Autor Thema: Raster Resolution Options  (Gelesen 3135 mal)

Offline Bob Sheahan

  • Jungbrut
  • *
  • Beiträge: 1
    • My/Mein Tackle Equipment: Scuba Spearfish
  • My/Mein Echo Equipment: Insight Planner
Raster Resolution Options
« am: 15 September 2017, 17:31:40 »
I need some additional information on the option selection for converting a Raster Map to AT5 map.  I have read every post and watched every video and I cannot find any discussion on the Resolution Options.   Most videos set the Min to 1 and the max to 16.   But what does this mean?
My GeoTIFF files consist of a TIFF and World file. The file is basically a colored contour picture of a natural reef 855 meters wide by 700 meters long and the TIFF files has 7769 x 6358 pixels with 8 bit color.  I have also made the original TIFF file into a NOAA type KAP file and it displays just fine in OpenCPN.   In OpenCPN my chart is initially outlined by a pink rectangle on a standard NOAA charts and when I zoom into the outline rectangle it gets bigger and bigger until my chart shows up and I can continue to zoom in up to a point.   So I am confused by the resolution selection in IMC as if you have different Min and Max values it creates multiple _3DTexture_xx.at5 files instead of the usually one file that I am used to and zoom in to.   So would you please describe the Resolution Options in detail and how they should be properly set depending on area and number of pixels in the source.  Examples are a big help.  Thanks.

Offline gregory

  • Insight Map Creator
  • *
  • Beiträge: 854
Re: Raster Resolution Options
« Antwort #1 am: 18 September 2017, 16:09:13 »
Resolution is defined in Lowrance Mercator Meters per Pixel (MM/pixel).  A Lowrance Mercator Meter is roughly equal to 1 meter at the equator.

Simply put, the native resolution is displayed from .75x to 1.5x of the resolution.  For example, a 4 MM/pixel image is displayed from 3 MM/pixel to 6 MM/pixel.

A Min of 1 and Max of 16 is creating layers at 1, 2, 4, 8 and 16 MM/pixel.