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I'm using ArcMap 10. I want to display the area of simulated avalanches. I want this area to be divided in different colors depending on the thickness of the deposit. I managed to do that. But I want all the simulated avalanches to refer to the same scale and same legend of thickness. This means that for every simulation a certain range of values of thickness (e.g. from 2m to 4m) falls within the same color. The problem is I need to transform my raster into polygons (for future calculations of area ratios) and to do this it must be integer. So I guess I have two choices: "raster calculator" or "reclassify". With "raster calculator" I see I obtain my integer raster with the number of classes of thickness I want but the areas are changed a bit (I don't know why). With "Reclassify" I obtain an integer raster where my areas are essentially the same as before, but it can have a number of classes not higher than the value of thickness it reaches. In other words using the "reclassify" tool I would have each simulated avalanche with its own scale of thickness and not a common thickness for all my simulations. Is there a way to accomplish what I'm looking for? I hope I explained it clear enough (It's a bit hard to explain this even in my own language).

Thank you,

Michele

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1 Answer

up vote 2 down vote accepted

For your collection of avalanche simulations,

  1. Find the minimum and maximum values. Use the Cell Statistics tool to accomplish this.
  2. Build a Remap table using the min/max values from step 1. Format it as described in the help section of the Reclassify by Table tool.
  3. Use the Reclassify by Table tool to reclassify your simulation results to a common scale(as defined in the remap table). Set the missing_values parameter to NODATA
  4. Convert reclassed rasters to polygon
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there's a step I can't overcome. How to create a remap table. I created one (with excel) with "from" values, "to" values and "output" values, but when I try the reclass by table tool I can select the "from" and "to" fields but there's no selectable choice for the "output" field although I created it. What am I doing wrong? I did read that any text file is good to create the remap table, but how would I import it in arcmap? That's why I created the excel table. –  Michele Cordini Aug 13 '13 at 17:33
    
I found an alternative solution, though it might be more time consuming. I will just reclassify my simulation rasters, the raster-to-polygon them and then I would add the missing values as polygons (without drawing them). As I go in properties to classify them to the same number of classes I manage to give them the same scale. –  Michele Cordini Aug 13 '13 at 17:47
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