Ask A Cartographer

relative versus absolute location

May 23 2008 | 0 comments
Categories: Map Data

How can I display features with their absolute coordinates when they
were drawn in relative to the other features using an aerial as a backdrop?

Mapping Center Answer:

I'm not sure given the brevity of your description, but two things come to mind.  First would be if you actually have the absolute coordinates as attributes.  Just export the table (open the table window and click the Options button and then choose Export, which will just save the attributes [not the shapes] to a new table), and then create an XY-Layer (tools menu, then choose Add XY Data). 

That will work for points.  However if you've got line or polygon data (or don't have the absolution locations as attributes), you will need to have a control dataset.  If you're familiiar with the coverage data model, think of this as a set of tics. 

 If you're not familiar with coverages, then the control dataset is a set of known locations, e.g., benchmarks that you want to align your features against.  This control dataset is also what someone should have used to georeference and rectify the aerial photo before capturing the features you need to adjust.  That said, the tools you need to use are in the Spatial Adjustment toolset.  The online help for spatial adjustment is quite good, so start with the topic called An Overview of Spatial Adjustment. Be sure to review the related topics there as well.

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

Contact Us | Legal | Privacy |