Land-Sea mask not working properly

Microwave Toolbox
#1

Hello

we try to find dark areas on the sea from Sentinel-1 images. Hence we use SNAP Land-Sea Mask tool, that seems not to work properly.

Here is an image (D278) processed with SNAP Beta 8; as you can see, only a small part of land has been masked.

And more than that, using Land-Sea Mask in gpt does not work at all.

Any idea ?

Thanks for your help;

Christian

#2

By default the land/sea mask uses the SRTM to mask out areas just because this is the resource that is already available. The SRTM is only available at latitudes of ± 60.
Alternatively, you could try unchecking “use SRTM” in which case the rough ACE 5 min is used or you could import your own shoreline as a shape file and select that.

#3

Thank you for your reply

In fact, I have a second problem : Though it works now in SNAP with useSRTM set to false, when I try to run it with gpt tool, I get :

Error: com/bc/ceres/swing/figure/FigureStyle

I have seen that it is a know bug (Import Vector not working from gpt)

Have you got an idea about how long it will take to solve it ?

Thank you for your help.

Kind regards,
Christian

#4

Dear Luis,

any updates on this issue? I ran into the same problem with the Import vector operator executed on command line with either the Operator as well as a custom graph.

Best,
Andreas

#5

Ok, sorry for the long delay on this. It should now be fixed and will be in the release later this week.

#6

Just a follow on question - both mask types work ok for me now thanks, but i guess if you have an available shapefile then you should always use this? Or is a high res shapefile of the coast going to affect processing times. when compared with the SRTM

#7

Hello! I need to mask out land in Sentinel images of high latitude (SRTM is not work). Please tell me where can I get a shapefile for Arctic islands and how to apply it with SNAP. I can’t find an answer

#8

i don’t know where you would find the shapefile - but when you do find one :

  • highlight the image in the product explorer that you want to process
  • file - import - vector data - esri shapefile
  • then run the land/sea mask browsing to the vector file
  • make sure you invert the mask. if you don’t it will mask out the water.
1 Like
#9

Using your own shapefile shouldn’t affect performance that much.

1 Like
#10

Hi Lveci,

Is it possible to use the Land-sea mask (use my own vector as mask) in the graph builder? I could’t find my vector in the graph builder.

Best,
Jasmine

#12

def land_sea_mask(ec,datestamp):
params = HashMap()
params.put(‘useSRTM’, True)
params.put(‘landMask’, True)
params.put(‘InvertGeometry’,False)
params.put(‘shorelineExtension’,‘10’)
lsm= GPF.createProduct(‘Land-Sea-Mask’, params, ec)
write_product(ec, os.path.join(output, ‘{}_Orb_Cal_ML_TF_Stack_Spk_EC_Mask’.format(datestamp)), format=‘GeoTIFF’)
return lsm

I am not sure why my file is not masked