Moving Region Creator
=====================
Getting the Region Data
-----------------------
This simple tool can create a moving region from a static one.
The region must be given as nested list in any file. You can get such
region data from any database containing simple regions.
For example, to get the county 'Altmarkkreis Salzwedel' from the database 'germany',
you have to (assumed the database germany is restored already):
- start the SecondoServer and Javagui
- perfom the following commmands:
open database germany
query Kreis feed filter[.KName contains "Salzwedel"] extract [Gebiet]
- After that, press the save button in the Javagui and save the result
into a file.
Creating a File describing the Transformations
----------------------------------------------
The second thing you need is a file containing the wanted transformations.
This file must also be in nested list format. The list structure is:
( (<affine transform>) (<affine transform>) ... )
Each affine transformation is used to build a single unit. The interval of this
unit can't be changed in this implementation. It is fixed to be six hours. Also
the start time can't be changed.
Each affine transformation is a composition of a basic affine transformation.
As a nested list, the structure is:
<affine transform> = (<basic transform> <basic transform> ... )
A basic transformation is one of rotation, scale or translation.
Note that a rotation exceeds the abilities of our model for moving regions.
This is implemented for completness of the affine transformation.
The same thing is a scale with a factor of or less than zero in any direction.
Furthermore, the value for the x and the y scale must be equal to ensure
parallel lines.
Neverless, you can animate such 'invalid' moving regions using the Hoese Viewer.
Summarized, a valid transformation can only consist of
any translation and scale where the values for the x and the y scale are
equals and greater than zero.
The basic tranformation has the format:
Translation:
( translate (<dx> <dy>))
Scale:
( scale (<sx> <sy>))
Rotation
(rotate <angle>)
dx, dy, sx, sy, and angle can be of type integer or of type double.
You can find examples of transformation files in transform1 ... tranform4.
Note that transform3 uses a rotation. The result will be nice in the HoeseViewer
but invalid for mnoving region data.
Calling the tool
----------------
First, you have to compile the required tools using make.
After that, call the tool in the following way
lintransform <regionfile> <transformation file> <output file> [init]
where
<regionfile> : name of the file containing the region data
<transformation file> : name of the file containing the list of affine transformations
<output file> : name of the file to create, Note that no check is performed whether
the file exists. If a file with this name exists, it is overwritten
without asking the user
[init] : this is an optional parameter. If this parameter is given, the first
transformation is not used to create a unit. In this case, the
first transformation prepares the data of the region for further
processing.
Using the created data
----------------------
The moving region written in the <output file> can be read into Javagui using the load button.
You can animate it in the familiar way. If the MovingRegionAlgebra is included in the
Secondo system, you can also use the 'store' button for creating a database object from the
data.
