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What symbology will show the presence of multiple types and quantities at the same location?

December 11 2007 | 1 comment
Categories: Cartographic Design, Cartographic Effects, Data Modeling, Map Data, Symbology

I have been asked to produce a map that shows marine sampling locations of various coral types. There are 5 coral species represented. Additionally, the markers are to differ in size depending on the presence/quantity of coral found at that location. The problem I am having is some sampling locations have multiple corals present and multiple quantities present. Some sample sites are being cover-up by other sites and visually, data is being lost. I have attached a JPEG file to show what I have done so far but it's still lacking and doesn't seem to be accurately depicting the data. The data is also tied to a bathymetric layer.
Thanks for your help!

Attachment: Presence/quantity of corals

Mapping Center Answer:

Given your problem: show type, quantity and location of samples; I’ll first say there’s nothing in ArcMap that will do all three automatically. You can do type and quantity (using the bivariate symbology) or you could offset automatically, but not have the symbology you need. Also, given that it doesn’t look like you have too many sample sites, I would recommend the following:

1. Add two additional feature classes:

a. A point feature class to represent the sample sites. Symbolize with an X or something similar. I would also have a unique ID for each site, that way you can add that to your sample’s as an attribute and use as the basis for a relationship, if you need an interactive component for your map.
b. A line feature class to store leader lines

2. Then edit your samples, moving them slightly away from the sites, and then add leader lines that connect the sites.

3. Symbolize the samples using the bivariate symbology.

The result should look a bit more like an information-graphic or an illustration instead of just drawing your data on the screen.

What symbology will show the presence of multiple posted by Christopher Caird on May 2 2008 12:34PM
Background:
I had a similar problem with a twist.
I had worked for many months with our Planning Department to designed and develop a "LandUse" data set. Within the attribute table were two significant fields. 1) LU_Catagory_Existing 2) LU_Type_existing.
We have 5 different Land Use Catagories and 25 different Land Use Types.
Staff requested seeing a map that showed Each Catagory and the Land Use Types within that Catagory.
Keep in mind all this information is contained in one data set.

Solution:
Add the "LandUse" 5 times to the map project (because there are 5 Catagories). Open up the 1st "LandUse" and go to Properties>Defination Query. Perform a defination query using the first Catagory (in this case RESIDENTIAL).
Now only those polygons representing the RESIDENTIAL catogory are shown (in one color). Open the Properties>Symbology and chose Catagories and Pick "LU_TYPE_Existing" and add all values. Next choose a color ramp that is all one color type but different shades.

Now I repeated this step for the other four "LandUse" layers. I only change the defination query to the specific catgory and then change the color ramps.

If this is confusing just give me call or drop me an email
Chris
843-341-4794
chrisc@hiltonheadislandsc.gov

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