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Delineating a Stream Network Based on NDWI Raster Values

Question asked by icemannn1989 on Oct 30, 2014
Latest reply on Nov 19, 2014 by icemannn1989

Ok, So this is my first post I have ever done on any forum ever. So follow me on this.....

 

I am working with high resolution Quickbird Satellite data with bands R,G,B, and IR. I am attempting to extract a stream network at the finest detail level the data will allow. My method right now is to spectrally resolve streams via band math. Overtone of the issue is that there is disconnection within the stream network and significant noise surrounding streams. Continue reading if interested with my problem.

 

Step 1).     I am using the raster calculator (Spatial Analyst --> Map Algebra) and am creating an output with the equation (float(Blue Band) - float(Red Band)) / (float(Blue Band) + float(Red Band)). The output is a NDWI raster. Streams are in this raster and I want to extract them.

 

Step 2). Reclassify the image into 3 classes based on Natural Jenks method. (Spatial Analyst --> Reclass --> Reclassify). I now have a "Deep water" or "Lakes" classification and a "streams" classification.

 

Step 3). I then Extract by Attribute (Spatial Analyst --> Extraction ) for both the "Deep Water" and "Streams" classes from the reclassification in order to have a separate raster with the spatial extent for both  "Deep Water" and "Streams" classes.

 

Step 4). I then Extract by Mask (Spatial Analyst --> Extraction) using the new individual reclass rasters for "Deep Water" and "Streams" as the masks to extract the actual NDWI pixel values within the spatial extent of the "Deep Water" and "Streams" classes.

 

Ste 5). Convert NDWI raster pixels to shapefile point data. (Conversion --> From Raster --> Raster to Point)

 

What do I do from here? I do not know how to connect the points or the raster images. I want a stream network but there are breaks all over the network. I have tried many different features and tools and cant seem to get the correct one. Buffer, aggregate, filter, etc. I am looking for a way to do this completely in Arc.

 

Pictures attached.

 

Thank you for your time.

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