Ask A Cartographer

Generating and symbolizing current vectors

February 02 2012 | 0 comments
Categories: Symbology

I am working with ocean current data that have been symbolized as polyline vectors sized by magnitude and angled by direction attributes. I have two questions.

  1. How are lines (current vectors) developed from x and y rasters so that the resulting line is representative of the direction and magnitude of the originating rasters? I could not find clues in the toolset used to develop this dataset. (Marine Geospatial Ecology Tools, MGET)
  2. When applying arrowheads to the lines to indicate direction, smaller lines below some threshold are not capped by the arrows and just remain lines. How do I override this?

Utlimately I would like to have a polyline file of current vectors oriented in the correct angle, but have all lines be the same size, so smaller currents are not lost. I would like to color the resulting vectors based on the magnitude.

Mapping Center Answer:

You would have to contact the authors of the tools to ask about their procedures for converting the raster data to vector.  One the data are vectors, you can modify the symbology for lines in ArcMap. Double click the symbol you want to edit in the table of contents, click Edit Symbol and on the Line Properties tab of the Symbol Property Editor, modify the arrowhead for the line decoration.

To vary the color of the lines based on magnitude, use the Quantities > Graduated Color renderer on the Symbology tab of the Layer Properties dialog.

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

Contact Us | Legal | Privacy |