I have hydrographic data in the form of an xyz file. I would like to display it in ArcMap. I need to symbolize the points based on their depth, shallow points one colour and deep points another. With a small subset of data I was able to import the symbols, symbolize based on elevation and turn on labels at an appropriate scale.

xyz sample points

I then tried creating a multi-point file with the full dataset and set the symbology the same however I end up with unnatural bands.

xyz multi point

Is there a way to get the multi-point file to display the same symbology as the sample set? I want the user to be able to quickly zoom in and out of the data to be able to check the depth of any given point.

  • 3
    create a layer file and use that - then attach the data to the layer file - resources.arcgis.com/en/help/main/10.1/index.html#//… – Mapperz Jan 23 '13 at 16:02
  • Thanks for the suggestion but that tool won't work if the geometry is different (Point to Multi-point). I tried just adding the layer file and changing the source file to the multi-point but I still get unnatural looking rows, each point in the row has the same elevation information. – Sarah Jan 23 '13 at 17:27
  • 1
    Then you need to expand your "sample set" to include all values. – Mapperz Jan 23 '13 at 18:32

No, there is no way to get the multi-point file to display the same symbology (colors and labels) as the sample set.

One multi-point object has several locations (=points) but only one record in the attribute tabe. So all points which form together one multi-point have only one record in the attribute table and only one value in the field witch stores the elevation value.

Each point of one multi-point has its own x, y and z value. But as far as I know, you can not use the z value for display and label.

Maybe this is an alternative: use your points to interpolate a raster surface (with Spatial Analyst). If you show a large area the raster surface will display faster than a lot of points.

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use GMT (generic mapping tools):

1. This gives the range (ie. longitude, latitude, depth) of yourfile.xyz
minmax yourfile.xyz
2. Make the color palette to plot your points
makecpt yourfile.xyz -Cseis -T"here goes your depth range" > mycpt
3. Plot your points with color based on the depth
psxy yourfile.xyz -R"min longitude"/"max longitude"/"min latitude"/"max latitude" -Jm10 -Cmycpt -Sc.5 -B1 > ps
4. Convert the postscript (ps) file to PDF and PNG
ps2raster -A -Tf ps
ps2raster -A -Tg ps

After installed the GMT, simply writing in your console (Linux or Cygwin) or windows (cmd) for instance:

man psxy

Will give the details of that tool.

More simpler, use hypack or fledermaus to plot the depths with color, that's more easier, just a few clicks and voila. The problem is that those are not free and GMT is free.

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