Using the Warp processes

Legacy:

ArcGIS 10 is the last release of the stand-alone ArcGIS Image Server product. The image service definition (.ISDef) has been replaced by an improved geodatabase data model—the mosaic dataset—which can be published as an image service using the ArcGIS Server Image extension.

There are three types of Warp processes: Warp-Affine, Warp-Grid, and Warp-SRS. These processes can be applied only at the raster level.

Warp-Affine process

The Warp-Affine process enables you to perform an affine transformation, or affinity. This process is automatically included in the process chain when you add a georeferenced raster to your image service definition.

The affine type represents a linear transformation that preserves collinearity, parallelism, and ratios of distances. While an affine transformation preserves proportions of lines, it does not necessarily preserve angles or lengths.

In general, an affine transformation is a composition of rotations, translations, dilations, and shears. It has 6 degrees of freedom (parameters) A0, A1, A2, B0, B1, and B2, used in a well-known formula:

X = A0 + A1 * x + A2 * y

Y = B0 + B1 * x + B2 * y

where

A0 = X-offset

A1 = X-col

A2 = X-row

B0 = Y-offset

B1 = Y-col

B2 = Y-row

These parameters are detailed in the table below.

Warp-Affine process parameters

Parameter	Constant	Description
Direction of initialization		Direction in which the transformation will take place.
X-offset	A0	X-offset for the image-to-ground transformation.
X-col	A1	Column coefficient for the x-coordinate in the image-to-ground transformation.
X-row	A2	Row coefficient for the x-coordinate in the image-to-ground transformation.
Y-offset	B0	Y-offset for the image-to-ground transformation.
Y-col	B1	Column coefficient for the y-coordinate in the image-to-ground transformation.
Y-row	B2	Row coefficient for the y-coordinate in the image-to-ground transformation.
Alias		An alias for this process. An alias should uniquely identify the process in a process chain. You can edit this alias without affecting the process.

Warp-Affine process parameters

Warp-Grid process

The Warp-Grid process enables you to perform a two-dimensional warp based on a grid of points.

The parameters represent a regular grid of points in the output coordinate system, each point being associated with an x,y coordinate in the input coordinate system. The grid of points forms cells. For each output coordinate, an associated input coordinate is computed using bilinear interpolation within the associated cell. If a coordinate outside the grid is selected, a bilinear extrapolation of the nearest cell is performed.

The grid is described by either upper left corner (default) or lower left corner, number of rows and columns, and the (x,y) coordinates of each point within the grid.

Warp-Grid process parameters

Parameter	Description
Upper left X	The upper left x-coordinate of the grid.
Upper left Y	The upper left y-coordinate of the grid.
Number of columns	Number of columns in the grid.
Number of rows	Number of rows in the grid.
Size of each column	Size of each column in the grid.
Size of each row	Size of each row in the grid.
X values	Values of the x-coordinates, entered row wise. These values should be separated by a comma.
Y values	Values of the y-coordinates, entered row wise. These values should be separated by a comma.
Alias	An alias for this process. An alias should uniquely identify the process in a process chain.

Warp-Grid process parameters

Warp-SRS process

The Warp-SRS process allows you to transform coordinate systems. It enables ArcGIS Image Server to convert the request from the service coordinate system to the raster coordinate system.

Warp-SRS process parameters

Parameter	Description
Direction of initialization	Direction in which the transformation will take place.
Input SRS	The spatial reference system of the input points.
Output SRS	The spatial reference system to which the input points will be transformed.
Alias	An alias for this process. An alias should uniquely identify the process in a process chain.

Warp-SRS process parameters