/** Compute the parameters need to create each cells */
private void initParameters() {
this.minX = envelope.getMinX();
this.minY = envelope.getMinY();
double cellWidth = envelope.getWidth();
double cellHeight = envelope.getHeight();
this.maxI = (int) Math.ceil(cellWidth / deltaX);
this.maxJ = (int) Math.ceil(cellHeight / deltaY);
}