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State of bezi?r curves and GIS

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#1
frax

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I was just thinking this morning -- what is the state of GIS and bezi?r curves? I know that ArcGIS GeoDatabases support them, but that is as far as I know, how about other software? (I am embedded in ESRI-land...) And for GDB, btw, I think few people are using this functionality so far - I have actually very limited experiences with curves there.

And is there any support in the most recent versions of KML and GML? The uptake of GML seems a bit slow, while KML has been spreading rapidly throughout it's short life (so far).

Maybe it is time for shapefile v2, with support for bezi?r curves and Unicode... Or GML (or some other OpenGIS standard) to support that.

Shapefiles are robust and cool, but when was this "de facto standard" create? 10-15 years ago? The personal GDB format isn't spread that much outside ArcGIS, and definately not beyond windows (since it depends on Microsoft JET for backend database).

Or maybe I have missed some important development... ?
Hugo Ahlenius
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#2
Kartograph

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GML has provisions for bezier curves. Sadly, GML is more of a framework instead of a standard. Basically you have to define your own standard building upon the GML framework.
Add to that that most GML-"hype" comes from a company deeply involved in GMLs development [namely Galdos]. No bright future for GML, as far as I can see.

EDIT: Oh well and GML is the darling of academic cartographers power point presentations. Lets the professors look up to date and buzz-wordy. Open Source and all.
I fell for it, and was deeply disappointed about the realities of GML. If anybody can name some non-Galdos example of GML as a real standard and something worhtwhile to look into, I?ll greatly appreciate.

#3
frax

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The main big champion of real-life use of GML, isn't that the Ordnance Survey? (uk national mapping authority)

I have a feeling that GML is more of a transfer format too, which is not bad per se, but it is not the new shape-file (your swiss army knife and lowest common denominator of vector data).
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#4
Hans van der Maarel

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The main big champion of real-life use of GML, isn't that the Ordnance Survey? (uk national mapping authority)

I have a feeling that GML is more of a transfer format too, which is not bad per se, but it is not the new shape-file (your swiss army knife and lowest common denominator of vector data).


The Dutch Topographic Service is in the process of moving everything to a GML-based setup.

My biggest problem with GML is that it's essentially not a format, but a concept. The resulting files are essentially useless if you don't have a document with explanations/translations with it.

Personally, I have no problem whatsoever using a proprietary data format such as shape or mid/mif, as long as its:
- widely used and supported
- consistent (so no DXF)

I don't really care about whether it's "open" or not. Whether I can work with it is much more important to me.
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#5
CHART

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XML is probably the fastest growing syntax used in developing applications.
Anyone can create his or her own xml structured file and give it a name. (or use an existing xml format and modify it for their own use)
An xml file NEEDS an Application...that will parse and use the content in a specific way.

So for example, the problem with SVG is not its structure or syntax but the lack of (or the limited) applications that can use it. e.g. Illustrator will read and write an svg file but they have drop the development of their SVG viewer... (because nobody wanted to install the viewer and it requires good java-script code for it to be cross browser ready...) They also bought Marcromedia Flash which can make use of the power of xml via its xml parsing tools.
So with Flash you can parse any xml structured file. Thus it can make use of SVG, GML, GPX ect .. in whatever way you intend.

If the Dutch Topographic Service make use of GML then you have a new application, and a growing base of requirements for GML.

For example I use the gpx (gps format in an xml) extensively to move data between MapInfo and Garmin units. It is simple to write an application that can parse through an xml file and convert it to the format of your choice.

KML is nothing without Google... you need the app.

Beziers are supported by GML and SVG but you need the application that will use it.

Most developers will tell you that xml is here to stay because of its flexibility.
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#6
David T

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Shapefiles are robust and cool, but when was this "de facto standard" create? 10-15 years ago? The personal GDB format isn't spread that much outside ArcGIS, and definately not beyond windows (since it depends on Microsoft JET for backend database).


In ArcGIS 9.2 (which is due out mid-November), ESRI is moving into a non-platform dependent solution for the geodatabase.

I don't have my notes in front of me, so I can't give you the exact terminology. But, I believe it will be called a 'File Geodatabase'. This new format will not have the limitation of a Microsoft Access database (2 GB limit). At the ArcGIS 9.2 Rollout Seminar that ESRI was giving a couple of weeks back, I know they were happy that the File Geodatabase could live in a Linux environment.
David Toney, GISP
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#7
pghardy

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In ArcGIS 9.2 (which is due out mid-November), ESRI is moving into a non-platform dependent solution for the geodatabase. I don't have my notes in front of me, so I can't give you the exact terminology. But, I believe it will be called a 'File Geodatabase'. This new format will not have the limitation of a Microsoft Access database (2 GB limit).

Yes, it is called the 'File Geodatabase', but is actually a folder of files. This means that each feature class can be up to 1TB in size (should be enough for most cartographers for a while).

There are also two new kinds of SDE geodatabase (personal and workgroup), which use SQL Server Express.

The personal geodatabase (MDB) is still supported, but file geodatabase becomes the preferred form (smaller, faster, portable, more scaleable, ...).

See 9.2 online help on Types_of_geodatabases for more info.

On the subject of Beziers (yes I know it should have an accent), ArcGIS has supported them in the object model, the desktop application and in the personal geodatabase for some time, but didn't have a user interface for creating and manipulating them. However, in ArcGIS 9.2, the new Cartographic Representations facilities come with a new editing toolbar that has a Bezier tool for this task.
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Paul Hardy
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