[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

20020124: radmap NEXRAD resolution

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: 20020124: radmap NEXRAD resolution
  • Date: Thu, 24 Jan 2002 14:25:16 -0700
Ken,

Most of the NIDS data is sent in radials, not as a raster.
An approximate raster size is ~460x464 pixels. The size of the
resolvable data point changes with the range gate however.
The radmap program comes from TDL with many hardcoded defaults
to eliminate user input. I don't know why 620 was chosen.
You can compile the program with your own needs.

Steve Chiswell
Unidata User Support

On Sun, 13 Jan 2002, Ken Poore wrote:

> I have a question:
>
> The default image resolution for a single-site NEXRAD image generated by
> radmap is 620x620 pixels.  Why is this resolution used?  Is it based on
> the available resolution of the source data?  Or is just a convenient
> image size?
>
> The reason I ask is because I'd like to generate an image that
> represents a one-for-one data-to-pixel resolution.  I want to create the
> smallest image possible that will accurately represent the entire data
> set for a given NEXRAD product.  I think, though I may be mistaken, that
> some of the pixels in the 620x620 image are distorted because 620x620 is
> larger than the available data set.  In other words, if the data set
> only has enough data for a one-to-one image of 570x570 (for example) and
> it's scaled up to 620x620, there will be areas of the image where two
> image pixels are displayed for one bit of NEXRAD data.
>
> What got my curiosity going is that Weathertap has smaller images for
> the same (apparent) data set, and I'd rather have more compact images
> than stretched images.
>
> Thanks,
>
> Ken Poore
> Harvest, Alabama
>