McIdas V and hurricane tracking map ?

[francoisborel]

Hello Bob, i hope all is okay for you.
Hello everyone,

I will try to explain my question in my bad english. Sorry in advance for the headache ..

I attach a picture named illustration.jpg.

I have made a color table for the storm/hurricane scale, and display on a map the track. All is okay on that.

BUT :

I saw that the change in the color is not "suddenly" appears. Between two points with to différent scale (for example, the first point in category three and the second in catagory four), the color of the line doesn't change directly at the next point. beetwen the first and the second point, the color change "slowly", gradually..

I put two red circle in my picture to show that. At the right, we not pass directly from green to yellow, we are going to yellow by passing by different colors (transition). So the green, and a green more clear, and another green more clear again, and a yellow with some green, and finally, when we arrived to the point where category one is reach, we have the really yellow.

A second exemple, with two marks in red.
On the first red cross, east of Guadeloupe and Dominica, the hurricane is pointed as Cat 3 in hurdat. On the second cross, just west of Guadeloupe, the hurricane is Cat 4.

What i would like to have ? A unique color line. So between the first and the second red cross, i would like to have a line in red (just red). And the line must become purple direcly at the point west of Guadeloupe, and NOT becoming, step by step, purple from the first red cross..

On the picture, with this format of color change, we can think that CLEO passed Cat 4 on south of Guadeloupe. In reality, he passes Cat 3 and become Cat 4 just west of Guadeloupe.

I hope you will understand something with my strange english .

The question : How can i have, on the line, always on unique color ? The change in the color must occurs directly on the point which change in intensity, and NOT color change gradually between two points.

Thank you for all.

Best Regards and have a nice day..

françois

[francoisborel]

Example file..

[bobc]

Hello -

Thanks for your thorough description of the problem as well as the image. As you've seen, it looks like the code behind the Track/Trajectory Colored By Parameter display types interpolates the color between data points instead of producing a solid color. I'm not seeing any easy way to work around this as-is. I wrote this up as an enhancement in Inquiry 2578. I've added a note to contact you if/when this functionality is added to McIDAS-V, but I can't make any promises on when this work will be completed.

Thanks -
Bob

[francoisborel]

Hello Bob

I'm sorry for this late answer.

Thank you a lot for your answer and what you decided to do.

Have a nice week
françois

[francoisborel]

Good morning Bob,

I'm sorry to return on this case but i'm not able to make what i have done with your advices.
All in this topic is okay for me, except the loop.

I make all of my maps since several months, and now i return on this fonctonnality to make an animated GIF on the track (what you are explaining in page 1). But i can do it now. So perhaps i forget a simple thing.

Could you help me ?

Here is my informations.

The txt file is like this :
196408201800,13.1,-44.3,5
196408210000,13.4,-46.8,15
196408210600,13.7,-49.1,15
196408211200,14.1,-51.3,35
196408211800,14.4,-53.5,35

In the point data parameter, all is OK/
Date in yyyyMMddHHmm format, latitude/longitude in degrees and the last one in mi/hr.

I make a personal color table for each class Saffir Simpson (so : 5,15,25,35 etc ...).

To make my animated gif, here is what i do.
1- I open my data source with to good Data Point Parameters
2- In the Fields, i choose "Track" and "Force", my fourth parameter (class Saffir Simpson)
3- In the display zone, i choose "GridTrajectory" and the first option below, "Trajectory Colored By Parameter"

I click on "Create Display" and my map is OK.

So i go in the menu "View .. Capture .. Movie", and on the movie capture Window, i click on "Time Animation".

After that, McIdas allows me to save the file in a animated gif format but the gif only displays the map with all the track line, not an animation ...

Thank you Bob for your help and sorry to return on that. Damned !

Sincerely
françois

[bobc]

Hello françois -

It looks like you are doing everything correctly. When I go through your process, I'm able to capture an animated GIF that animates through the trajectory:

Before you capture your movie, are you able to play through the loop using the time animation widget in the Main Display and see the track animate? Are you displaying any other data along with your track? I've tested this so far on Windows 7. Are you on a platform different than Windows (e.g. Linux, OS X)?

Thanks -
Bob

[francoisborel]

Hello Bob,

Thank you...

No.. When i click on the play button, anything happened. I stay with my entiere track line .. Very curious.

I attach 3 pictures, which illustrate what i do. Perhaps you will see something on that. You have :
- the data point parameter windows
- the field selector
- the final result.

Thank you a lot. Very strange ..

Cheers
françois

[bobc]

Hi françois -

I think I see what's going wrong. In your Point Data window, you set your first row for:

196408201800

... as "Date". Change "Date" to "Time" and things should work as expected. If this doesn't fix things, let me know.

Thanks -
Bob

[francoisborel]

Yes ! Very good Eye Bob !
Time format, and not date !

It's work now.

BUT (lol), i have a second problem. The line not displays the color of my color table.

I attach my example <cleo.gif>. This is hurricane CLEO (1964). My "Force" parameter have a color table .. < see attached file <cleo_table_color.jpg>. and the animation doesn't display it (only blue in the line)..

Something wrong again ?

Thank for Bob.
Cheers
françois

[bobc]

Hello -

When capturing your movie, after clicking Save Movie the Save window appears. On the right side of this Save window, uncheck "Use 'global' GIF color palette" and click Save. At this point, your movie should save better.

From the Image and Movie Capture Controls page of the McIDAS-V User's Guide:

When saving a movie, in the Save dialog, there is an option for 'Use 'global' GIF color palette'. This option is applicable for animated GIF movies, and it is enabled by default. Animated GIFs are limited to 256 colors, and this option uses the same 256 colors for every frame in the loop when the setting is enabled. Enabling this option allows for certain display settings such as a color scale to remain constant throughout the loop. If this option is disabled, then each frame uses it's own color palette, so one color may represent one value in one frame, and the same color may represent a different value in the next frame. One circumstance where disabling this option may be ideal is if the movie starts with a low-light scene (not many colors) and there is no color scale in the display.

With this "Use 'global' GIF color palette" checked, then the only colors included in your animation will be those included in the first frame, which was blue. Unchecking this allows each frame to use its own 256 colors, allowing for the purple/red colors to appear later in the track.

If this doesn't work, or if you have any other questions, please let me know.

Thanks -
Bob