Global Mapper Pro

Extracting water bodies using Raster Calculator & (NIR,R,G) + (R,G,B)?

digitalaviator
digitalaviator Global Mapper UserTrusted User
edited May 2015 in Raster Data
I've got a GIS project I've spent the last 8 years working on mapping every water body by hand in Photoshop. But I'm thinking it would be much easier and faster to work with the GM15/16 Raster Calculator.

I'm wondering if anyone has any clues how to accomplish this task.

Raster Image 1:

Band 1 - Near Infra Red
Band 2 - Red
Band 3 - Green

Raster Image 2:

Band 1 - Red
Band 2 - Green
Band 3 - Blue

on top of that I have NHD-HD data I could potentially use to help creatively refine the NDVI/NDWI data further but I'm not as yet quite sure how.

Does anyone have any ideas? My only other option investing in thousands of worth of software such as Erdas Imagine etc. which I don't really have the budget for.

Comments

  • nlneilson
    nlneilson Global Mapper User Trusted User
    edited December 2014
    I've got a GIS project I've spent the last 8 years working on mapping every water body by hand in Photoshop.

    That is a good question and you have done much work with Photoshop.
    The same question has been asked several times on the NASA WWJ forums with no viable answer.
    If you find a way please let us know. You could try the contour function with an altitude of 0.0 MSL and then correct that using Photoshop or whatever which would still be a lot of work.

    How close ar you trying to get ??
    I thought 'Imagine' had a trial version you could tinker with.

    Neil
  • digitalaviator
    digitalaviator Global Mapper User Trusted User
    edited December 2014
    I've been considering Imagine and planning to have a tinker. I do have a possible work around, at least for an area the size of an island and am running tests now, but that will only work on USA data or possibly European data as well.

    It should technically give a better rendition of the water data *in theory* but I'm still running tests.
  • digitalaviator
    digitalaviator Global Mapper User Trusted User
    edited December 2014
    Oh I have done a lot of work in photoshop in the past as well. My background is professional film/tv production and have years of imaging experience.

    I'm trying to get as accurate as possible to the water in both the CIR and RGB as possible. The biggest challenge I have is with rogue data in building and mountain/tree shadows.

    In short I've spent 8 years hand mapping every single pixel of water for Oahu. I'm close to cracking bypassing all those years of work and getting something that's actually quite accurate. I just have to figure out how to remove the extraneous data quickly and automatically.
  • Dinesh Patil
    Dinesh Patil Global Mapper User
    edited May 2015
    I can help you out for this.I did some work with this and success to create features automaticaly from images you said.
    I have written Global Mapper scripts for this.I am having 15 years of exeprience in GIS/Photogrammetry.If possible send small sample image.
  • nlneilson
    nlneilson Global Mapper User Trusted User
    edited May 2015
    I can help you out for this.I did some work with this and success to create features automaticaly from images you said.
    I have written Global Mapper scripts for this.I am having 15 years of exeprience in GIS/Photogrammetry.If possible send small sample image.

    I have tiled all of the FAA Charts that were originally in the geotif format.
    I would like to tile the NOAA Nautical Charts.

    Nautical Charts & Pubs

    I have not been able to convert those to the geotif format.
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