About Combining Coordinate Values (Coordinate Filters)

# About Combining Coordinate Values (Coordinate Filters)

You can use coordinate filters to extract one coordinate value at a time from locations
on existing objects.

Coordinate filters specify a new coordinate location by using the X value from one location, the Y value of a second location, and, for 3D coordinates, the Z value of a third location. When used with object snaps, coordinate filters extract
coordinate values from an existing object.

Coordinate filters are commonly used to locate the center of a rectangle and to locate
the projection of a 3D point on the XY plane of the UCS.

To specify a filter at the Command prompt, enter a period and one or more of the letters
X, Y, and Z. The next entry is limited to a specific coordinate value.

## Example: Use of Coordinate Filters in 2D

In the following illustration, the hole in the holding plate was centered in the rectangle
by extracting the X,Y coordinates from the midpoints of the plate’s horizontal and vertical line segments.

Here is the Command prompt sequence:

Command: circle

Specify center point for circle or [3P/2P/Ttr (tangent tangent radius)]: .x

of: mid

of: Select the horizontal line on the lower edge of the holding plate

of: (need YZ): mid

of: Select the vertical line on the left side of the holding plate

Coordinate filters work only when the program prompts you for a point. If you try
to use a coordinate filter at the Command prompt, you see an error message.

## Example: Use of Coordinate Filters in 3D

This example shows how to use coordinate filters to create a point object at the center
(centroid) of a 3D object. Hidden lines have been removed for clarity. The X value of the new point is extracted from the first location specified, the Y value from the second location, and the Z value from the third. The three values are combined to form the coordinate values
of the new point.

Command: point

Point: .x

of mid

of select object (1)

(need YZ): .y

of mid

of select object (2)

(need Z): mid

of select object (3)

u can use coordinate filters to extract one coordinate value at a time from locations on existing objects. Coordinate filters specify a new coordinate location by …coordinate filters to extract one coordinate value at a time from locations on existing objects. Coordinate filters specify a new coordinate location by …Coordinate filters are useful for 2D construction, especially when combined with … With ESnaps, you can obtain separate X, Y, and Z values from significant …FILTERS. … 7.10.1 SAOimage Region Files; 7.10.2 Converting Coordinates In Region Files ….. Time filter files are combined in the following way: …. With the PSPC and GIS keyword values in hand, I use the formulae above to convert the X , …combine ACIS or HRC imaging data from multiple observations, e.g. to search for … Each event list contains all the World Coordinate System (WCS) information … unix% ds9 -cmap b merged1/merged_evt.fits -bin filter 'energy=500:7000' …. acis_process_events (CIAO): WARNING: The values of ENERGY and PI may be  …

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