• OTHERWISE
• means for generating triangle fans from said at least one tree node so as to facilitate their rendering as an input to a graphical display;
• wherein said means for generating triangle fans further comprises means for:
• for each said at least one tree node, a first means for transforming the current vertex position of its originating center index node into a coordinate system of interest;
• a first means for adding said transformed current vertex position to an initially empty draw list;
• a first means for following said transformed current vertex's upward link to a first index node;
• a second means for transforming the current vertex position of said first index node into said coordinate system of interest;
• a second means for adding said transformed current vertex position of said first index node to the end of said draw list;
• means for determining whether said current vertex has a bottom link;
• IF said current vertex does NOT have a bottom link, THEN
• means for returning to said first step of following;
• OTHERWISE
• a second means for following said transformed current vertex's downward link to a second index node;
• a third means for adding said transformed current vertex position of said second index node to the end of said draw list;
• means for determining whether said current vertex has a right link OR said right link points to said vertex position of said originating center index node;
• IF said current vertex does NOT have a right link OR said right link points to said vertex position of said originating center index node, THEN
• means for returning to said second step of following;
• OTHERWISE
• a third means for following said transformed current vertex's rightward link to a third index node;
• a fourth means for adding said transformed current vertex position of said third index node to the end of said draw list;
• means for determining whether said current vertex has a top link OR said top link points to said vertex position of said originating center index node;
• IF said current vertex does NOT have a top link OR said top link points to said vertex position of said originating center index node, THEN
• means for returning to said third step of following;
• OTHERWISE
• a fourth means for following said transformed current vertex's upward link to a fourth index node;
• and
• a fifth means for adding said transformed current vertex position of said fourth index node to the end of said draw list;
• means for determining whether said current vertex has a left link OR said left link points to said vertex position of said originating center index node;
• IF said current vertex does NOT have a left link OR said left link points to said vertex position of said originating center index node, THEN
• means for returning to said fourth step of following;
• OTHERWISE
• a fifth means for following said transformed current vertex's leftward link to a fifth index node;
• a sixth means for adding said transformed current vertex position of said fifth index node to the end of said draw list;
• means for determining whether said current vertex has a bottom link;
• IF said current vertex does NOT have a bottom link, THEN
• means for returning to said fifth step of following;
• OTHERWISE
• means for outputting said triangle fan to the input of a graphical display process.