Ask A Cartographer

Arrows pointing to compass direction in attribute of point feature

March 10 2008 | 1 comment
Categories: Cartographic Effects, Symbology

I am plotting permanent photo monitoring locations on an interactive map, and would like to symbolize the direction in which the photo was taken (as recorded in degrees in a "compass direction" field in the attribute table of a point feature class. How should I approach this?

Mapping Center Answer:

On the layer properties dialog's symbology tab, use the Advanced button and choose Rotation. This will ask for a rotation field that contains the angle that will be used to orient the marker symbol.

Late last year we wrote a blog entry on rotation angles that may help as well.

Worst case, you'll need to add a new field to your data and manually enter the angles. If you need to do that, set up the symbology in advance so you'll instantly see the result of your work; allowing you to fine tune it in a relatively interactive fashion.

One Step Further? posted by Paul Cook on Mar 19 2008 12:26PM
I don't know if this is so much a comment or a new question.

I have photograph taken in the field with a GPS enabled camera. Unfortunately the camera does not have a built in compass so I have to assign an angle as described here. I then use representations to show an arrow with its origin at the point collected pointing in the direction the photo was taken based on the value in the field.

All is fine up to this point. Now I have to label each point with the photo name/number. Currently I create the labels using Maplex. The problem being that there are minimum two photos taken at each location, sometimes four, upstream and downstream. This is why my arrows must be offset from the actual point. Then I turn the labels to annotation and have to manually place the annotation at the end of the corresponding arrow.

The question. Can I set the label to be located at a certain location around the point based on the same "rotation field". So each label would be offset from the point a certain amount, simple offset distance, and placed on the same compass heading as the arrow is pointed. This would really save me a lot of time.

TIA,

Paul

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |