Latest Contributions by AshBarnes

‎05-03-2018

I have used an analysis mask so the area should theoretically not change regardless? yes i do have a before and after rasters (DTMs). the attribute table will give the VOLUME i.e. the net gain or loss per pixel, so could be -/+ any value. However, after overlaying a fishnet and therefore creating a gridded zone, then using zonal stats you don't get a VOLUME, you get SUM, MEAN, RANGE etc. Hence thee are no negative values, which does not seem correct!

‎05-03-2018

Thanks for the reply, not sure cell statistics gives me much different to the zonal statistics as a table (although i may be misinterpreting the output). I was more interested in finding a way to condense data down to a more manageable level from the 'CutFill' analysis table?

‎05-02-2018

Hello all, I have several DTMs for which i would like to calculate the change in volume over time. For this I have used the 'CutFill' tool which has generated useful per pixel (2x2m) results in the attribute table. However there is over 13,000 pixels which is far too much data to manage, so I have used a fishnet and then zonal statistics as a table to attempt to calculate volume change per zone. However this hasn't produced a volume as i expected , i only have SUM and MEAN, which I'm unsure of the meaning of? Is there another way maybe using the attribute table of the 'CutFill' or zonal statistics to condense the data to a more manageable size? Hope this makes sense. Thanks!

‎03-26-2018

I do have multiple dates (nearly every year between 2001 and 2017). For this i used the 'Minus' to calculate the difference for each year i.e. 2001-2002, 2002-2003, 2003-2004 etc. I've created a polygon around my study area so hopefully the zonal statistics should work if applied for each year, thanks! I expected that using point cloud could be more useful for finding the volume in a 3D environment, do you have any idea? Thanks again!

‎03-26-2018

Hi Everyone, I am currently undertaking a project attempting to explore how morphology along the Holderness Coast, England, has changed over time. I have LiDAR tile data from 2001 - 2017 all at 2m spatial resolution (DTM and DSM) and LiDAR point cloud data from 2008 - 2017. I have tried to use surface creation tools such as 'Slope' and 'Cut-Fill' etc but have not had great results. Ideally I would like to quantify the change in sediment volume over the time but not sure what is the best way to go? Currently I have created a fishnet that overlays LIDAR data set, then calculated the change height for each zone in the grid but i feel there is a more sophisticated analysis which I could undertake? Thanks!

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Latest Contributions by AshBarnes

Re: How can I derive volume from zonal statistics?

Re: How can I derive volume from zonal statistics?

How can I derive volume from zonal statistics?

Re: How can I quantify volume change from multi temporal LiDAR data in ArcGIS?

How can I quantify volume change from multi temporal LiDAR data in ArcGIS?