You can do this by comparing the WGS84 coordinates shown on your GPSr against the coordinates at the top of this cache page which is the coordinates for one of the County Survey Control Points maintained and surveyed by the Thurston County GeoData Center.
These Survey Control Points are surveyed down to five decimal places in the Degrees, Minutes, Seconds format. I have converted those coordinates into the standard Degrees Minutes.DecimalMinutes format that all fellow cachers are so fond of. (Yipes. I ended a sentence with a preposition. My eighth grade English teacher would kill me!)
Thus; the particular Survey Control Point that you are looking for is a round brass disk in the cement sidewalk on/near a bridge I-5 overpass and is documented by the Thurston County GeoData Center as: (In Degress, Minutes andSeconds format)
| N |
47o |
02 |
25.70749 |
| W |
122o |
52 |
08.93087 |
This computes to our "normal" Degress Minutes.DecimalMinutes format of:
| N |
47o |
02.428 |
| W |
122o |
52.149 |
I thought that it would be kind of "fun" to follow your GPSr to a point which has a set of positively accurate known coordinates and compare that to what you are showing on your GPSr while standing on that point.
When you find this Survey Control Point, you will see that it has an "Identifier" on it which begins with "GP" and then is followed by five (5) numerics which we will call "ABCDE".
Therefore, the coordinates for the actual cache (small cache with logbook) are as follows:
| N |
47o |
02.X1X2X3 |
| W |
122o |
53.X4X5X6 |
where
X1 = A - 2
X2 = B + 3
X3 = C
X4 = D + 2
X5= E - 5
X6 = A + 2
So .... go find that Survey Control Point and compare the coordinates of that Survey Control Point (shown on the top of this cache page) with what your GPSr is telling you, obtain the five numerics on that round brass DOT disk, "Do the Math" (solve for X1 - X6) and then go find the cache!