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Hi

 

I'm trying to convert our DTM tiffs to a more weboptimized format.

I'm thinking of jpg, png, ecw, jpeg2000.

 

When I try to convert them to gray8 I loose the numbers behind the comma, because the rasterinterpretationcoercer converts from float to integer.

That's just not an option.

 

I also tried this:

 

The numericrasterizer gives an error:

NumericRasterizer (VectorToRasterFactory): No values were specified for either both WIDTH and HEIGHT or both X_CELL_SIZE and Y_CELL_SIZE. When any of WIDTH, HEIGHT, X_CELL_SIZE, Y_CELL_SIZE, INTERPRETATION_TYPE, BACKGROUND_COLOR, BACKGROUND_ALPHA, BACKGROUND_VALUE, or GROUND_EXTENTS is specified, values for either both WIDTH and HEIGHT or both X_CELL_SIZE and Y_CELL_SIZE must be provided.

Also tried the propertyextractor in serie with the rastercellcoercer and kept the attributes.

Then I get all rejected in the numericrasterizer.

Also this takes way to long. I have a lot of DTM tiles.

 

Can somebody point me into the right direction?

I've found a lot of info on the forum, but I could work it out yet.

 

Hi @koenvdw,

Most raster formats only support integer pixel values, including PNG, JPG, ECW and JPG2K. As well, jpeg and wavelet compression schemes are lossy, and will modify the values of your DTM points. GeoTIFF is one of the few that support float pixel values, so you may need to stay with that format.

However, there are techniques you can use to optimize your GeoTIFF. One method is to use lossless LZW compression when writing. Another is to tile and pyramid the files. Tiling arranges the pixels into smaller subimages within the main image, resulting in faster reading for smaller areas. Pyramids are lower resolution overviews that can be read instead of the entire image when viewing the full resolution isn't needed.

FME can convert your GeoTIFF images to add the lossless compression, tiling and pyramids, using a GeoTIFF to GeoTIFF conversion.

Hi @koenvdw,

Most raster formats only support integer pixel values, including PNG, JPG, ECW and JPG2K. As well, jpeg and wavelet compression schemes are lossy, and will modify the values of your DTM points. GeoTIFF is one of the few that support float pixel values, so you may need to stay with that format.

However, there are techniques you can use to optimize your GeoTIFF. One method is to use lossless LZW compression when writing. Another is to tile and pyramid the files. Tiling arranges the pixels into smaller subimages within the main image, resulting in faster reading for smaller areas. Pyramids are lower resolution overviews that can be read instead of the entire image when viewing the full resolution isn't needed.

FME can convert your GeoTIFF images to add the lossless compression, tiling and pyramids, using a GeoTIFF to GeoTIFF conversion.

Thx Dave

 

Do you have experience with cogeo.org?

Thx Dave

 

Do you have experience with cogeo.org?

Hi @koenvdw,

I took a look at the cogeo specifications, and FME can produce a suitable GeoTIFF file with the following output settings on the output feature type Properties:

Compression - Compression Method: JPEG

Tile - Create Tiled Files: Yes

Tile - Number of Columns per Tile: 512

Tile - Number of Rows per Tile: 512

Generate Pyramids enabled

Number of Levels to Generate: 5

Interpolation Type: Bicubic

Advanced - Photometric Interpretation: YCbCr

 

However, for height data, I think I would change the following settings:

Compression Method - DEFLATE

Interpolation Type - Nearest Neighbor

Photometric Interpretation: Auto

 

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