Problem quilting home-made .kap with S-63

[bcn]

Under 4.1.925 (Win 8.1) and 4.0.0 (Debian) we are observing the following:

A BSB/.kap file generated with imgkap shows correctly with CM93 but when hiding the CM93 set only the .kap will be shown and not the as well available S-63 cell.
Tapping on the S-63 piano the S-63 will show up and the outline of the .kap. Zooming in will not bring up the .kap.

The .kap (this is a sounding track exported as png and then converted by imgkap - work in progress) is attached.

Hubert

[seandepagnier]

I could be wrong but from what I remember the quilting logic is a bit specialized for cm93, so maybe it cannot be possible to quilt raster charts with vector charts that are not cm93.

[bcn]

May be as we here never has tested with S-63 and raster.

People from the Channel and VisitMyHarbour sets should have done perhaps.

[bdbcat]

Hubert...

Re .KAP file and S63 charts.

What you observe is normal behaviour. Except for the special case of cm93, OCPN never attempts to quilt arbitrary Raster charts and Vector charts together.

This would certainly be possible to do, if we want to. It would change the user interface somewhat.

Take your test case for example. When you select and zoom in on an isolated .KAP chart, how should O decide which smaller scale chart family to us in order to fill out the quilt, presuming there are several options.? Use Raster? Use Vector? Use cm93? Today the policy is to use, in this case, raster. But you have no other smaller scale raster charts at this location. So we revert to cm93 (if available) only when there are no other small scale raster charts available on this viewport. In O4 and 4.1.x, we would not choose vector, even if cell coverage was available, as it is in your test case.

The situation would of course be reversed if you zoom in to a large scale vector chart.

Lets discuss further...

Hope this helps
Dave

[seandepagnier]

Could use any vector, not only cm93 when there is no raster chart to quilt. I am not really sure the correct solution.

In the future I think we need a third type of chart "imagery chart" for satellite images. These should not be treated the same as raster charts, and should be able to be blended ( with variable transparency ) as well as drawing only the land parts and leaving the sea to the nautical chart somehow.

When there are several imagery charts at a given location, some may be for different tides, so not sure how to handle that.

[bcn]

I do see two different topics here:

Quilting of vector and raster on one hand and Chart Layers as a second concept. The second case is interesting for charts with a defined opacity or charts with completely transparent areas where you want to see the underlying chart. Charts with holes if you want so.
The latter is the case in our sounding chartlet - instead or in addition of defining a polyline in the draw plug-in. The chartlet has the advantage that it will be portable even between different chart plotters.

Now the issue of quilting. It surprises me that this did not pop-up earlier by people that are using raster and vector in zones where both type of charts are in play. Or in the case of GE2kap generated charts in a vector envionment.

In the case of (S-57) ENCs we know that they are grouped by usage/scale
1 - Overview, 2 - General, 3 - Coastal, 4 - Approach, 5 - Harbour, 6 - Berthing and that charts of the same usage group shall not overlap. They are tiled.

So choose the best available scale independent from the type or group of charts to compose the quilted view.

For conflicts allow to hide group of charts (usage, Raster or Vector) as we have already the possibilty from the chart piano for single charts or CMs that are seen as asingle chart a the piano.

Conflicts: Raster and vector charts with the same scale or within the same usage band covering the same or overlapping zones. Count that the Hydrographic offices are issuing the same charts as raster and vector.

In oder the understand better: what is special with the CMs so that they lend to be quilted?

For sure I will have overseen issues but just to start a discussion and to have a clear idea about the object.

And how do you handle this situation today?

[rgleason]

Perhaps my use is different than others, but I tend to want to use only raster or only vector and have made Chart Groups accordingly, although O can handle both at the same time. I have not used Google satellite kap files much, but know it is favorite in the islands, etc.

I like the idea of having a transparency image layer for Weatherfax, IAC, Satellite overlays, etc.
Indeed, Sean was going to improve Weatherfax to use Kap, so that position information was retained.

Quilting: Earlier I was wondering why quilting to fill in and complete a screen did not occur more readily, and why when once quilted at a given scale, the quilt would not stay when you zoom out once or twice. Sometimes I've tried to force quilting by zooming in and then zooming out, and it does not seem to stick.

I realize that we have those wonderful buttons at the bottom which I do use, and generally I can get it the way I want it, but a little more sophistication in the quilting smarts might be helpful. - I realize it is a complex matter involving scales and cpu cycles. --PS I think this tends to be more of an issue with raster, although it happens with vector too. I will have to check this.

I've entered a FS#1869 Feature Request
FS#1869 : Charts - Rendering improve the first appearance/utility, rendering at large and intermediate scales