Snapping to Region Centriod (Posted Pre 2007)

[Anonymous 0]

Is there a MapInfo tool for snapping to the centroid of a region? Eg. Creating SX boundary conditions for use with ISIS-TUFLOW. Alternatively advice would be welcome on snapping the end of a cn line to an SX region without having to play around with MIF files in UltraEdit. (Sadly the ZC points in the files created by TUFLOW are not always at the centroids of the grid regions created in the check files)

[Bill Syme 0]

Regarding the snapping, you can snap to region centroids by turning Show Centroids on using the Display Options for that layer in the Layer Control, and using the snap tool in the usual way. If the region's layer is editable you can also move the region's centroid by selecting the region, pushing the Reshape icon in (the centroid now appears as a yellow square) and dragging and dropping the centroid to where you want it.

However, I'm intrigued as to why you are using regions for SX objects. They are normally (always) a point or a polyline, the polyline being used when more than one cell is needed to be connected to (this maybe important for stability where the 1D channel/culvert is relatively large compared to the 2D cells so that large volumes of water being interchanged between 1D and 2D are being spread over several cells rather than one). If the ISIS or ESTRY node is not snapped to the point or line, then a single CN object is needed to join them. If using a region for SX objects, it will only select one 2D cell, that being the one that the region's centroid falls within (it won't select all cells within the region), and like you've observed, the CN object or ISIS node needs to be snapped to the region's centroid. Use the 1d_to_2d_check.mif file to crosscheck which cells have been selected as SX and HX links.