[Geomoose-users] caching aerial photos in MapServer

[Eli Adam]

I just remembered that I am also assuming fcgi.

On Thu, Nov 3, 2016 at 11:49 AM, TC Haddad <tchaddad at gmail.com> wrote:
> Hi Tim,
>
> I get the idea you are looking for the big picture of how caching can fit
> into what you want to do. I agree with Dan that you should look into
> MapCache.
>
> Basically if you have MapCache set up in front of your MapServer, all
> requests past first through MapCache, which first checks if the request
> already exists in the cache, and if so, it shortcuts the process and never
> needs to talk to MapServer, as it can serve the tile directly from the
> cache. If an area has never been requested before, the request is
> transferred to MapServer, which does it's thing, and passes it's result back
> to MapCache for storage for future requests.  This model is a "cache on
> demand" situation, which is different than "cache in advance", where you
> might generate all the tiles possible in advance. Caching in advance is also
> possible, but usually requires a larger amount of disk space to be available
> than aching on demand does.
>
> From your MapServer map file perspective, Your map files are set up as you
> normally would. MapCache is an Apache module that must be enabled in Apache
> in order for you to use it. You configure it using a Configuration XML file
> where you point it at the MapServer services that you would like to cache.
>
> From your front end user perspective, all that is different is the base URL
> that you send them to for the cached services (MapCache base URL vs raw
> MapServer URL). So usage for the user is totally the same as non-cache
> usage. In my experience caching does improve performance, especially if your
> user interface is making tiled requests, rather than single image WMS
> requests.
>
> A few other advantages of using MapCache:
>
> - MapCache will allow requests of multiple tiling schemes from the same
> cache - e.g. TMS, Google Maps, WMTS
> - you can choose to cache an irregular subset of your imagery - for example
> a watershed basin - and save on the disk space of all the pixels outside of
> your basin
>
> I'm sure there are more, but these are the ones that I have found most
> handy.
>
> Tanya
>
>
>
> On Thu, Nov 3, 2016 at 8:58 AM, Eli Adam <eadam at co.lincoln.or.us> wrote:
>>
>> I've found that with well optimized tiffs (single YCBCR JPEG
>> compressed tiff in the correct projection with overviews), there is
>> essentially no time or processing spent accessing and producing aerial
>> views.  What time is spent delivering imagery to the client is usually
>> network transfer time which will be the same in cached and non-cached
>> cases.
>>
>> The command line tool, shp2img, can be used to give timing information
>> from your mapfile.
>>
>> Have you concluded that caching (i.e. file access and processing
>> times) would indeed speed up your application?
>>
>> MapServer or GDAL lists might be better for aerial imagery
>> optimization, serving, and caching discussions.  Searching the
>> archives on nabble might turn up past discussions too.
>>
>> Best regards, Eli
>>
>> On Thu, Nov 3, 2016 at 8:18 AM, Dan Little <theduckylittle at gmail.com>
>> wrote:
>> > Have you looked at mapcache? http://mapserver.org/mapcache/
>> >
>> > Brought to you by the good folks at MapServer.
>> >
>> > On Thu, Nov 3, 2016 at 9:50 AM, Tim Hennig <timhbellevue at gmail.com>
>> > wrote:
>> >> HI Everyone,
>> >>
>> >> I was wondering if someone can direct me to good information regarding
>> >> caching aerial photos in MapServer.  I know this is not a GeoMoose
>> >> question
>> >> pertaining to the application, but I would like to start researching
>> >> this
>> >> and possibly implement this sometime in the next month.
>> >>
>> >> I’ve looked at the MapServer website, but I’m trying to figure out the
>> >> process.  Can use ArcGIS cache tiles and tie it into MapServer?  Is
>> >> there an
>> >> add-on QGIS to cache? Etc.?
>> >>
>> >> I also thought about using REST services from the county that I reside
>> >> in,
>> >> but the caching is not as detailed at a municipal level.
>> >>
>> >> Right now the GeoMoose is using TIF images.
>> >>
>> >> Tim Hennig
>> >> Village of Bellevue
>> >>
>> >>
>> >>
>> >>
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