How to use DEM data above N60°

[DJschao]

Hi everyone,

When I used ISCE to process Sentinel-1A datas on the North Slope of Alaska, I found that SRTM has no data at all. However, DEM data is essential for InSAR processing. How can I solve this problem?

In addition, I downloaded ASTER GDEM data. Can this data be used in ISCE? At the same time, how can I convert it to DEM format recognized by ISCE.

Thanks!

[yuankailiu]

This is a Discussions from long time ago. I hope you figure out how to do it. If not, here are some tips from me.

You can check something from the following sources. I have not worked on Alaska before. So maybe you can also asked others:

• https://data.usgs.gov/datacatalog/data/USGS:e250fffe-ed32-4627-a3e6-9474b6dc6f0b
• https://scholarworks.alaska.edu/handle/11122/10875

After downloading the file, GDAL can help to handle the DEM raster further. You can crop, resample, and export your downloaded DEM to a new raster format that is readable for ISCE. Usually by -of ISCE or --format ISCE depending on different GDAL scripts. For example, for gdalwarp, I can do:

gdalwarp -t_srs EPSG:4326 NETCDF:"your_downloaded_dem.nc" ./dem/outputDEM.wgs84 -te 150 -78 173 -72 -r cubicspline -of ISCE

You can also read your initial downloaded DEM and output into several resolutions. Below is my script to handle this particular DEM for Antartica:

#!/bin/bash

### To extract REMA dem .tif files from a batch of *.gz.tar
# ------------------------------------------------------------------------------------------------------------------
### How to get REMA data
###     + REMA main website: https://www.pgc.umn.edu/data/rema/
###     + REMA explorer to see index of a certain DEM tile: https://livingatlas2.arcgis.com/antarcticdemexplorer/
###     + use wget to download *.gz.tar: https://data.pgc.umn.edu/elev/dem/setsm/REMA/mosaic/v1.1/
###             can copy-paste your urls to a text file and parallelize the download by running
###             `parallel -a rema_mosaic_tile_urls.txt --jobs 8 wget`
###
### The output durectory is the current path
# ------------------------------------------------------------------------------------------------------------------
###     ykliu @ 2022-02-08


outfile="dem_david.wgs84"


## Tiff files extraction
mkdir -p tiff
for pkg in *.tar.gz; do
        # Set comma as delimiter
        IFS='.'

        #Read the split words into an array based on comma delimiter
        read -a str <<< "$pkg"

        #Print the splitted words
        echo "Index name : ${str[0]}"
        #echo "gz ext: ${str[1]}"
        #echo "tar ext : ${str[2]}"

        # untar the *.dem.tif files to current path
        tar -xvf "${str[0]}.${str[1]}.${str[2]}" "${str[0]}*dem.tif"
done

mv *.dem.tif tiff



## The `merged.tif` is the stitched DEM formed by using GDAL; fill -9999 for nodata
#cd tiff
#gdal_merge.py -init -9999 -v -n -9999 -o merged.tif *.tif -of ISCE
#cd ..


##################  Starting handling the downloaded DEM ##################
## Transform coordinate system; Downsample the dem
mkdir -p dem_1_arcsec/ dem_3_arcsec/ dem_30_arcsec/ dem/
gdalwarp -t_srs EPSG:4326 tiff/merged.tif dem_1_arcsec/tmp.dem  -r cubicspline -tr 0.000277778 0.000277778 -of ISCE
gdalwarp -t_srs EPSG:4326 tiff/merged.tif dem_3_arcsec/tmp.dem  -r cubicspline -tr 0.000833333 0.000833333 -of ISCE
gdalwarp -t_srs EPSG:4326 tiff/merged.tif dem_30_arcsec/tmp.dem -r cubicspline -tr 0.008333333 0.008333333 -of ISCE


## Mask nan and zeros
gdal_calc.py -A dem_1_arcsec/tmp.dem  --outfile="dem_1_arcsec/tmp2.dem"  --calc="A*(A>-9000)" --NoDataValue=nan --format ISCE
gdal_calc.py -A dem_3_arcsec/tmp.dem  --outfile="dem_3_arcsec/tmp2.dem"  --calc="A*(A>-9000)" --NoDataValue=nan --format ISCE
gdal_calc.py -A dem_30_arcsec/tmp.dem --outfile="dem_30_arcsec/tmp2.dem" --calc="A*(A>-9000)" --NoDataValue=nan --format ISCE
gdalwarp -srcnodata 0 -dstnodata nan dem_1_arcsec/tmp2.dem  "dem_1_arcsec/${outfile}"  -of ISCE
gdalwarp -srcnodata 0 -dstnodata nan dem_3_arcsec/tmp2.dem  "dem_3_arcsec/${outfile}"  -of ISCE
gdalwarp -srcnodata 0 -dstnodata nan dem_30_arcsec/tmp2.dem "dem_30_arcsec/${outfile}" -of ISCE


## fix image xml file
fixImageXml.py -i "dem_1_arcsec/${outfile}" -f
fixImageXml.py -i "dem_3_arcsec/${outfile}" -f
fixImageXml.py -i "dem_30_arcsec/${outfile}" -f


## remove tmp files
rm -rf dem_*_arcsec/tmp*.dem*

echo "Complete the DEM outputs"

[sisi-ali]

Hi Dear,
can you download DEM ?
if you can , could you help me please?

[riyasmjgeo]

I downloaded the 100m REMA (void-filled) covering the entire Antarctic continent. I wanted to use it for ISCE.
I have converted it to ISCE format using gdalwarp -t_srs EPSG:4326 REMA_100m_dem.tif rema_isce -of ISCE
However, I am getting an error while using it.
I don't understand the error corrupted size vs. prev_size. Can you please help @yuankailiu or anyone?

Error is as below

  << Geoid Correction I2 SRTM>>

Jet Propulsion Laboratory - Radar Science and Engineering


Sampling Geoid at grid points -  Longitude Samples:  3603 Latitude Lines:   127
Corner Geoid Heights (m) =  -61.92 -61.83 -41.22  19.75

Correcting data to geoid height...

At line:      512
At line:     1024
At line:     1536
At line:     2048
At line:     2560
At line:     3072
At line:     3584
At line:     4096
At line:     4608
corrupted size vs. prev_size
Aborted (core dumped)

The meta-data of the DEM used

$ gdalinfo rema_isce
Driver: ISCE/ISCE raster
Files: rema_isce
       rema_isce.aux.xml
       rema_isce.xml
Size is 143952, 4958
Coordinate System is:
GEOGCRS["WGS 84",
    DATUM["World Geodetic System 1984",
        ELLIPSOID["WGS 84",6378137,298.257223563,
            LENGTHUNIT["metre",1]]],
    PRIMEM["Greenwich",0,
        ANGLEUNIT["degree",0.0174532925199433]],
    CS[ellipsoidal,2],
        AXIS["geodetic latitude (Lat)",north,
            ORDER[1],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["geodetic longitude (Lon)",east,
            ORDER[2],
            ANGLEUNIT["degree",0.0174532925199433]],
    ID["EPSG",4326]]
Data axis to CRS axis mapping: 2,1
Origin = (-179.999982151397489,-57.514257918574877)
Pixel Size = (0.002500818414793,-0.002500835787499)
Metadata:
  AREA_OR_POINT=Area
  DataType=Generic
Corner Coordinates:
Upper Left  (-179.9999822, -57.5142579) (179d59'59.94"W, 57d30'51.33"S)
Lower Left  (-179.9999822, -69.9134018) (179d59'59.94"W, 69d54'48.25"S)
Upper Right ( 179.9978303, -57.5142579) (179d59'52.19"E, 57d30'51.33"S)
Lower Right ( 179.9978303, -69.9134018) (179d59'52.19"E, 69d54'48.25"S)
Center      (  -0.0010759, -63.7138298) (  0d 0' 3.87"W, 63d42'49.79"S)
Band 1 Block=143952x1 Type=Float32, ColorInterp=Undefined
  NoData Value=-3.40282306073709653e+38
  Metadata:
    RepresentationType=ATHEMATIC

TopsApp.xml

<topsApp>
  <component name="topsinsar">
    <property name="Sensor name">SENTINEL1</property>
      <property name="do unwrap">True</property>
      <property name="unwrapper name">snaphu_mcf</property>
      <property name="filter strength">0.4</property>
      <property name="do ESD">True</property>
      <property name="azimuth looks">4</property>
      <property name="range looks">25</property>
      <property name="do denseoffsets">True</property>
      <property name="demfilename">./rema_isce</property>

    <component name="reference">
      <property name="auxiliary data directory">/home/luis/Work/Sentinel-1_aux</property>
      <property name="polarization">'hh'</property>
      <property name="safe">S1A_IW_SLC__1SSH_20220122T154456_20220122T154526_041575_04F1F2_0BC7.zip</property>
      <property name="orbit directory">./</property>
      <property name="output directory">master</property>
    </component>

    <component name="secondary">
      <property name="auxiliary data directory">/home/luis/Work/Sentinel-1_aux</property>
      <property name="polarization">'hh'</property>
      <property name="orbit directory">./</property>
      <property name="output directory">slave</property>
      <property name="safe">S1A_IW_SLC__1SSH_20220203T154455_20220203T154525_041750_04F7E2_B1BC.zip</property>
    </component>
  </component>
</topsApp>

[riyasmjgeo]

I cropped the DEM to AOI (roughly), and it worked. I believe it was some memory constraint.

[sisi-ali]

Hi, dear riyasmjgeo
I am working in ISCE software,
I want to download Dem but I can’t download.
I have an error:
isce.contrib.demUtils.DemStitcher - WARNING - There was a problem in retrieving the file http://e4ftl01.cr.usgs.gov/MEASURES/SRTMGL1.003/2000.02.11/N30E048.SRTMGL1.hgt.zip. Exception

would like help me please.

[sisi-ali]

[riyasmjgeo]

Is your .netrc file is valid and provided required permissions?

[sisi-ali]

hi dear, thank you for replying to me:) I have been working for 2 years, but I cant download Dem I'm using python version 3.9 and ISCE2 could you help me please, ‫‪Riyas MJ‬‏ ***@***.***‬‏> در تاریخ چهارشنبه ۳ اوت ۲۰۲۲ ساعت ۸:۱۸ نوشت:‬

…

[image: 081fa3a8-7053-4f1e-b756-770d5cc99d41] <https://user-images.githubusercontent.com/108397906/182485236-40fdde16-dbbf-449d-b42e-4b800fe37c31.jpg> Is your *.netrc* file is valid and provided required permissions? — Reply to this email directly, view it on GitHub <#490 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZ3AKUVR5UNWZVT3K4VPXGDVXHT2VANCNFSM5WDOALKQ> . You are receiving this because you commented.Message ID: ***@***.***>

[sisi-ali]

hi What is the solution to download and use Ace software? ‫‪sedigheh alihasani‬‏ ***@***.***‬‏> در تاریخ پنجشنبه ۴ اوت ۲۰۲۲ ساعت ۱۱:۵۲ نوشت:‬

…

Hi dear Thanks for the answer. I can't download DEM. This is my problem .I’m using ISCE2. my study area is 30,33:47:50 ‫‪sedigheh alihasani‬‏ ***@***.***‬‏> در تاریخ چهارشنبه ۳ اوت ۲۰۲۲ ساعت ۱۱:۲۱ نوشت:‬ > hi dear, > thank you for replying to me:) > I had been working for 2 years, but i cant download dem > i'm using python version 3.9 and ISCE2 > could you help me please, > > > ‫‪Riyas MJ‬‏ ***@***.***‬‏> در تاریخ چهارشنبه ۳ اوت ۲۰۲۲ > ساعت ۸:۱۸ نوشت:‬ > >> [image: 081fa3a8-7053-4f1e-b756-770d5cc99d41] >> <https://user-images.githubusercontent.com/108397906/182485236-40fdde16-dbbf-449d-b42e-4b800fe37c31.jpg> >> >> Is your *.netrc* file is valid and provided required permissions? >> >> — >> Reply to this email directly, view it on GitHub >> <#490 (reply in thread)>, >> or unsubscribe >> <https://github.com/notifications/unsubscribe-auth/AZ3AKUVR5UNWZVT3K4VPXGDVXHT2VANCNFSM5WDOALKQ> >> . >> You are receiving this because you commented.Message ID: >> ***@***.***> >> >

[riyasmjgeo]

Hi,
Make sure the .netrc file is correct with proper permission.
Refer 3.5: https://github.com/isce-framework/isce2#notes-on-digital-elevation-models

[sisi-ali]

Hi dear Thanks for the answer. I can't download DEM. This is my problem .I’m using ISCE2. my study area is 30,33:47:50 ‫‪sedigheh alihasani‬‏ ***@***.***‬‏> در تاریخ چهارشنبه ۳ اوت ۲۰۲۲ ساعت ۱۱:۲۱ نوشت:‬

…

hi dear, thank you for replying to me:) I had been working for 2 years, but i cant download dem i'm using python version 3.9 and ISCE2 could you help me please, ‫‪Riyas MJ‬‏ ***@***.***‬‏> در تاریخ چهارشنبه ۳ اوت ۲۰۲۲ ساعت ۸:۱۸ نوشت:‬ > [image: 081fa3a8-7053-4f1e-b756-770d5cc99d41] > <https://user-images.githubusercontent.com/108397906/182485236-40fdde16-dbbf-449d-b42e-4b800fe37c31.jpg> > > Is your *.netrc* file is valid and provided required permissions? > > — > Reply to this email directly, view it on GitHub > <#490 (reply in thread)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/AZ3AKUVR5UNWZVT3K4VPXGDVXHT2VANCNFSM5WDOALKQ> > . > You are receiving this because you commented.Message ID: > ***@***.***> >