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TOPIC: Matisse accuracy

Matisse accuracy 13 years 6 months ago #1468

  • Dufour
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Hi,

I digitized bathymetry of a map to get coordinates in Lambert93.

Then I imported the coordinates in matisse. But the problem is the following:

Matisse rounded too much coordinates, so the depth contours are found completely distorted.

Capture_1.jpg


I tried to change the accuracy of matisse but this changes nothing ...

Can you help me?

Regards
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Re:Matisse accuracy 13 years 6 months ago #1479

  • Dufour
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Hi,

My area measuring 100m x 100m, is it too small?

I feel that the accuracy of matisse is about 20m ... I digitized a point every 2-3m, as well matisse several points are exactly in the same place. How to fix this?


Regards.
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Re:Matisse accuracy 13 years 6 months ago #1480

  • c.coulet
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Hi

No your area is OK. But maybe the coordinates (Lambert93) was too high to allow a really fine accuracy of the project! Did you work in a local referential or using the full coordinates?

Another possibility comes from the import filter...

Regards
Christophe
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Re:Matisse accuracy 13 years 6 months ago #1483

  • Dufour
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Hi,

I used the full coordinates(approximately X = 950000 and Y = 6220000). But the accuracy of my points is the order of 10^-8, and matisse rounded to 10^-1 ... So I have lots of duplicates and the accuracy is bad.

I tried to work in a local referential but I can not. Can you explain how?

Thank you very much.

Regards
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Re:Matisse accuracy 13 years 6 months ago #1486

  • c.coulet
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Hi
You created a Matisse project with an accuracy of 1.E-1 (that the only way for you to manage such coordinates). So at the import step, the accuracy is set to the project accuracy.

You should create your own local referential for example by a shift of your coordinates of (-950000, -6220000). You will obtain small coordinates and then you can create a project with an higher accuracy (1.E-4 for example).

Keep in mind that it's totally incredible to really have an accuracy of 1.E-8 in space. The millimetre (1.E-3) or more often the centimetre (1.E-2) is more realistic.

Regards
Christophe
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Re:Matisse accuracy 13 years 6 months ago #1487

  • Dufour
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Thank you very much ...

In fact, I had a problem in my point file, the accuracy was 10^-1 and not 10^-8 ... Still, Matisse has rounded the new points.
So I made a change of coordinates as you said (-950000, -6220000), then dropped precision (10^-6). Now it works...

Once again thank you very much...

Regards
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Re:Matisse accuracy 13 years 6 months ago #1489

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OK

That's great
I lock this post

Regards
Christophe
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