KB10243 - During my evaluation I discovered that the TatukGIS DK is much, much faster in reading shape files (less than 1 second for a 7.5 MB file with 11,000 polygons) than MapObjects, yet it is a little slower with labeling features compared to MapObjects. Why would the DK read shape files so fast, but not exceed MapObjects in labeling speed?

Yes, the DK is slightly slower than MapObjects with the label features, but please take into consideration that the DK is doing much more than MapObjects during the process. MapObjects simply draws the labels after generating each layer, and does not guarantee that labels in one layer are not hidden by features in another layer. The DK draws the layers two times. The first time a “fast draw” is generated, without labels and polygon fills. Then, after the “fast” draw of all layers has been performed, milliseconds later each layer is generated a second time with a precision draw. The labels are generated in the last step of the precision drawing process to ensure that labels never overlap, are never are hidden by a feature in a different layer, and are optimally positioned relative to the described vector in rotated label situations (such as the names of streets and rivers). We believe that the improved label presentation is worth the small reduction in speed.

The two-step drawing process employed in the DK also offers advantages during the dragging process, or when a map moves in the viewer in situations such as GPS tracking of a rapidly moving vehicle. Under the default Incremental Paint setting, the DK performs only the first (fast) draw while the map is moving, and performs the second (precision) draw a few milliseconds after any pause in the movement of the map. The result is a fast, incremental map presentation during the process of the map movement. (Some other GIS products present no incremental map information during the dragging process, i.e., the extra map territory is presented only as additional white margin space until the dragging movement stops.)

The incremental paint (two step drawing) procedure can also be turned off in the DK, resulting in the presentation of incremental map territory during the map dragging procedure as extra white margins. Then the full map presentation is performed only when the map stops moving. Since information is not incrementally presented during the map move procedure, this makes the process even faster. To turn the incremental paint off for any given layer, set

Layer.IncrementalPaint = False

To turn the incremental (two step) drawing process off in the overall viewer, set

Viewer.IntermentalPaint = False

Alternatively, Incremental Paint for any layer can be turned on/off witin the visual layer properties control. For more information on the Incremental Paint feature, refer to: KB10540.