[pct-l] Google Earth

enyapjr at comcast.net enyapjr at comcast.net
Thu Jun 21 09:03:48 CDT 2012


>> When I look at the PCT on Google Earth, how current  are the images? Is 
>> there an easy way to determine how old they are?  
>>  
>> Just wondering.
>>  
>> Thanks for your answers.
>>  
>> The Old  RidgeRunner

>From Craig/SunWalker:
> You should be able to see a copyright notice near the bottom of the Google Earth window...


FWIW, a little extra FYI...

The 'copyright' noted by SunWalker does not have much to do with the date an individual 'image' was photographed...

Until zoomed in quite a bit, GE is a 'mosaic' of many individual images from varying altitudes depending upon the original intended usage of those image sets - and thus the individual image dates can vary by many years due to whatever 'project' initially required the images...

If one looks immediately below said copyright info there is an opaque 'location bar' at the bottom of the GE window - on the right side of that bar it shows the "Eye alt" (altitude) of the view, in the center is the latitude/longitude coordinates and surface elevation of the cursor (the 'hand')... ...as one zooms in on the image, the formerly blank left side of that 'location bar' eventually shows an imagery date plus the 'history' icon...  Sometimes that image date will change as you move the hand cursor around in the screen image (zoom in on the PCT at the Mexican border, you will notice a differing color 'cast' one side of the image to the other - to the left side of the image the date is 2/29/2008, while on the right side it is 6/6/2011; seems that areas of 'interest' to various agencies are the most recent imagery updates - such as the Station Fire in which most images in that area are as recent as 12/3/2011)...  What are some of the possible 'best' uses of that 'history' utility? - if you have downloaded a PCT trace and follow the trail but it winds up under cloud cover, use an earlier image by going back in the image history to where there is no cloud cover...  Sometimes it is also interesting to compare development in some areas - 'see' the encroachment of housing, wind farms, logging, etc. along the trail corridor going back to 1993/94...

Hope all that rambling helps!

Happy trails!!!
Jim (PITA)



More information about the Pct-L mailing list