Project Raster (Data Management)
Summary
Transforms the raster dataset from one projection to another.
Usage
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The coordinate system defines how your raster data is projected.
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This tool guarantees that the error is less than half a pixel.
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You are able to choose a preexisting spatial reference, import it from another dataset, or create a new one.
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You may want to change the coordinate system so your data is all in the same projection.
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This tool can only output a square cell size.
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You can save your output to BIL, BIP, BMP, BSQ, DAT, Esri Grid, GIF, IMG, JPEG, JPEG 2000, PNG, TIFF, or any geodatabase raster dataset.
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When storing your raster dataset to a JPEG file, a JPEG 2000 file, or a geodatabase, you can specify a Compression type and Compression Quality within the Environment Settings.
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Projects a raster dataset into a new spatial reference using a bilinear interpolation approximation method, which projects pixels on a coarse mesh grid and uses bilinear interpolation between the pixels.
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The NEAREST option, which performs a nearest neighbor assignment, is the fastest of the four interpolation methods. It is primarily used for categorical data, such as a land-use classification, because it will not change the cell values. It is not recommended that NEAREST be used for continuous data, such as elevation surfaces.
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The BILINEAR option uses bilinear interpolation to determine the new value of a cell based on a weighted distance average of the four nearest surrounding cells. The CUBIC option uses cubic convolution to determine the new cell value by fitting a smooth curve through the surrounding points. These are the most appropriate choices for continuous data, but may cause some smoothing. Note that cubic convolution may result in the output raster containing values outside the range of the input raster. It is not recommended that BILINEAR or CUBIC be used with categorical data because different cell values may be introduced, which may be undesirable.
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The cells of the raster dataset will be square and of equal area in map coordinate space, although the shape and area a cell represents on the surface of the earth will never be constant across a raster. This is because no map projection can preserve both shape and area simultaneously. The area represented by the cells will vary across the raster. Therefore, the cell size and the number of rows and columns in the output raster may change.
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Always specify an output cell size, unless you are projecting between spherical (latitude–longitude) coordinates and a planar coordinate system where you don't know what an appropriate cell size would be.
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The default cell size of the output raster is determined from the projected cell size at the center of the output raster. This is also (usually) the intersection of the central meridian and latitude of true scale and is the area of least distortion. The boundary of the input raster is projected, and the minimum and maximum extents dictate the size of the output raster. Each cell is projected back to the input coordinate system to determine the cell's value.
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The geographic transformation is an optional parameter when the input and output coordinate systems have the same datum. If the input and output datum are different, a geographic transformation needs to be specified.
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The registration point allows you to specify the origin point for anchoring the output cells. All output cells will be an interval of the cell size away from this point. This point does not have to be a corner coordinate or fall within the raster dataset. If a Snap Raster is set in the Environment Settings, the registration point will be ignored.
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CLARKE 1866 is the default spheroid if it is not inherent to the projection (such as NEWZEALAND_GRID) or another is specified with the SPHEROID subcommand.
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The snap raster setting will take priority over the registration point, if both are set.
Syntax
| Parameter | Explanation | Data Type |
in_raster |
The input raster dataset. | Mosaic Layer; Raster Layer |
out_raster |
The output raster dataset to be created. When storing the raster dataset in a file format, you need to specify the file extension:
When storing a raster dataset in a geodatabase, no file extension should be added to the name of the raster dataset. When storing your raster dataset to a JPEG file, a JPEG 2000 file, a TIFF file, or a geodatabase, you can specify a compression type and compression quality. | Raster Dataset |
out_coor_system |
The coordinate system to which the input raster will be projected. The default value is set based on the Output Coordinate System environment setting. Valid values for this parameter are
| Coordinate System |
resampling_type (Optional) |
The resampling algorithm to be used. The default is NEAREST.
The NEAREST and MAJORITY options are used for categorical data, such as a land-use classification. The NEAREST option is the default since it is the quickest and also because it will not change the cell values. Do not use NEAREST or MAJORITY for continuous data, such as elevation surfaces. The BILINEAR option and the CUBIC option are most appropriate for continuous data. It is not recommended that BILINEAR or CUBIC be used with categorical data because the cell values may be altered. | String |
cell_size (Optional) |
The cell size for the new raster dataset. The default cell size is the cell size of the selected raster dataset. | Analysis Cell Size |
geographic_transform (Optional) |
The transformation method used between two geographic systems or datums. The geographic transformation is optional when the input and output coordinate systems have the same datum. If the input and output datum are different, a geographic transformation needs to be specified. For information on each supported geographic (datum) transformations, see the geographic_transformations.pdf located in <install location>\ArcGIS\Desktop10.1\Documentation. | String |
Registration_Point (Optional) |
The x and y coordinates (in the output space) used for pixel alignment. The registration point works similar to the concept of snap raster. Instead of snapping the output to an existing raster cell alignment, the registration point allows you to specify the origin point for anchoring the output cells. All output cells will be an interval of the cell size away from this point. This point does not have to be a corner coordinate or fall within the raster dataset. The Snap Raster environment setting will take priority over the Registration Point parameter. Therefore, if you want to set the registration point, make sure that Snap Raster is not set. | Point |
in_coor_system (Optional) |
The coordinate system of the input raster dataset. | Coordinate System |
Code Sample
This is a Python sample for the ProjectRaster tool.
import arcpy
from arcpy import env
arcpy.ProjectRaster_management("c:/data/image.tif", "c:/output/reproject.tif",\
"World_Mercator.prj", "BILINEAR", "5",\
"NAD_1983_To_WGS_1984_5", "#", "#")
This is a Python script sample for the ProjectRaster tool.
##====================================
##Project Raster
##Usage: ProjectRaster_management in_raster out_raster out_coor_system {NEAREST | BILINEAR
## | CUBIC | MAJORITY} {cell_size} {geographic_transform;
## geographic_transform...} {Registration_Point} {in_coor_system}
try:
import arcpy
arcpy.env.workspace = r"C:/Workspace"
##Reproject a TIFF image with Datumn transfer
arcpy.ProjectRaster_management("image.tif", "reproject.tif", "World_Mercator.prj",\
"BILINEAR", "5", "NAD_1983_To_WGS_1984_5", "#", "#")
##Reproject a TIFF image that does not have a spatial reference
##Set snapping point to the top left of the original image
snapping_pnt = "1942602 304176"
arcpy.ProjectRaster_management("nosr.tif", "project.tif", "World_Mercator.prj", "BILINEAR",\
"5", "NAD_1983_To_WGS_1984_6", snapping_pnt,\
"NAD_1983_StatePlane_Washington_North.prj")
except:
print "Project Raster example failed."
print arcpy.GetMessages()