-------- Original Message --------
Subject:        Re: formats of map compression
Date:   Sun, 25 May 2008 11:41:26 +0100
From:   Nicholas Verge <[log in to unmask]>
To:     [log in to unmask]



Brian,

If you want a good application for compressing images to ecw/JPG2000, try
Manifold System GIS (around 300USD from manifold.net). Although a full GIS
and so probably more than you require, this has the ability to compress to
/decompress from such images without limits on the size of the
uncompressed image. I think ER Mapping has now imposed a 500Mb limit on
image compression using its freeware SDK and its freeware apps. Manifold
got its SDK before this limit came into being. Manifold very probably
provide the architecture to perform your image cataloging etc althoguh you
may need the more advanced versions for this which can seamlessly
interface with Microsoft, Oracle, IBM and other third party high-end
database technology. Again the cost is peanuts.




On Fri, 23 May 2008 16:55:21 +0100, Maps-L Moderator <[log in to unmask]> wrote:

> -------- Original Message --------
> Subject:        Re: formats of map compression
> Date:   Fri, 23 May 2008 08:40:28 -0700
> From:   Brian Bach <[log in to unmask]>
> To:     [log in to unmask]
>
>
>
> Nicholas and all,
>
> Thanks for the warnings regarding the Byzantine conditions surrounding
> Mr Sid use. I have praised their technology and quality in the past, but
> the roadblocks they throw up in the name of profit are ominous.
>
> I mention this because our library, (as well as the two-state
> consortium of which we are a partner) is experiencing an outrageous
> price-hike from the company that currently provides our catalog
> architecture. They are firm in their offer, so, our whole consortium is
> switching to OCLC. It's a considerable hassle, but in the long run we no
> longer have to be so vulnerable to the whims of the corporate mentality.
> By their rigidity, the company we use now loses a significant contract.
> How's that for good business practices?
>
> We in public sector libraries have to be very wary of these and other
> tactics, some of which border on extortion.
>
> Brian
>
>
>
> Brian P. Bach
> Documents/Maps
> Brooks Library
> Central Washington University
> 400 E. University Way
> Ellensburg, WA 98926-7548
> USA
> [log in to unmask]
> http://www.amazon.com/Calcuttas-Edifice-Buildings-Great-City/dp/8129104156
>
>
>>>> Angie Cope <[log in to unmask]> 5/22/2008 1:55 PM >>>
> -------- Original Message --------
> Subject:        Re: formats of map compression
> Date:   Thu, 22 May 2008 21:47:21 +0100
> From:   Nicholas Verge <[log in to unmask]>
> To:     [log in to unmask]
>
>
>
> Dear Linda,
>
> You asked:
>
> "What kind of formats have You used creating datafiles – MrSid or
> JPEG2000, or someone [something] else?"
>
> As a national librarian, i expect you are aiming to make your data
> easily
> accessable and usable by as many people as possible. Therefore,
> whatever
> format you use, please do not use MrSID or any other proprietry format
> for
> which there no efficient decompression algortithms publicly released
> and
> freely available. Contrary to what has been stated MrSID is not an
> industry standard format, although Lizardtech has tried every
> commercial
> and legal trick in order to present it as such in order to entrap the
> unwary into using its expensive software to compress to and decompress
> images from MrSID.
>
> Why you should not provide images in MrSID format:
>
> MrSID files can be viewed when in native compressed form by various
> applications. However, major problems arise when the images need to be
> used in a GIS environment or similar. Then, it may be necessary to
> decompress the MrSID image to a conventional image file format. This
> is
> usually done so that the image can be cropped to an area of interest,
> its
> contrast and colour adjusted or so that the projection of the image (if
> a
> geographical one) can be changed. All these can only be done to an
> image
> if it not encoded using wavelet-baed algorithms or if it is in such a
> file
> format, only once the image has been decompressed.
>
> To decompress MrSID images efficiently requires use of properietry
> technology owned by Lizardtech, for use of which this company demands
> high
> licensing fees. There are freeware decompression tools that can also
> be
> used for this, but Lizardtech has not released software development
> kits
> to allows third parties to produce efficient MrSID decompressors. As a
> result the freeware decompressors are hobbled and are very slow.
> Decompression of even relatively small files can take many hours.
> Large
> files can take days.
>
> Fortunately, you may achieve the same image compression, by using
> JPEG200
> or its predecessor ECW. Both of these formats ARE widely used in the
> GIS
> and remote sensing industry and the developer of JPEG2000, ER Mapping
> (now
> part of Leica) has released SDKs to third party software devlopers so
> that
> JPEG2000 files can be used and decompressed easily. They also released
> freeware to allow the same. Therefore, on behalf of the GIS and remote
> sensing community, if you wish to provide map scans and supply these in
> a
> format that uses wavelet-based compression technology, please only use
> JPEG200 or ECW.
>
> Also, regardless of the public domain technology i hope you will use,
> it
> is equally important that you scan the maps at sufficient high
> resolutio
> that the information shown on the map is legible and is not obscured
> by
> file compression. This is particulallry essential for small labels and
> closely spaced topographic contours. To ensure that these remain
> legible
> please scan at 400dpi or greater, and in 24-bit colour.
>
> Sincerely,
>
> Nicholas Verge
>
>
>
> On Wed, 21 May 2008 18:25:37 +0100, Maps-L Moderator <[log in to unmask]>
> wrote:
>
>> -------- Original Message --------
>> Subject:        formats of map compression
>> Date:   Wed, 21 May 2008 19:41:59 +0300
>> From:   Linda Akmentiņa <[log in to unmask]>
>> To:     <[log in to unmask]>
>>
>>
>>
>> Dear Colleagues!
>>
>>
>> The matter of my inquest is formats of map compression.
>>
>>
>> The Department of Cartographic Materials of National Library of
> Latvia
>> have started a Digital Map Project. What kind of formats have You
> used
>> creating datafiles – MrSid or JPEG2000, or someone else?
>>
>>
>> What are Your thoughts regarding this matter?
>>
>> Thank You for sharing Your experience,
>>
>>
>>
>> map librarian,
>>
>> Linda Akmentina.
>>
>
>
>
> --
> ----------------------------------------------------------------------
> Nicholas J. Verge BSc. FGS
> Geologist and geological remote sensing/GIS consultant
>
> CEO,
> Earthscience Technologies,
> Henley-on-Thames, Oxfordshire, UK.
>
> Voice: ++ 44 (0)1491 572022 (office hours 0900-2200UTC, Monday -
> Saturday)
> Email: [log in to unmask]
>



--
----------------------------------------------------------------------
Nicholas J. Verge BSc. FGS
Geologist and geological remote sensing/GIS consultant

CEO,
Earthscience Technologies,
Henley-on-Thames, Oxfordshire, UK.

Voice: ++ 44 (0)1491 572022 (office hours 0900-2200UTC, Monday - Saturday)
Email: [log in to unmask]