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COREL - raster callibration

COREL - raster callibration

COREL - raster callibration


I use to draw plans & maps using Corel - over scanned raster maps placed in background. Many GIS software and even simple GIS tools can do raster callibration - besed on known four corners or overlaid known mutual points. But, as far as I figured out - Corel does not.
Also, if you got a map in few scanned parts, to join them into single (composite - well adjusted one ) - it is not simple nor precise working with Corel.

Perhaps, here is Someone, who already faced himself mentioned above problem and discovered how to resolve it ?

I believe, it is the matter of some macros that could be created for Corel.

I will be grateful for any info about that.


RE: COREL - raster callibration

If you are talking about making panaramas then although PhotoPaint has a 'stitching' feature I personally don't find it easy to use but go to www.Serif.com and look up Panarama plus, very easy to use and if there is enough overlap makes a good job.
Alan D

RE: COREL - raster callibration

Thank You Brushman for your reply.

Foto panorama is not my concern. The topographic maps - are ! To join parts of a map, is also now out of the time, since there are many big-size scanners, that do the job in single run... The problem is - re-deformation of the scanned TIFF, which mean callibration of it's area - distorted during scanning, or because the map itself (the paper map) is distorted already because of humidity and so on. We are looking for the tool / macros from within Corel program that can do good callibration  = rectification of a raster map. This process is also called georeferencing - means that corsor over the map shows-back Lat/Long parameters. Also the map grid is comming back on its propper position.
But, anyway, thank You Friend for your reply.
Here , in Poland some programmers have started already its work on creating some macros in order to resolve its lack in Corel itself. As soon, as they create any, You will be informed.



RE: COREL - raster callibration

Not sure if I have your intentions right, but you want to "deform" a rectangular image by slightly moving one or more of its corners in or out, and having the pixels in the original rectangle remap themselves to new positions in proportion to those movements ... ???

Photopaint can do that :

a) open the image
b) use the rectangular mask tool to define your rectangle
c) object : create : copy selection
d) click on the new object, and click again. You should have little arrows at the four corners of the object.
e) drag the corners to where you want them
f) object : combine : combine objects with background.

Or possibly you need to do it the other way round, ie create a mask that is a distorted rectangle (using the freehand mask tool) and stretch it to fit a regular grid? In that case, make sure view : grid is on and adjust your grid size with view : setup : grid.

RE: COREL - raster callibration

Hio Harry,
Many thanks for your ans.

- First of all, forgive me - the language I'm using. For years had no contact with English, but with understan reading any problem.
1. If U scan a map - for many reason the scan itself got many distortions - scanner mechanical, paper deformation, humidity.
2. If U place such the scan on desktop, than if U generate mathematical and propper grid - coming from measurement and scale of the original map - as should be in right way - U will see that the grid in the scan and the mathematical grid NEVER match each other. And it is not linear distortion over the area, but in some parts it is for example 0,1 mm in some other 0,5 or so on.
For this reason - GIS soft - when calibrating and georeferencing the scan - has to make NON linear distortion within the scan.
To do that, one has to determine well known points, such the corners are, and it is the basic for measurement. Some GIS soft can do much more - accepting much more known points, not only corners. After that, the scan - nevertheless it is distorted after scanning - is distorted by the soft. in opposite way - what will effect and result that both the grids - the one on the scanned map and generatet manualy over the scan - would come very close to each other - almost perfect.
Such the operations result that reading pixel position on the scan - well represents GPS / carthographic position of the object.
This is called - georeferencing the scan.

After that - one can measure exact position of any terrain point just on the scanned map on desktop.
The map callibrated in that way - can be used to draw your own map - representing correct Lat / Long positions of any point drawn over the scan. If You print that map - You can say - the map is GPS oriented.

For ex. Ozi Explorer will do good callibration and one can travel with his laptop and GPS device tracking his waypoints and tracks.

I use to draw with Corel. For drawing is perfect to me, but lack of callibration tools for raster, I have to do that manualy, what is boring and NOT precise.

Even Corel DESIGNER X4 has no this option
and it is very pity.

Sorry once again if You got tired with reading this,
but, anyway - one day someone will create such the macros
and would make Corel - perfect tool for mapping too.

Stay cool, best regards and many thanks

Edgar / GISMAN

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