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How to increase raster transparency

Hello everyone! I'm following the steps of this video list and I would like to know how to smooth the display of my raster as in the image below taken from the video.

My image has very expressive colors and it is difficult to highlight the buildings and to work with it.

  • Hi Luis,

    I wonder if your question is about transparency in Raster files or if your question is more related about choose suitable (value) ranges in Gridded layers generated in OpenFlows FLOOD.

    NOTE: There is a known issue in FLOOD with some types of DTM Raster files (Geo Tiff ) where is not possible to visualize the color scale, but FLOOD is able to process the information (i.e. elevation) to generate a DTM. If issue is related to this, not much to add or explain.

    On the other hand, when you generate a ‘grid data’ layer in FLOOD, in the properties dialog you have transparency option (where 255 is maximum and 0 will be invisible). See image. That allows you to have transparency.

     

    If question is not related to transparency itself… There are some advices in grid data visualization than I can give you and are related to choose or configure a proper values range. For example, when you initially generate a ‘Runoff_Water Column’ layer you will see a non-informative image like this (an uniform blue stain based on gradient style configuration). 

     

     But for this 'water column' layer you can change the style type to Color Range you will have a better grid data visualization.

     

     Then you can have a better picture of the simulation results (water column elev, in this case).

    Not sure, if these instructions help. But once you have 'Grid Data' for elevation, manning, CN, etc, OpenFlows FLOOD offer different visualization options.

    Rgds,

    Juan Carlos Gutierrez

    Product Success Consultant – LA Region

    Juan Carlos Gutiérrez Araújo I.C. M.Sc.

    Senior Product Consultant - Bentley Systems Latin America

  • Hi Juan,

    Thank you for your help. It did help me. I was able to change it to the DMT as I would like, but I have not yet found how to change the transparency of this layer. If possible, I would like to leave it as the image from the video (second image from the post). Thanks!



  • Hi Luis,

    Well, if you work with the source raster file (i.e. a Geotiff file) there are not many options related to configure visibility and/or transparency.

    You should consider that the algorithm on FLOOD (aka Mohid Land) is based on finite volumen and for that reason you need to create a computational grid for your model and different parameters should be also transformed into a Grid Data format.

    Usually when you work with a DTM based on a raster file (source), you need go to Toolbox > Grid Data > Create Grid Data from Raster and then you will create a 'Gridded DTM' layer where you will have the options that I have explained before including transparency and color range options.

    I am not sure about a specific step on the video/demonstration but probably this is based on a transformed digital terrain model in a grid data format.

    Hope that helps. In addition, I will comment your question to other colleague in order to give you another clue.

    Rgds,

    Juan Carlos Gutiérrez Araújo I.C. M.Sc.

    Senior Product Consultant - Bentley Systems Latin America

  • Hello Luis,

    Another option to be able to render the raster data with a color scale is to create (e.g. in QGIS) a virtual raster (.vrt) and then open the VRT file in FLOOD. 

    In QGIS you can load the TIF (or other raster format) and use the GDAL tool in Tools -> GDAL -> Raster miscellaneous -> Build virtual raster and follow the basic configuration options and export the VRT file.

    Then in FLOOD load the VRT as a Raster (select the file extension filter to All files (*,*) to be able to view it in the open file dialog. 

    Set the normal options the same way you would do for a Tif raster and press OK. You'll have control over the color scale. If this still does not work open the VRT in a file editor and delete the line that contains 

    <ColorInterp>[some information here]</ColorInterp>

    And reload the VRT file. 

    Hope this also helps. Kind regards;
    Luis

    Answer Verified By: Luis Souza