Re: [OpenMap Users] MRGS layer? Azimuthal layer?

Hi Piotr,
On May 17, 2004, at 2:30 AM, Piotr Kaminski wrote:

> Don,
> My problem with MGRSLayer was coused by my misunderstanding
> of UTM and MGRS coordinates. I've seen palette for UTMGridPlugIn
> and I've displayed both UTM zones and MGRS grid squares but I thought
> that those squares was UTM feature, not MGRS.
> Correct me if I'm wrong:
> - UTM defines zones
> - MGRS defines squares

The difference between the two isn't apparent on the map, it's how
their coordinate notation differs. UTM still has the squares as well,
it's just that the notation for referencing them is different.

> I think it would be clearer for users if we change palette a little:
> - change CheckBox - 'Show 100km Distance Grid' to 'Show MGRS squares'
> It should enable/disable displaying of MGRS squares.

I'm uneasy about this, because UTM coordinates are usually defined in
terms of those 100km distance markers, in their northing and easting
coordinates.

> - add '100km' to ComboBox and label it 'MGRS squares'
> It should be disabled when 'Show MGRS squares' is not checked
> Default value should be 100km.

I can see why you would suggest that, but there is a reason the 100km
grid is separate from the others. The difference here is that the
100km grid is shown in reference to the active zone of the projection,
and the lines that are displayed never change for different projections
as long as that zone is active (the center of the current projection).
The distance grid lines turned on for the option menu, though, changes.
  Only the grid under the center of the projection is displayed.

> What do you think about that?

We could have a flag that slants the labels to a UTM view or a MGRS
view. I guess I was trying to make the layer more useable for general
use, for people who didn't really understand what the MGRS coordinates
represent, and was letting the labels tie the two (UTM MGRS) together.

Once we internationalize the class you can change the names to fit your
users.

I really appreciate the feedback.

- Don

> ----- Original Message -----
> From: "Don Dietrick" <dietrick@bbn.com>
> To: "Piotr Kaminski" <Piotr.Kaminski@ctm.gdynia.pl>
> Cc: <openmap-users@bbn.com>
> Sent: Monday, May 17, 2004 1:08 AM
> Subject: Re: [OpenMap Users] MRGS layer? Azimuthal layer?
>
>
>>
>> On May 16, 2004, at 5:35 AM, Piotr Kaminski wrote:
>>> I didn't know that. I will try to configure it. If it will work the
>>> same way
>>> as for UTM grid it is enough for me.
>>
>> There are controls for modifying it's behavior on the palette, I think
>> the API will let you control it, too.
>>
>>>>> Another qustion is for AzimuthalLayer. Has someone already write
>>>>> such
>>>>> layer and could send source code to be added to OpenMap's codebase?
>>>>
>>>> What would an AzimuthalLayer render?
>>>
>>> Maybe I used wrong name for that layer. It is simple translation of
>>> Polish name for that kind of grid. I expect drawing of concentrical
>>> rings with additional 'ticks' for azimuth values from 0 to 360
>>> degrees. Such layer is often used in our applications on a ship or
>>> aircraft. The grid is anchored in the center of displayed map. Map
>>> center is periodicaly moved while ship is moving (sometimes map is
>>> also rotated to match current course of vessel). Rings are used to
>>> determine ranges to other objects on map. Ticks helps to determine
>>> bearing.
>>
>> Kind of sounds like an OMRangeRing, but the OMRangeRing doesn't have
>> ticks by default.
>>
>> - Don
>>
>>
>> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>> Don Dietrick, dietrick@bbn.com
>> BBN Technologies, Cambridge, MA
>> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>>
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=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Don Dietrick, dietrick@bbn.com
BBN Technologies, Cambridge, MA
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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