private void loadDataFromFESVoOnly(int[] dataDimension, int xLRef, int yLRef, int lod, int firstSlice, int lastSlice) {
        // [TEST] get starting time:
        long startTime = System.currentTimeMillis();
                
        // for every (s,t) in the texture buffer, 
        // load data from FESVo:
        for (int t = firstSlice; t < lastSlice; t++)
        {
            // calculate yL (local point on required LOD relative to the ref. point)
            int yL = t + yLRef;
            
            for (int s = 0; s < dataDimension[0]; s++)
            {
                // calculate xL (local point on required LOD relative to the ref. point)
                int xL = s + xLRef;
                
                // a loop through all sources to consider multi-features:
                for (int id : this.requiredIDs){
                
                    // create required point tag:
                    PointTag tag = new PointTag(xL, yL, id);

                    // check if FESVo has a data in this point:
                    GeospatialData data = FESVo.get(tag, lod);

                    // if data is found, load it to buffer:
                    if (data != null){
                        if (this.loadingFeatures){
                            if (this.loadAtLowerResolution)
                                this.uploadTextureBufferAtLowerResolution(s, t, lod, (Feature)data, id);
                            else
                                this.uploadTextureBuffer(s, t, (Feature)data, id);
                        }
                        // if loading a trace:
                        else{
                            if (this.loadAtLowerResolution)
                                this.uploadTextureBufferAtLowerResolution(s, t, lod, (Trace)data);
                            else
                                this.uploadTextureBuffer(s, t, (Trace)data);
                        }
                        

                        this.FESVoPointsCount++;
                    }//if

                    // if data not available in FESVo, do nothing
                
                }// go to next required ID
                
                
                
            }// go to next s
        }//completed all (s,t) of texture
        
        // get end time:
        long endTime = System.currentTimeMillis();

        // print result:
        System.out.println("\tLoaded " + this.FESVoPointsCount + " points from FESVo in " + (endTime - startTime) + "ms,");
        
        // clear counts:
        this.FESVoPointsCount = 0;
        this.dbVisitCount = 0;
        this.emptyUnitsCount = 0;
                
        // reset loadAtLowerResolution to false
        loadAtLowerResolution = false;
    }//loadData