How to view specific NASADEM files?

[claudiogeop]

How to view specific NASADEM files?
I have the following files with the extensions listed below and I would like to view them.

.aspect
.planc
.profc
.slope
.swb

[LP DAAC - jwilson]

Greetings,

The NASADEM_SC dataset at: https://lpdaac.usgs.gov/products/nasadem_scv001/ are generic binary files as well (like HGT).

Once we have additional guidance on how to view the following NASADEM extensions from our science data specialist, I will send it to you.
.aspect
.planc
.profc
.slope
.swb

Best regards,
Janice

[claudiogeop]

Greetings, I look forward to that return.


Best regards,
Cláudio

[LP DAAC - jwilson]

Greetings,
The NASADEM_SC data layers are considered generic binary files with no header information. These data files can be described manually for importing into most GIS software packages such as ArcGIS, ENVI or ERDAS and the open source MultiSpec software as well.

The .aspect and .slope binary files are described as:
3601 columns by 3601 rows
1 band
No header records or header bytes
Unsigned 16-bit integers
Byte order is IEEE, with most significant bit or big endian order

The .planc, .profc and .swb have the same characteristics with the exception of the data types:
The .planc and .profc are 32-bit floating point
The .swb is 8-bit or byte

We hope this helps! Let us know if you have any further questions.
Best regards,
Janice

[claudiogeop]

Perfectly, I will be carrying out some tests, once again thank you and if there is any difficulty return.

Best regards,
Cláudio

[claudiogeop]

I was able to open the images in MultiSpec regarding the .slope / .swb formats, unfortunately it did not come georeferenced. When I open the same .hgt file the month already has the location defined. Are these images not georeferenced in the original format?

[LP DAAC - jwilson]

Our subject matter expert sent the following: If only using MultiSpec – if so, not sure if it is possible to set the coordinates in MultiSpec
It is true, the NASADEM_SC data files are not geo-referenced and will need to be done manually as well.

This is also true for the NASADEM_SIM, NASADEM_SSP and NASADEM_SHHP datasets.

The coordinate system is considered to be geographic in decimal degrees of latitude and longitude
The coordinate system can also be defined as ESPG:4326 in most GIS software packages
The spatial resolution is 0.000277777777777778 decimal degrees
The data files are in tiles of 1 x 1 degrees

For an explanation to manually geo-reference the data files, let’s use the example of:
n32w105.slope (or .planc, .profc, .swb)

The “n32w105” in the filename refers to the lower left coordinate of the data file.
The other three corners can be determined by using the lower left coordinate:
LL = 32, -105
UL= 33, -105
UR = 33, -104
LR = 32, -104

Hopefully this helps!

[anatoliikukhar]

Hello, I'm trying to get slope angle data from a .slope file using python, but I'm getting large numbers. For example, I am trying to do this with a file from the NASADEM_SC.001 data set. What could I be doing wrong?


import numpy as np
import pandas as pd

with open('n49e030.slope', 'rb') as f:
data = np.fromfile(f, dtype=np.uint16)

df = pd.DataFrame(data.reshape(3601, 3601))
df



https://e4ftl01.cr.usgs.gov/MEASURES/NASADEM_SC.001/2000.02.11/

[LP DAAC - jwilson]

@anatoliikukhar I forwarded your question to our science team. I will reply once we hear back from the team.
Thank you,
Janice

[LP DAACx - dgolon]

Hello @anatoliikukhar Please apply the scale factor of 0.01.

Here is an updated script example:

import numpy as np
import pandas as pd

slope_file_path = 'path to file/n49e030.slope'
with open(slope_file_path, 'rb') as f:
slope_data = np.fromfile(f, dtype=np.uint16)

slope_grid = slope_data.reshape(3601, 3601)

# Apply the scale factor of 0.01 to convert the integer values to the desired scale
scaled_slope_grid = slope_grid * 0.01
slope_df = pd.DataFrame(scaled_slope_grid)
print(slope_df)


Thanks -- Danielle