Step 1:  Select a line by pointing at the desired line until it is highlighted in black.  Or select a polygon by placing the tip of the mouse pointer within the desired polygon.  Or do both simultaneously.  (Note that highlighting the edge of a polygon doesn't select the polygon unless the tip of the pointer is actually inside.)
 
 

Step 2: With right mouse button choose What's This.
 
 

Momentarily, the What's This pop-up will appear, providing a Line Description and a Polygon Description.
 
 
 

The Line Description box shows the following fields:

Theme	Theme with which the line is associated
Length	Length of line in your chosen units
Entity	Numeric entity label for the line followed by a brief description of that label (usually the first sentence of the definition from the Master Data Dictionary)
Vertical Relation	Indicates if line is an underpass or overpass.  (Field isn't otherwise shown.)
Route(s)	Identification of numbered highways (for Roads & Trails theme only)

The Polygon Description box shows the following fields:

Theme	Theme with which the polygon is associated
Area	Area of polygon in your chosen units
Entity	Numeric entity label for the polygon followed by a brief description of that label (usually the first sentence of the definition from the Master Data Dictionary)
Agency(s)	Federal agency which administers the land (for Boundaries theme only)

Below the description boxes are a couple of preferences buttons.

Clicking the Show IDs button will bring up additional fields.  Generally these fields are only of interest to someone who needs to know the nuts and bolts of where the data is coming from.

The Show IDs button is a toggle:  if you turn it on, it will remain on for the remainder of your xviewsdts session, or until you turn it off.
 
 
 
 

Additional fields shown when Show IDs button is on:

CATD	The pathname of the CATD (catalog) file for the transfer that contains the line or polygon
Module	Name of the module within the transfer which contains the line or polygon
RCID	The record identity within the module of the line or polygon
ATID	The record identity within the primary attribute module which is associated with the line or polygon
SNID	The record identity within the node module for the pointnode at the start of the line
ENID	The record identity within the node module for the pointnode at the end of the line

 

Clicking the Show GNIS button will bring up another field in the polygon description box: GNIS name(s)

The Show GNIS button is a toggle:  if you turn it on, it will remain on for the remainder of your xviewsdts session, or until you turn it off.
 
 
 

The GNIS database is not part of the SDTS transfer.  Therefore there is no direct linkage between the SDTS data and the GNIS data.  Consequently, the names provided are really educated guesses at the true name.  For this reason the Show GNIS button is off by default.  You may choose to turn it on as an aid in identifying polygons, but you should understand that it is only an aid, not an authority.

Within the GNIS name(s) field are the following subfields:

Most probable name(s) - - -

Listed below the Most probable names(s) subfield are the names of nearby entity features, one of which may be the name associated with the selected polygon.  To the left of each name is a number which may be used to compare the relative distances from the polygon to the various GNIS names.  Although the 'm' following the number does signify meters (independent of your chosen units of measure), you should use these numbers for comparison purposes only: while the value should be fairly accurate for UTM projections, it is a only a very rough approximation for GEO projections.

Other names nearby - - -

To be listed under Most probable name(s), the GNIS name must be located either within the polygon or within a margin of a certain width around the polygon.  The actual width varies with the projection and the scale of the source map (i.e., map series).  GNIS names listed under Other names nearby are in the area just beyond that margin, but within a distance of four times its width.

There is a special case for reservoirs.  If the polygon is identified as a reservoir by the SDTS data, it must also be identified as a reservoir by the GNIS data to be listed under Most probable names; bodies of water which are not considered reservoirs by GNIS will be listed under Other names nearby.  You may sometimes find quite a long list of lakes and/or ponds which are "0 m" from the polygon.  If you think about it for a moment you will realize that these are places that now live beneath the surface of the reservoir.
 
 

Note that you may copy any or all text from the Line Description and Polygon Description boxes by selecting it with the left mouse button, then moving to your other application and pasting it with the middle mouse button.

Copyright © 2002 by Dapper Mapper