[fdo-users] view scale

[Orest Halustchak]

Hi Artyom,

Just to clarify, what scale do you need to find? By "view scale" do you mean the scale between a map display and ground coordinates (e.g. 1:20,000)? If that's really what you mean, then FDO itself has nothing to do with that scale. FDO is independent of any map display. Scale would have to be computed outside of FDO.

Thanks,
Orest.

-----Original Message-----
From: fdo-users-bounces at lists.osgeo.org [mailto:fdo-users-bounces at lists.osgeo.org] On Behalf Of Artyom
Sent: Friday, February 15, 2008 9:36 AM
To: fdo-users at lists.osgeo.org
Subject: RE: [fdo-users] view scale


Our data type does not have a measure information. We have type of objects
that contains some attributive information but mostly it xyz. And to read
our data not enough to know only current extent.
About the coordination system can't say anything concrete for now. Because I
need to convert our coordininate system to WKT. now I use only default
system. I'll research this question a bit later. And by the way my provider
is unmanaged. I couldn't find the entry point for managet connection wich
could be equivalent to the unmanaged FdoIConnection* CreateConnection (). So
if there is any way to find the scale not using the measure value? Or it can
be done by FDO spatial utilities?

Thank you for you replies!



Orest Halustchak wrote:
>
> Hi,
>
> Artyom, FDO itself deals with data access and has nothing to do with view
> scales or other view / rendering attributes. That's up to client
> applications such as MapGuide. The data itself is stored in units defined
> by the CRS as Maksim points out. Even M (measure) values that might be
> stored are not tied to any view or view scale. They often are based on
> ground distance, but can be other units as an application may define.
>
> Thanks,
> Orest.
>
> -----Original Message-----
> From: fdo-users-bounces at lists.osgeo.org
> [mailto:fdo-users-bounces at lists.osgeo.org] On Behalf Of Maksim Sestic
> Sent: Friday, February 15, 2008 5:24 AM
> To: fdo-users at lists.osgeo.org
> Subject: RE: [fdo-users] view scale
>
>
> OSgeo::FDO::Geometry::DirectPositionImpl has M() property - it represents
> a
> Measure related to given coordinate. It's on you to implement parsing of
> the
> measure information and extracting something meaningful out of it.
> Geometry,
> as it is, doesn't posses a scale - it's unitless by default.
>
> On the other hand, FeatureStore may have CRS (Coordinate Reference System)
> set. CRS establishes soft spatial relation between the "space" (container)
> and geometric entities placed in it. It's definition does posses measure
> info, just look under UNITS part of CRS WKT string.
>
> Regards,
> Maksim Sestic
>
>
>
> Artyom wrote:
>>
>> I'm developing an Fdo provider. And I need scale, no metter if it is
>> MapGuide or AutoDesk Map 3D. Is it possible to get the scale by FDO? Or
>> my
>> problem has no solution?
>>
>
> --
> View this message in context:
> http://www.nabble.com/view-scale-tp15432859s18162p15497822.html
> Sent from the fdo-users mailing list archive at Nabble.com.
>
> _______________________________________________
> fdo-users mailing list
> fdo-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/fdo-users
> _______________________________________________
> fdo-users mailing list
> fdo-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/fdo-users
>
>

--
View this message in context: http://www.nabble.com/view-scale-tp15432859s18162p15502118.html
Sent from the fdo-users mailing list archive at Nabble.com.

_______________________________________________
fdo-users mailing list
fdo-users at lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/fdo-users