[mapserver-users] Scalebar (and C# mapscript) issue

[Hulbert, Brian]

Murty,

 

It works fine for me using MapServer 5.0.2 with an equirectangular
projection using a WGS84 geoid reference whether I'm zoomed to a world view
or to a street-level view.  Be sure you are setting the scalebar units
member accordingly in C#.  For example, scalebar.units =
(int)OSGeo.MapServer.MS_UNITS.MS_FEET  to set the units to feet.

 

However, I have noted that it will appear garbled and squashed in width if
you use units which are not meaningful for the current zoomed area.  In
other words, don't use inches when zoomed to a city or world view.the
numbers are too large to display properly.   Write a routine that sets the
appropriate units based on the delta degrees that you are showing.  For
example, if the user chose English units (versus metric) and the current
viewport spans roughly ~0.5 nautical miles, then set the units to inches.
If the viewport is > 0.5 NM and < 1 NM, set the units to feet.  Otherwise
(the viewport spans more than 1 NM), set the units to miles.  You can tweak
this idea to suit your needs but this works well for me.

 

Brian

 

NOTE: The views expressed are the author's and do not necessarily reflect
the official position of LinQuest Corporation or any of its subsidiaries or
the organization providing Internet access.

 

From: mapserver-users-bounces at lists.osgeo.org
[mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Murty Maganti
Sent: Friday, February 13, 2009 2:20 PM
To: mapserver-users at lists.osgeo.org
Subject: [mapserver-users] Scalebar (and C# mapscript) issue

 

Hello

 

I am having strange issue with scalebar. I have scalebar displayed on map
(embed) and scale units are set to miles. It has size of 200x10 pixels. It
shows up fine on the map. Then at run time  (using C# map script), I just
change the units to feet or meters and the bar size shrinks (to almost 10
pixels length), which appears strange to me. Why would the scalebar length
changes by changing units. Is there any other setting I need to set to
maintain the same scalebar size?

 

This works fine (or not noticeable) for maps which have extents at city
level. I am testing on map which displays Ontario province (Canada). Also,
you need to have projection elements defined at both map and layer level. In
my case, the projection is same (WGS 1984).

 

Thanks

Murty

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