Additional Steps for Egeo450 students PRIOR to attempting to GeoReference their vector data using the
Spatial Adjustment Tools in ArcGIS...


Back to the   GIS Tutorials & Help Page...                         Back to the   SAL Home Page...


See also the main Spatial Adjustment tutorialpage


Before you can ‘Adjust’ (GeoReference) your Vector data you will need to Copy your three Feature Classes (the one’s derived from Coverages) to your new SPCN_NAD27 Feature Dataset in your Geodatabase. This step serves two purposes:

  1. It preserves your ‘Raw’ data in the un-adjusted ‘board’ coordinates (since Spatial Adjustment is an editing process as opposed to the creation of a new data layer - you don't want to edit your only 'raw' copy)
  2. Your new Feature Dataset has a specified X-Y spatial extent (or domain) with appropriate min/max values allowed for adjusted data. Without this being properly set, you probably wouldn’t be able to perform an adjustment…


          For the moment, these new Feature Classes will be falsely stored in a projected Feature Dataset (even though they still have raw coordinates). However, they need to be in their proper Feature Dataset so that we can edit (adjust) them, ending up with real-world coordinates and the features in their proper location…


The Process: 


Import your three vector Feature Classes from your Raw_Data Feature Dataset to your SPCN_NAD27 Feature Dataset. For this task, you can use ArcCatalog (Import / Feature Class (single)) or ArcToolbox (the Feature Class To Feature Class tool). In either case, even though you want to import multiple Feature Classes (your points, lines and polygons) you will need to use the single tool option since we are importing into a Feature Dataset as opposed to directly into a GeoDatabase. To do this:

o      For your Input Features, browse to one of your vector Feature Classes (points, lines or polys)

o      For your Output Location, use your SPCN_NAD27 Feature Dataset

o      For your Output Feature Class Name, enter an appropriate name (e.g., GEN_pts_SP27 or adj_gen_points or cov_pts_spcn27…)

o      Accept the other defaults and click OK

o      Repeat this process for each of your points, lines and polygon Feature Classes



You should now have two Feature Datasets (Raw_Data and SPCN_NAD27), each containing the exact same vector Feature Classes


Proceed with the Spatial Adjustment steps as outlined online ( ) using your new vector data (in your SPCN_NAD27 Feature Dataset) and your NAD27 GPS data. You should have corresponding features in each of these datasets.


For our purposes, you should strive for a RMS threshold of less than a foot or two (for both the individual links error and the combined RMS of the entire links file).



Thus your Geodatabase at this point should have your revised XY-Event Table, and two Feature Datasets, each with multiple Feature Classes (a total of at least 10).




Back to the   GIS Tutorials & Help Page...                         Back to the   SAL Home Page...