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[WPS][geogrid]SRTM too big for convert_geotiff

Z

Zhang_async

New member
Hello everyone,

I'm a freshman and currently working with WPS.

I’m using the convert_geotiff module to convert my SRTM elevation data (in TIFF format) into binary files, as I need high-resolution data.

However, when I ran convert_geotiff [data.tif], my Ubuntu system ran out of memory and became unresponsive. I suspect this is because the TIFF file is too large (6.5 GB). To resolve this, I cropped the TIFF to a smaller area that only covers my innermost domain (d03). This time, convert_geotiff successfully generated the binary files and the index file. I then modified the GEOGRID.TBL, and geogrid.exe ran without issues.

But when I checked the geo_em.d01 file, I noticed that only a small portion of the domain was filled with DEM data, while the rest appeared as "no data".

To summarize, I’m wondering which approach would be better:

1. Find an alternative method to convert the large TIFF file
2. Keep using the cropped DEM and find a way to interpolate low-resolution DEM data into the "no data" areas.

Thank you for any comments or suggestions!
 
Hi,
One alternative is that, you can crop TIFF to several smaller adjacent areas with the central area over your child domain. Then you can run geogrid.exe to process these 'tile' files. A good example is the available WPS static terrain height data, which is composed of multiple 'tiles'.
Hope this is helpful for you.
 
Ming Chen said:
Hi,
One alternative is that, you can crop TIFF to several smaller adjacent areas with the central area over your child domain. Then you can run geogrid.exe to process these 'tile' files. A good example is the available WPS static terrain height data, which is composed of multiple 'tiles'.
Hope this is helpful for you.
Click to expand...
Hi Chen,
Thanks for your reply. To confirm, should I only keep the central area's index file, or retain all of them?
 
Ming Chen said:
The index file should be same for all 'tiles'. Note that the size of individual 'tile' should also be same. More detailed information about the static input data can be found at Chapter 3: WRF Standard Initialization
Click to expand...
Hi Chen,

I've imported all 174 of my cropped TIFF files into a general folder. However, when I process them one by one, each output file overwrites the last because the output filename remains the same.

Could you please advise on how to resolve this?

Thanks.
 
The name of each 'TILE' should follow the rule described in Chapter 3: WRF Standard Initialization, which states that,
Code: 
When a data set is given in several pieces, each of the pieces may be formed as a regular rectangular array, and each array may be written to a separate
file. In this case, the relative locations of the arrays are determined by the range of x- and y-indices in the file names for each of the arrays. It is important 
to note, however, that every tile in a data set must have the same x- and y-dimensions, and that tiles of data within a data set must not overlap; 
furthermore, all tiles must start and end on multiples of the index ranges. For example, the global 30-second USGS topography data set is divided into
arrays of dimension 1200 ´ 1200, with each array containing a 10-degree ´ 10-degree piece of the data set; the file whose south-west corner is located at
(90S, 180W) is named 00001-01200.00001-01200, and the file whose north-east corner is located at (90N, 180E) is named 42001-43200.20401-21600.
 
Ming Chen said:
The name of each 'TILE' should follow the rule described in Chapter 3: WRF Standard Initialization, which states that,
Code: 
When a data set is given in several pieces, each of the pieces may be formed as a regular rectangular array, and each array may be written to a separate
file. In this case, the relative locations of the arrays are determined by the range of x- and y-indices in the file names for each of the arrays. It is important 
to note, however, that every tile in a data set must have the same x- and y-dimensions, and that tiles of data within a data set must not overlap; 
furthermore, all tiles must start and end on multiples of the index ranges. For example, the global 30-second USGS topography data set is divided into
arrays of dimension 1200 ´ 1200, with each array containing a 10-degree ´ 10-degree piece of the data set; the file whose south-west corner is located at
(90S, 180W) is named 00001-01200.00001-01200, and the file whose north-east corner is located at (90N, 180E) is named 42001-43200.20401-21600.
Click to expand...
Thanks for the details.
I've reviewed the requirements, but with the number of files I have, manual renaming isn't really feasible. Is there another way to batch process. And, Is it okay to only update the child domain?
 
You can try to create data only for the child domain....

Out software engineers handle the creation of static data 'TILES'. I will ask around and get back to you if I can find some helpful information.
 
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