Changes between Initial Version and Version 1 of Ticket #5322


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Timestamp:
Dec 11, 2013, 9:55:54 AM (10 years ago)
Author:
warmerdam
Comment:

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  • Ticket #5322

    • Property Keywords GAT added
    • Property Status new → assigned
    • Property Component default → GDAL_Raster

  • Ticket #5322 – Description

    initial v1  
    11I would like to request the addition of support for reading and writing the Whitebox Geospatial Analysis Tools raster format. These data are stored using two files, a text (ASCII) header file with a .dep extension, and a similarly named binary data file with a .tas extension. An example of the header file is as follows:
    22
    3 Min:    17.0[[BR]]
     3{{{
     4Min:    17.0
     5Max:    503.0
     6North:  43.69812
     7South:  43.104858
     8East:   -79.749756
     9West:   -80.562744
     10Cols:   2927
     11Rows:   2136
     12Data Type:      FLOAT
     13Z Units:        not specified
     14XY Units:       not specified
     15Projection:     not specified
     16Data Scale:     continuous
     17Display Min:    17.0
     18Display Max:    503.0
     19Preferred Palette:      grey.pal
     20NoData: -32768.0
     21Byte Order:     LITTLE_ENDIAN
     22Metadata Entry: Created by the Import GeoTIFF (.tif) tool.
     23Metadata Entry: Created on Sat Dec 07 15;37;51 EST 2013
     24}}}
    425
    5 Max:    503.0[[BR]]
    6 
    7 North:  43.69812[[BR]]
    8 
    9 South:  43.104858[[BR]]
    10 
    11 East:   -79.749756[[BR]]
    12 
    13 West:   -80.562744[[BR]]
    14 
    15 Cols:   2927[[BR]]
    16 
    17 Rows:   2136[[BR]]
    18 
    19 Data Type:      FLOAT[[BR]]
    20 
    21 Z Units:        not specified[[BR]]
    22 
    23 XY Units:       not specified[[BR]]
    24 
    25 Projection:     not specified[[BR]]
    26 
    27 Data Scale:     continuous[[BR]]
    28 
    29 Display Min:    17.0[[BR]]
    30 
    31 Display Max:    503.0[[BR]]
    32 
    33 Preferred Palette:      grey.pal[[BR]]
    34 
    35 NoData: -32768.0[[BR]]
    36 
    37 Byte Order:     LITTLE_ENDIAN[[BR]]
    38 
    39 Metadata Entry: Created by the Import GeoTIFF (.tif) tool.[[BR]]
    40 
    41 Metadata Entry: Created on Sat Dec 07 15;37;51 EST 2013[[BR]]
    42 
    43 (Please note that the 'NoData' entry should not have the question mark appended to it in the above formatting.)
    4426
    4527The Display Min and Display Max entries in the .dep header file are used for display purposes only. These values determine the default display minimum and maximum values and can be edited for more effectual visualization of raster data sets. There are four allowable Data Type entries including 'double', indicating a grid of 64-bit floating-point values, 'float', indicating 32-bit floating-point data, 'integer', indicating a file containing 16-bit signed integer data, and 'byte' indicating a 8-bit signed byte. The byte data format is rarely used. The Data Scale entry has four allowable entries including 'continuous', 'categorical', 'Boolean', and 'rgb'. This entry affects how the raster image will be displayed, in particular whether it is displayed using the default continuous palette and an applied linear stretch between the display minimum and maximum values, or whether it will be displayed using the default qualitative palette with no linear stretch. Entity-type data (e.g. soil categories) should always be displayed using a qualitative palette. Notice that the data scale in the header file will be automatically updated when the user checks or unchecks the Apply Linear Stretch option on the Layer Properties tab. The data scale for an image is originally set programmatically by the tool used to create the image. Raster images with a data scale of 'rgb' are not displayed with a palette but rather are displayed using the 32-bit red-green-blue colour model (aRGB). RGB colour images are usually created from multispectral imagery using the Create Colour Composite tool or by importing an image.