Yo McFly…..

Posted on Wednesday 22 April 2009

biffI enjoyed reading this post from Paul, you can always rely on a good comment trail when ‘ESRI’ appears in one of his post headings….however comparing ESRI to crack dealers, as one of the commentors states is IMO taking things a tad too far. 

It reminded me a while back I was lamenting about AXL, which i received some grief about:

“why would you want to go back to all that dirty XML editing when you can just set up a map document and publish it?” someone asked…

“exactly… you need to be able create a map document” I answered…..and this (i think) is one of the points Paul is making.

Indeed recently we had a client who had isolated tiers in their architecture with desktop ArcGIS  software unable to access the same database as the server ArcGIS software, which makes for a tricky implementation when you don’t have ArcGIS desktop on the ArcGIS Server machine, (because its a Linux box). Anyway with an ‘open’ format like AXL this would have been a little bit easier to implement. We managed.

Anyway Paul is missing out on some of the facts, true ESRI uses the binary MXD format to underpin services within ArcGIS Server, but they are also adding support for the MSD format. MSD is basically a zip package which contains a documentInfo.xml file (document metadata) and a folder containing more XML files (usually a layers.xml and individual xml files describing each layer). This sound familiar? Not going into too much detail, but basically the layers.xml contains all the usual stuff, spatial reference, transformations, bookmarks, layer definitions, scale thresholds blah blah blah.  Each individual layer contains a definition of the features contained in the layer together with symbology information etc. Apparently MSD will remove a performance bottleneck in traditional ArcGIS Server MXD based services.

The aim of this post it not to open up the usual ESRI v’s Open Source  -  ’my dad is stronger than your dad’… kind of thing, I just wanted to decorate the dicussion with some extra information. Now I’m off to smoke some crack……

2 Comments for 'Yo McFly…..'

  1.  
    April 24, 2009 | 11:19 am
     

    The MSD document you linked to describes adding attributes to DXF & DWG files, but nothing to do with XML… ?

  2.  
    mapbutcher
    April 24, 2009 | 11:37 am
     

    Rob, clearly I’ve got my MSD’s mixed up. There’s just so many MSD formats around these days, I remember the days when it was just the good old one and only ‘.msd’ , why did someone have to go and ruin things?

    Its odd to think that they bear no relation, they both provide a syntax for layer descriptions etc?

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