[Geomoose-users] Estimating tile size

[Brent Fraser]

Paul,

Doing the math on your TIFF air photo, I get:

40 sq mi X (63360 inches per mi  / 6 inches per pixel )**2 = 
4,460,5440,000 pixels
     and so:
4,460,5440,000 pixels X 3 bytes per pixel = 12.46 Gbytes

So 800 sq mi would be 250 Gbytes

After tiling, I expect it would be 250 to 500 Gbytes.  You could try 
gdal2tiles.py on a subset of the air photo mosaic to get a better idea...

Best Regards,
Brent Fraser

On 1/29/2013 10:27 AM, Paul Wickman wrote:
> Yes, bytes.  Zowie...   I have a TIFF of an air photo for one of our 
> other municipalities (also 6-inch resolution), which is 20 GB 
> (uncompress).  That coverage is only ~40 square miles.  So, for a 
> single ~800 square mile county also at 6-inch resolution I'd 
> potentially be looking at 400 GB for the uncompressed source or... 
>  somewhere on the order of ~800 GB tiled?  Does that sound right?
>
> Anybody from MnGeo on this list with any input?
>
>
> On Tue, Jan 29, 2013 at 11:15 AM, Brent Fraser 
> <bfraser at geoanalytic.com <mailto:bfraser at geoanalytic.com>> wrote:
>
>     Do you mean how many bytes?
>
>     Looking at my Landsat tile pyramids (levels 4 to 12), they're
>     about the same number of bytes (hmm, I expected them to be double...)
>
>     But my source images:
>         - no compression on existing files (tiffs, e.g not jpeg)
>         - 3 band (color) imagery
>
>     The resulting tiles:
>         - compressed PNGs
>         - four bands (one alpha channel for transparency)
>
>     So  my guess is somewhere between "same size" to "double the
>     number of bytes" (unless the source imagery is compressed, then it
>     will be 5 to 10 times larger)
>
>     Best Regards,
>     Brent Fraser
>
>     On 1/28/2013 5:53 PM, Paul Wickman wrote:
>>     Greetings,
>>
>>     I know this type of question goes around often in various
>>     flavors.  Difficult to estimate exact size of rendered tiles, but
>>     thought I'd try to get some opinions.
>>
>>     I see this questions asked in a variety of ways and I know it's
>>     not exactly precise on how to get the answer, but I'll throw my
>>     question out to see what I get ;)
>>
>>     We have a client who would like us to tile and serve up
>>     high-resolution aerial photography that they own. The area is
>>     about 800 square miles and the imagery is 6-inch resolution.
>>     They'd like to be able to view the imagery at zoom levels 11
>>     through 20 (with level 20 being 1 pixel=6 inches). Is there any
>>     way at all to determine how large a resulting raster tile set
>>     might be?
>>
>>     Many thanks,
>>       Paul
>>
>>     -- 
>>     Paul Wickman
>>     CTO | Flat Rock Geographics
>>     612.280.5850 <tel:612.280.5850> | paul at flatrockgeo.com
>>     <mailto:paul at flatrockgeo.com>
>>     www.flatrockgeo.com <http://www.flatrockgeo.com> |
>>     twitter.com/flatrockgeo <http://twitter.com/flatrockgeo>
>>
>>
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>
>
>
> -- 
> Paul Wickman
> CTO | Flat Rock Geographics
> 612.280.5850 | paul at flatrockgeo.com <mailto:paul at flatrockgeo.com>
> www.flatrockgeo.com <http://www.flatrockgeo.com> | 
> twitter.com/flatrockgeo <http://twitter.com/flatrockgeo>

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