"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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