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Image World File Format

 

World files are companion files to geospatial images that contain spatial reference information to locate the image within its projection.

 

Please Note: the projection of the image must match that of the map in Hydro GeoAnalyst 12.0; on-the-fly Image reprojection is not currently supported.

 

Filename

In order to work with its associated image file, the worldfile must be located in the same folder as the image and have the same filename.  The file extention must be as follows:

Image File Type/Extension

Associated World File Extention

.BMP

.BPW

.GIF

.GFW

.JPG

.JPW

.PNG

.PGW

.TIF

.TFW

 

Contents

An ASCII world File consists of an ASCII text file with six items, each on a separate line:

 

Line

Symbol

Description

1

Δx

pixel size in the x-direction in map units (typically meters or feet)

2

θy

rotation/skew about y-axis

3

θx

rotation/skew about x-axis

4

Δy

pixel size in the y-direction in map units (typically meters or feet). The value is typically negative to indicate that the first pixel of the image/raster is located at the top/North

5

x0

x-coordinate of the center of the first (typically leftmost/East) pixel

6

y0

y-coordinate of the center of the first (typically topmost/North) pixel

 

Example

The image used in the Creating Maps called Basemap.tif has an associated world file (Basemap.tfw) with the following contents based on the UTM Zone 17N, NAD1983, projection in meters (EPSG 26917):

 

 

2.0000000000

0.0000000000

0.0000000000

-2.0000000000

532001.0000000000

4816499.0000000000

 

 

 


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