Data type conversion
From AWF-Wiki
(Difference between revisions)
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We may change the data type (or radiometric resolution) of a raster layer. | We may change the data type (or radiometric resolution) of a raster layer. | ||
| − | # Click the {{button|text=Add raster layer}} [[Image:QGIS_2.0_addrast.png|20px]] and select a single band file ''/geodata/raster/s2/Subset_S2A_MSIL2A_20170619T_B03.tif''. This is a spectral green band with the data type '''UInt16 - Sixteen bit unsigned integer | + | # Click the {{button|text=Add raster layer}} [[Image:QGIS_2.0_addrast.png|20px]] and select a single band file ''/geodata/raster/s2/Subset_S2A_MSIL2A_20170619T_B03.tif''. This is a spectral green band with the data type '''UInt16 - Sixteen bit unsigned integer''' with the value range 0 to 65535 (Check the [[Raster metadata]]). We would like to convert the raster to data type '''Byte - eight bit unsigned integer''', value range 0 to 255. |
# Click {{button|text=Open}}. | # Click {{button|text=Open}}. | ||
# In processing toolbar, type {{typed|text=Rescale}} into the search field to find the {{button|text=Orfeo Toolbox --> Image Manipulation --> Rescale Image)}} tool. Open it with a double click. Specify a new output file name as shown in the screenshot. | # In processing toolbar, type {{typed|text=Rescale}} into the search field to find the {{button|text=Orfeo Toolbox --> Image Manipulation --> Rescale Image)}} tool. Open it with a double click. Specify a new output file name as shown in the screenshot. | ||
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[[File:Qgis_rescale.png|400px]] | [[File:Qgis_rescale.png|400px]] | ||
| − | The output Image raster is now recoded to correct eight bit data range but the data type is now '''Float32 - Thirty two bit floating point'''. Note, the | + | The output Image raster is now recoded to correct eight bit data range but the data type is now '''Float32 - Thirty two bit floating point'''. Note, the Output pixel type option {{typed|text=uint8}} currently does not work! |
# In the processing toolbar, type {{typed|text=Convert data}} into the search field to find the {{button|text=SAGA --> Raster tools --> Convert data storage)}} tool. Open with a double click. | # In the processing toolbar, type {{typed|text=Convert data}} into the search field to find the {{button|text=SAGA --> Raster tools --> Convert data storage)}} tool. Open with a double click. | ||
Specify | Specify | ||
Revision as of 12:29, 29 October 2018
We may change the data type (or radiometric resolution) of a raster layer.
- Click the Add raster layer
and select a single band file /geodata/raster/s2/Subset_S2A_MSIL2A_20170619T_B03.tif. This is a spectral green band with the data type UInt16 - Sixteen bit unsigned integer with the value range 0 to 65535 (Check the Raster metadata). We would like to convert the raster to data type Byte - eight bit unsigned integer, value range 0 to 255.
- Click Open.
- In processing toolbar, type Rescale into the search field to find the Orfeo Toolbox --> Image Manipulation --> Rescale Image) tool. Open it with a double click. Specify a new output file name as shown in the screenshot.
The output Image raster is now recoded to correct eight bit data range but the data type is now Float32 - Thirty two bit floating point. Note, the Output pixel type option uint8 currently does not work!
- In the processing toolbar, type Convert data into the search field to find the SAGA --> Raster tools --> Convert data storage) tool. Open with a double click.
Specify
- Data storage type: [1] unsigned 1 byte integer
- Converted grid: a new output file name. Click Run.
