[fdo-users] view scale

Orest Halustchak orest.halustchak at autodesk.com
Fri Feb 15 08:55:08 EST 2008


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.


-----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.

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?

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