"Evans, James R Civ USAF ACC 84 RADES/SCZE"
<james.ev...@hill.af.mil> 11/06/2013 10:48 a.m. >>>
So, I'm guessing there's no easy way to automate this? Even
looking at the states, some of the states are in two zones, and
Texas is across 3 zones. At least the naming convention of the
files indicate the UTM zone. For instance:
m_2408002_ne_17_1_20100422_201001123.jp2, is in zone 17. As far as
I can tell, all the files in a particular directory are all in the
same UTM zone. I could create a layer for each UTM zone across
CONUS, but that's not going to be particularly useful to my users.
I'm thinking of making a layer for each state. For the stats that
cross zones, there will probably be two layers. For Texas, there
would be Texas_east, Texas_middle, and Texas_west. I will
probably limit visibility until zoomed in sufficiently to see the
whole state on the screen anyway, since the continental view of
this data is pretty crappy anyway. So now it seems like it will be
a lot of grunt work just copying these directories up to the
server, and going through and creating a shape file index for each
state. For states in more than one UTM, there would be more than
one shape. Then I'll have to add a layer for to my mapfile for
each shapefile, using the correct projection. Is there an easier
way? I'm starting with Oklahoma, which is also in three UTM zones.
I'll get that working before moving on. Any suggestions on making
this pretty would be welcomed. :-)
-----Original Message----- From: Stephen Woodbridge
[mailto:wood...@swoodbridge.com] Sent: Monday, June 10, 2013 12:34
PM To: Evans, James R Civ USAF ACC 84 RADES/SCZE Cc:
mapserver-users@lists.osgeo.org Subject: Re: [mapserver-users]
Best way to import 4.5TB of imagery?
On 6/10/2013 12:57 PM, Evans, James R Civ USAF ACC 84 RADES/SCZE
wrote:
Hi Stephen, Thanks, for the reply. I previously got 4 sample
images from the USDA, and was able to get them to work just
fine. There was no processing
required.
The sample images I got were all from Utah, and they are NAD83,
UTM zone
12.
I added the 4 sample images to a shape file using gdaltindex.
I used
UPSG
26912 and mapserver served them up very quickly for such large
files.
Now I have this entire data set, and it stretches from UTM zone
10, to UTM zone 19. The data is divided into directories by two
letter state abbreviations, and under that into subdirectories.
I'm just wondering how to add this to my mapfile. Do I need a
different entry for each UTM
Zone?
How is it possible to get a single layer entry that includes
multiple projections? This is looking like a huge job and I
just want to know the best strategy for getting this done.
So now you have a problem. You data is in UTM spread over 10
different projections. What do you plane to do when have your
image is zone 10 and half is in zone 11 or if you zoom out and you
images has 3-4 zones displayed?
All data in an image must be rendered in the same projection. While
I don't doubt that your test with 4 images worked fine, did you
you test this a multiple zoom levels and at some point you will
probably want to create a super overlay image so you do not have to
open multiple files to just pull a tiny overlay out of each one.
Your use cases will determine how you want to deal with the data.
For example does it HAVE to be in a UTM projection, or can you
work with a Spherical Mercator or geographic projection? The end
solution will be much easier if you can work with one common
projection over your whole data set. Otherwise, you will have to
deal with the transitions from one zone to the next or maybe set up
10 separate servers that only serve one zone.
Having pushed larges amounts (4-25TB) of imagery data more than
once it is important to make these decisions up front and and
prototype up something like a 4-10 degree square across a UTM
boundary and make sure that the results are going to be what you
expect before you process all the data.
-Steve
Thanks, James
-----Original Message----- From:
mapserver-users-boun...@lists.osgeo.org
[mailto:mapserver-users-boun...@lists.osgeo.org] On Behalf Of
Stephen Woodbridge Sent: Friday, June 07, 2013 8:41 AM To:
mapserver-users@lists.osgeo.org Subject: Re: [mapserver-users]
Best way to import 4.5TB of imagery?
On 6/7/2013 10:31 AM, James_in_Utah wrote:
Hi, We just got 3 hard drive, loaded with 4.5TB of NAIP
imagery for all of CONUS. I think there's a total of about
400,000 jpgs. The data is in directories, by states. Under
each state, there are subfolders, probably reference by
longitude. Other than going through folder by folder, adding
each image to a shape file using gdaltindex, what's the best
strategy for loading a couple of hundred thousand files up to
our server and making the imagery available via our mapserver?
Should I maintain the current directory structure when I copy
the imagery to the server, or just dump all of it into a single
directory? Do I want to stay with 1 shape file, or break it up
by state? We eventually want a contiguous layer for all of
CONUS to
be served up to our users.
James,
Since imagery data is served via gdal, you might want to also
ask this question on the gdal list.
There are issues with jpg related to the fact that if you only
want a small part of the image you still have to uncompress the
whole image. So part of the answer might be that you need to
pre-process all the imagery into something like a jpg compress
tiled geotif or something else.
You also need to consider what projection your imagery is in and
what projection you want to display it in. Because if you need
to preprocess the data, that would also be a good time to
reproject it.
Anyway the gdal list can probably ask additional questions to
help sort all that out.
-Steve W
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