Ortophotos and map performance

[Søren Breddam]

Hi Listers,

 

Just a quick one (or two):

• Does an ortophoto that is turned off in the layer control affect map performance? (I.e. panning and zooming)
• Does an ortophoto that is turned on in the layer control but not shown affect map performance? (I.e. panning and zooming)

I've got a buttonpad that loads six different photos and I wonder if it is worth while to close the not shown ortophotos.

 

 

Venligst/regards
Søren Breddam GIS-koordinator
sor...@stevns.dk
Hovedgaden 46	Telefon:	+45 56 57 57 57
DK-4652 Hårlev	Direkte:	+45 56 57 51 71
www.stevns.dk	Mobil:	+45 28 95 30 34

 

 

 

 

 

 

 

[David Reid]

At least in MI v6.5

 

(Does an ortophoto that is turned off in the layer control affect map performance?)  Absolutly, it speeds performance in terms of redraw if the ortho is TURNED OFF

 

(Does an ortophoto that is turned on in the layer control but not shown affect map performance?)  Absolutly, regardless if the ortho is hidden by a solid color polygon or off the screen, performance is slowed because of redraw even though the ortho is not visible.

 

Again, this is the case with my installation of MI v6.5, the orthos my company have, reach 20,000px width, 400mb on disk

 

David Reid

Colbert County 9-1-1

Colbert County, Alabama USA

 

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From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] On Behalf Of Søren Breddam
Sent: Friday, November 06, 2009 10:07 AM
To: mapi...@googlegroups.com
Subject: [MI-L] Ortophotos and map performance

[Søren Breddam]

Hi David,

 

Thanks for your reply!

I should perhaps explain a bit. (My first question should be extended with 'when another orthophoto is active' )

I could have perhaps six orthophotos loaded in the map. Some could be active but hidden by another ortho - some could be turned off, depending of my custom Ortho layer control.

Does it affect map performance if I e.g. had several orthoes shown in the layer control but overlayed by another and therefore not visible?

I could close the photos that are not shown but I'rather not because of the load time... Should I bother closing the photos that are not shown to gain map performance?

r. Søren

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Fra: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] På vegne af David Reid
Sendt: 6. november 2009 19:57
Til: mapi...@googlegroups.com
Emne: [MI-L] Re: Ortophotos and map performance

[brian cooper]

For a planning exercise I have origin and destination data only, but need to estimate the road distance which would approximately be equal to the sides of the triangle if the direct distance was the hypotenuse. How does one calculate the vertical and horizontal distances, assuming C^2 = A^2+ B^2.

 

Brian cooper

[Uffe Kousgaard]

Hi,

Do you refer to http://en.wikipedia.org/wiki/Manhattan_distance ?

That is just A+B.

Unless your horizontal distance refers to 3-D in some way.

Regards
Uffe Kousgaard

[Lars I. Nielsen (GisPro)]

Hi Søren,

Any raster layer can be semi-transparent, so one cannot assume, just because one layer is below another, that it's invisible.

So, if a raster layer is turned on, and it intersects the mapper window, it definitely will be included in the rendering proces, using up performance.

Best regards / Med venlig hilsen
Lars I. Nielsen
GIS & DB Integrator
GisPro

Søren Breddam skrev:

[Bill Thoen]

Here in the Wild West USA where they lay out the streets North to South
and East to West (so you can have the sun in your face both driving to
work and coming home) we call that the "dog leg distance" and it's
calculated using the coordinates of your origin (Ox, Oy) and destination
(Dx, Dy) like so:

A=distance(Ox,Oy,Dx,Oy,"mi")
B=distance(Dx,Oy,Dx,Dy,"mi")
'dog leg' distance = A + B

--
- Bill Thoen
GISnet - www.gisnet.com
303-786-9961