[ka-Map-users] Highly Interested Developer with some questions

[Jacob Delfos]

Clark / Pete,

Regarding the use of aerial photography and PNG24: I noticed that Paul has integrated the changes (png transparency hack) into Ka-Map that allows PNG24 to be transparent in IE, along with changes allowing different image formats for different groups (by specifying an "imageformat" parameter in the metadata). So that is not a limitation anymore to the use of aerial photography. I successfully use jpeg format for full-colour imagery, and gif for our transparent vector layers.

Paul did mention about having issues with the png transparency hack for 8 bit PNG images (which Mapserver appears to revert to for vector data, even if PNG24 is the specified image format). But you could now instead use gif for transparent layers, while using jpeg for non-transparent layers, retaining the ability for full-colour images. Gif transparency works in all browsers without problems, providing GIF is specified as default outputformat in the mapfile (otherwise php_mapscript appears to produce non-transparent gif images). I did some testing, which showed GIF appears to compress indexed-colour images a fair bit better than PNG8 too (lossless). For the JPEG layers, you can pick the desired compression, and significantly reduce image sizes that way, somewhat reducing the speed problems that Pete mentioned. 

regards,

Jacob





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From: ka-map-users-bounces at lists.maptools.org [mailto:ka-map-users-bounces at lists.maptools.org] On Behalf Of Peter Giencke
Sent: 14 September 2005 03:54
To: cendrizzi at gmail.com; ka-map-users at lists.maptools.org
Subject: RE: [ka-Map-users] Highly Interested Developer with some questions


Clark,

1) Yes you can; we've been using raster [wms] backdrops extensively in many of our ka-map implementations. I've found however, that speed can suffer (from mildly to greatly) depending on the number and complexity of rasters used (duh). Also, best results are obtained when using PNG24 for this, but you'll have to 'hack' ka-map to enable PNG transparency, so that 'layering' works in IE.  (There's a thread for that here: http://lists.maptools.org/pipermail/ka-map-users/2005-August/000235.html). If these two concerns can be leveraged, the results are very nice (I have an example of this here: http://mds.glc.org/kamap_cvs3/).

2. Assuming you take the time to peruse the api's source code and consult the mailing-list archives, you should be able to get up and running within a weekend, or week, depending... Although ka-map is a relatively new creation, it's still very functional at this early stage.

-pete


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From: ka-map-users-bounces at lists.maptools.org [mailto:ka-map-users-bounces at lists.maptools.org] On Behalf Of Clark Endrizzi
Sent: Tuesday, September 13, 2005 2:17 PM
To: ka-map-users at lists.maptools.org
Subject: [ka-Map-users] Highly Interested Developer with some questions


I run a development group that is developing a real estate application.(web based).  It's PHP and from the start we have had the idea of including mapping software to integrate with mapping stuff.  We've looked at multiple web based mapping vendors, including Arc IMS, but haven't found something that we consider a good solution.  We want something that is easy to use like Google maps but also very flexible.  Furthermore it's important that we have the ability to include it in our mostly closed source applicaton.  

I'm not really a mapping guru as most of my incomplete knowledge comes from a mapping group in the same building so I have some basic questions about whether we can use ka-map and contribute to it as well.  
1.  Can you use aerial photography with ka-map?  We use aerials provided by air photo USA and want to use that on our web based stuff.  I'm guessing right now only street maps are supported.  With aerials, we need to use these images (they come in jpeg) and associate their world files (which have the projection ifnormation in them).  Is this something that could be done with this software (if it doesn't exist now could it be realistically added?).

2.  Could we expect to use this stuff by the end of the year?  Based off the examples it looks like ka-map is pretty far along...

Actually that's probably all the questions for now since our use of ka-maps is contigent on them.  Currently we have four developers including myself with pretty extensive experience in web development, javascript (including just starting to get into "ajax" stuff).  I hope it's clear that we're not trying to selfishly use and expect ka-maps to work for us as we're willing to improve it to meet our needs if it doesn't have the functionality.  

I hope this can work out since you have done excellent work!  

Thanks,
-- 
-Clark Endrizzi

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