Re: [OpenMap Users] mapping layers, new shape layers.... I dont Y my questions are neglected.... Someone do reply

From: Don Dietrick <>
Date: Thu, 22 Sep 2005 00:53:05 -0400

Hi Kedar,

On Sep 18, 2005, at 3:49 PM, kedar myadam wrote:

> On 9/9/05, kedar myadam <> wrote:
> Hi,
> I posted my question(subject: "map exactly") couple of
> days back and for some reason no one replied me, may b i should be
> clear with my problem
> (Question: 1)
> I have a image and i added as a layer in Openmap. The
> layer i created represents 1500 kms in width and 1500kms in height.
> I place this at certain latitude and longitude. My Question is How
> to map it exactly?? I mean the distance covered by layer on the map
> should be 1500 kms, How could this be possible. For example the
> distance between Longitudes at Equator is 110 kms( i guess) .
> How can i map exactly if i have a image that represents 1500 kms
> and i want to center the image at Lat,Lon(27,-80).
> The program output looks something like this,

How exact do you need to be? You run into the problem where the
dimensions of the window affect the distance represented, and the
choice of projection type affects that, too. I suppose you could
configure the LamberConformalConic projection to fit the area you
describe, that's an equidistant projection. You'll have to find the
parameters of a state plane that works for that area of the earth.
OpenMap doesn't have a UTM projection, or I'd suggest using that.

But, in general for the other projections, you'd have to figure out
the corner coordinates of a box that would cover the approximate size
of the area you want. You can use the GreatCircle class to find a
location from the center of your area to 750 km E/W/N/S. Then, you
call the projection.getScale(...) method on your projection, with the
center of your area being the center of the projection, and pass the
coordinates of your box to that method. That will tell you the scale
you need to set on your projection for that approximate area.

> (Question : 2)
> How can i add more Shape layers, where can i get it from? I want
> something that looks more fancy. My professor was not impressed
> by the "Political Boundaries" layer, he wants something more good
> looking.

There is a FAQ entry on the website for some options. You might want
to try to find some background images or some DTED data, too.

- Don

Don Dietrick,
BBN Technologies, Cambridge, MA

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Received on Thu Sep 22 2005 - 00:54:01 EDT

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