Transforms which appear in the template list when a geometry field, of type geom, geommfd, or geomwkb, has been picked in the Transform pane.
Note: spatial overlays, previously done using transform templates are now done using the Join dialog.
Click on a template's link to jump to that template's topic.
Compute buffer zone geometry given the Distance and Unit of measure specified and save into the specified Result destination, using the geometry type of the destination or choosing geom, geommfd, or geomwkb when saving to a new field or new table. A positive Distance creates a buffer zone area surrounding points, lines and areas. A negative Distance writes NULL geometry for points and lines, and for areas creates a inner buffer zone area that is reduced from the original area boundary by the distance of the buffer. If the area is so small that the inner buffer zone is reduced to nothing a NULL geometry value is written.
The units of measure provided depend upon the unit of measure used in the geometry field. For radial coordinate systems (for example, using degrees for units of measure as in Latitude / Longitude) available units will be Arc Minute, Arc Second, Degree, and Radian. For linear coordinate systems (for example, PseudoMercator), the Unit box will be populated with the long list of linear units Manifold knows.


Compute the centroid of objects using:
See the Center and Centroids topic.


Clean the geometry of objects using available operations:


Clip objects in the source drawing using area objects in the Clip with drawing. The Keep inner part option regulates what is left after the clip. Checking the Keep inner part option leaves only those portions of objects in the target drawing that are inside of the Clip with areas. Unchecking the Keep inner part option leaves only those portions of objects that are outside of the Clip with areas. The transform allows operating only on the selection in the target drawing, and also allows clipping only with selected areas in the Clip with drawing. The Clip transform template is a different command than the interactive Clip editing command.
See the Clip (Transform) topic for details and illustrated examples.


Compose a geometry value from coordinate numbers and save to the specified Result destination:


Convert objects to their equivalent as area, line, or point objects. Converting areas to lines or to points will created branched lines (multilines) or branched points (multipoints). Converting lines to points will create branched points. Such branched points can be converted into lines or areas, and branched lines can be converted into areas, because branched points and branched lines contain within their coordinate ordering the sequence information required to construct a higher level object, such as lines or areas from branched points, and areas from branched lines.


Provides numerous operators to extract or to compute geometry characteristics and to save to the specified Result destination, using the data type required and providing rich options for each operation. Available operations include:


Compute the minimum enclosing area shape desired for objects and save into the specified Result destination using the specified geometry type. Options in the Enclose in box for enclosing shapes are:


Save the result of the given expression into the specified Result destination using the specified geometry type.


Create raster data in the specified Result destination and specified data type by interpolation using values in vector objects in a drawing. Parameter boxes will automatically appear as required by different interpolation options.
Typical interpolation parameters, depending on the operation:
Do not use a Resolution of 1 with a Unit of Degree when drawings are in a radial coordinate system, like Latitude / Longitude. That creates pixels which are 1 degree in size, many kilometers in size in most parts of the world. If drawings are in a linear coordinate system and the Unit chosen is Meter, a Resolution of 30 creates pixels that are 30 meters by 30 meters in size. To keep units straight, it is best to do interpolations using drawings that have been projected into linear coordinate systems, and not radial coordinate systems like Latitude / Longitude.
Interpreting various combinations of specified (positive value) or autocomputed (zero or negative value) for Radius and Neighbors:
Interpolation Model options:
Regression model options:
The SQL function used within interpolation transform templates operate on objects that have Z values within their geoms. The transform automatically takes Z values from the designated field and temporarily adds them as Z values within the geom for each object so the function used can operate. The starting data is not changed, so after running this transform objects will not end up with Z values in their geoms.
Kriging operations produce a report of the parameters used, including resolved values for autocomputed parameters, and save the report into the description property of the new image component.
In Kriging, geoms without Z values are ignored. All geoms are converted to coordinates. Duplicate XY coordinates are ignored: if duplicate XY coordinates have different Z values, the operation uses one of these values and ignores any other Z values. If there is too little data to set up the model, Kriging degrades to Gravity interpolation.
About regression Kriging: Imagine an undulating surface that lies on the slope of a large hill, where if the surface were not bumpy we would have a smooth plane inclined at the overall angle of the hill. Suppose now we have many points that lie on the surface with each point providing the X,Y, and Z value of the surface at that point. Some regions of the surface have relatively few points or are lacking points.
The general task of Kriging is to take the collection of many points and to recreate the surface, filling in through computation some plausible interpolation in regions where sample points are sparse or missing. Ordinary Kriging simply takes the X,Y,Z values of the points and applies Kriging computations to interpolate a surface.
Regression Kriging first attempts to ascertain the overall inclined plane and to remove that as a bias, to allow considering the undulating surface as if it were arranged horizontally and not tilted on the overall slope of a hill. A Kriging calculation is performed on the adjusted, "as if level," coordinates of the points, and then the resulting interpolated surface is titled back to the original overall incline. The choice of linear or quadratic regression is a choice of how the original "overall" tiltedplane setting is determined.
Regression Kriging can identify and set aside more complex biases than the case of an undulating surface within a simple, overall incline in a hill. This nonmathematical description provides an analogy, not an exact phrasing of the math involved, to help nonmathematicians understand how Regression Kriging can provide better results than ordinary Kriging.


Combine objects, optionally grouping by an attribute field, and save the combined result into the specified Result destination using the specified geometry type. Objects to be merged optionally can be grouped by a field given in the Group box. Options in the Merge into box are:
Notes:
The center operations when the mfd_id field is used for grouping are equivalent to the Center transform, since simply a centroid of the desired sort is created for each object.
Whenever a circle is mentioned in the above, that is a circular figure within the coordinate system of the drawing, or an approximation of a circle in radial coordinate systems like Latitude / Longitude. Use a linear coordinate system that preserves measurement of distance in the region of interest to generate "real" circles.
Creating branched point objects using the points option is generally a very bad idea, because the result is something that looks like independent point objects but which in fact is a single, branched object, a socalled "multipoint." Friends do not let friends create multipoints.


Perform an ESRIstyle topology overlay on a pair of drawings in a map using identity, intersect, union, or update. The result drawing includes fields from the source drawing (transferred using the original field names) as well as fields from the overlay drawing (transferred using original names as modified based on the specified pattern, by default Overlay {name}). Both drawings can be restricted to the selection. Options in the Operation box are:


Alter the shape of objects using the specified operation and parameters, and save into the specified Result destination using the specified geometry type. Z values are preserved and 2D curvilinear segments are preserved, but 3D curvilinear segments are replaced with 3D straight line segments. Options in the Operation box are:


Decompose objects into constituent elements as specified in the Split into box and parameter options, and save into the specified Result destination using the specified geometry type. Split into options are:


Simultaneously adjust coordinates that define points, lines and areas to accomplish several tasks at once, considering all of the objects in the drawing. Alters any clockwise rotation area boundary sequences to OGC style counter clockwise rotation boundaries. Frequently used to prepare drawings for use as a network or for similar purposes.
See the Normalizing Topology topic.


Computed bounded areas and save into the specified Result destination using the specified geometry type. Given line objects, creates areas in regions entirely enclosed by selfintersecting, intersecting or otherwise touching lines. Areas and points are ignored.
Saving the result into a new drawing / table called Bounded Areas creates five areas:


Perform a Delaunay triangulation on all points and multipoints, creating triangular areas or lines as specified in the Output type box, and save into the specified Result destination using the specified geometry type. Ignores areas and lines in the original geometry field.


Create areas or lines as specified in the Output type box that create a Voronoi diagram for the positions of points in the source geometry field. Areas and lines are ignored. A Voronoi diagram divides the drawing into regions around each point that are shaped so that the borders of the regions are equidistant from the two nearest points. The Margin setting allows choosing a Margin distance in X and Y directions in the specified unit of measure from the nearest points, to clips the extent of Voronoi cells to the resulting enclosing rectangle. The Unit setting allows choosing a unit of measure.

Virtual drawings  Operations on geometry can use any table with a geometry field. The geometry field does not have to be part of a spatial index, although having such an index will frequently help performance. A query function that operates on geometry can accept either a physical drawing component stored in a database, or a virtual drawing created on a geometry field (using the ComponentFieldDrawing function) of a table or of a query component. A virtual drawing supports all functions available for regular components: for example, it can report its coordinate system or the name of the underlying component. Both physical and virtual drawings can be limited to using only selected records with the result being accepted as a drawing by query functions.
Tolerance  Operations on drawings do not specify a tolerance value except for a few special cases where this value materially defines the operation, for example, normalize. The tolerance value passed to query functions that require a tolerance argument is set to 0, for automatic tolerance. In the future, this parameter likely will be removed from most functions altogether, so users need not consider it at all.
Pass through of unaffected geometry  Geometry transforms that only make sense for a particular geometry type keep geometry values of other types unchanged whenever this makes sense. For example, reversing lines will keep areas and points unchanged instead of turning them into NULLs.
Uneven X and Y scales are OK  Geometry transforms that operate on distances also automatically compensate for uneven X and Y scales. Previously, if a coordinate system of a geometry field had different scales by X and Y, creating a buffer would create a circle in the coordinate system of the drawing which would become an ellipse if the scales for X and Y were made the same. Same for other distance computations. Now the transforms make the X and Y scales even prior to computing the buffer and then force the computed buffer back to the scales used in the coordinate system. This makes the results of computations independent of the scales used in the coordinate system, which is much more reasonable.
Curvilinear segments  As a practical matter, most people doing GIS will use straight line segments for lines and areas. Few GIS systems do a good job of supporting curved segments, so there is much less data published using curved segments. Manifold's ability to work with curved segments allows us to use that data within Manifold in a limited way, at least for display and interactive editing.
However, most processing tools in Manifold, such as Transform templates and various Geom SQL functions, do their work by first converting a curvilinear segment into a straight line segment between the same two start and finish coordinates. That will often lead to weird or otherwise unexpected results. To avoid such problems, first convert curvilinear segments into equivalent constellations of straight line segments at whatever resolution is desired, using the Clean transform template with the convert curves to lines operation option and the number of linear segments desired to approximate the curve in the Curve limit parameter. See the Curved Segments discussion in the Drawings topic.