GEOG 566






         Advanced spatial statistics and GIScience

May 24, 2017

Manipulating Layer Properties in ArcGIS ArcMap 10.4.1

Filed under: Tutorial 2 2017 @ 1:09 am

Reva Gillman

Tutorial 2                                Manipulating Layer Properties in ArcGIS ArcMap 10.4.1

  1. Question that I asked:

What are the geographic distributions of some of the ‘riskier’ species that arrived on Japanese Tsunami Marine Debris (JTMD)? What do their native and non-native ranges look like, and how do they compare with each other?

First of all, I had to choose 4 species with clear invasion history out of the 104 JTMD species, to focus on. Out of the 31 with invasion history, I chose Asterias amurensis (seastar) and Hemigrapsus sanguineus (Japanese shore crab) since they are known to be an issue in other regions. I then chose two species with large non-native spread: Crassostrea gigas (Japanese oyster), an economically important aquaculture species, and Teredo navalis, the shipworm with an almost global distribution that has burrowed in wooden ships all over the globe for 100’s of years.

  1. Name of the tool or approach that I used:

Manipulating Layer Properties in ArcGIS ArcMap 10.4.1 in order to manipulate the polygons in the shape file, to make them appear different colors according to which realms were documented as native or non-native regions for each species.

  1. Brief description of steps I followed to complete the analysis:

First I made an excel spreadsheet of the species data, by going through each ‘risky’ species distribution, converting regions to realms, and typing that up in the spreadsheet. Then, I did a join with Realm_Code which matched up with the attribute table from the shape file. However, I ran into issues with mapping this data, as it would only map the region that was native, or non-native, without the other regions represented at all, so I had to figure out another method.

My second attempt was to directly select regions of the shape file, and change the symbology by going into selection, and clicking on use with this symbol. This may have eventually worked, but was very hard to figure out which regions to select for each species, and there was not an intuitive way to save the selections as a new layer.

Finally, I found out how to go into Layer Properties, and manipulate the shape file from there:

a. First you left-click on the layer you want to manipulate, and select Properties from the bottom of the options.

b. Go into Symbology

c. Underneath the Categories options on the left, select unique values

d. From the value field, select the field that you are interested in, in my case that was Realm_Code

e. Select the Add all values button on the bottom, which will put all of the selected field options in the screen.

f. From there, you can select a field, and remove it, or add values as needed, which I did for each species

g. By double clicking on each field, you can select the appropriate color that you want to represent each category, you can change the outline of the symbol, the fill color, and texture. I did this to make the color of invasive realms one color, and native realms another color, and regions where the species was both native and non-native another color/texture.

h. Then, you can copy and paste the layer, to manipulate again for the species, so you don’t have to start from scratch.

Layerproperties

4. Brief description of results you obtained.

Below, there are the 4 maps of each species distribution, to see the extent of their ranges.

 

Teredo navalis geographic distribution

 

 

hemi

 

 

Hemigrapsus sanguineus geographic distribution

Crassostrea gigas  Geographic Distribution

 

For clearer viewing of the above graphs, please download: Tutorial2

5. Critique of the method – what was useful, what was not?

This method can be tedious if you want to look at many different layers of maps. For me, it worked out because I chose to look at four different layers of species geographic distributions, but if this method was less tedious I might have looked at more. By going through and manually selecting each polygon, or realm, that I wanted to highlight, I had a lot of control over what the final map looked like, and I liked the level of detail you can find with symbology, outlines of polygons, fill color, and texture of fill. The final maps are straightforward, and easy to save each layer, copy, and paste the next layer so you don’t have to start from scratch each time.

Print Friendly, PDF & Email


No Comments

No comments yet.

RSS feed for comments on this post.

Sorry, the comment form is closed at this time.

© 2019 GEOG 566   Powered by WordPress MU    Hosted by blogs.oregonstate.edu