Help: generating "meta - symbols" dynamically

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Help: generating "meta - symbols" dynamically

Burgholzer,Robert

I have a need to summarize my spatial data with what I will call a “meta-symbol”, i.e., a symbol that represents more than one data column, with more than one state for each column.  I could create a symbol file containing all of the combinations of such a symbol, however, this can become a very large group of symbols in very short order.

 

For example, I have a map which shows geographical regions, and I wish to summarize the drought status of each of those entities for 4 different metric: 1) rainfall, 2) stream flow, 3) groundwater levels, and 4) reservoir storage values.  I have 4 categories of drought indicator: 1) no drought, 2) drought watch, 3) drought warning, and 4) drought emergency.  I believe that this makes my number of possible combinations, 4^4, or 256 different categories.  If I were to add a 5th indicator, then I would end up with 5^4 possible combinations, or 625 different combinations.

 

One possible approach that I have thought of is to create a rectangular grid (with cells for each indicator) for each geographic area, located at its centroid, then place a symbol in each grid cell.  This would reduce the overhead to 4 symbols, that would then be dynamically assigned by mapserver to the drought value.   I am concerned about registering these properly within the cell.

 

Any feedback on my proposed approach, or examples of something similar would be appreciated,

 

Thanks in advance,

r.b.

 

Robert W. Burgholzer

Surface Water Modeler

Office of Water Supply and Planning

Virginia Department of Environmental Quality

[hidden email]

804-698-4405

Open Source Modeling Tools:

http://sourceforge.net/projects/npsource/

 

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Re: Help: generating "meta - symbols" dynamically

Burgholzer,Robert
Thanks Bobb,
I will look into that.  After posting, I got to thinking, and I am
experimenting with using a pie chart (of fixed percentage), trying to
work out a dynamic color for the pie slice.   Your approach seems a bit
more robust to be sure, although I am not sure I totally understand how
to go about it.

With your approach, would this be a set of CLASS'es that turn themselves
on/off based on a condition?

FWIW it would be interesting to look at expanding the Chart type to
contain more types, that could be used to achieve this type of effect as
well.

Thanks again!
r.b.

Robert W. Burgholzer
Surface Water Modeler
Office of Water Supply and Planning
Virginia Department of Environmental Quality
[hidden email]
804-698-4405
Open Source Modeling Tools:
http://sourceforge.net/projects/npsource/

-----Original Message-----
From: Bob Basques [mailto:[hidden email]]
Sent: Tuesday, February 19, 2008 2:48 PM
To: Burgholzer,Robert
Subject: Re: Help: generating "meta - symbols" dynamically

Robert,

What about using a stacked symbol type, something where you could see
any of the particular symbols, but they are all stacked on top of each
other depending upon whether they apply or not.  Then you only need a
fairly small set of pre-defined symbols, but the combinations take care
of themselves based on the symbol stack that is displayed.

bobb





Bob Basques
GIS Systems Developer
City of Saint Paul, MN

GISmo
Powered by
GeoMOOSE




>>> "Burgholzer,Robert" <[hidden email]> wrote:

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I have a need to summarize my spatial data with what I will call a
"meta-symbol", i.e., a symbol that represents more than one data column,
with more than one state for each column.  I could create a symbol file
containing all of the combinations of such a symbol, however, this can
become a very large group of symbols in very short order.=20

=20

For example, I have a map which shows geographical regions, and I wish
to summarize the drought status of each of those entities for 4
different metric: 1) rainfall, 2) stream flow, 3) groundwater levels,
and 4) reservoir storage values.  I have 4 categories of drought
indicator: 1) no drought, 2) drought watch, 3) drought warning, and 4)
drought emergency.  I believe that this makes my number of possible
combinations, 4^4, or 256 different categories.  If I were to add a 5th
indicator, then I would end up with 5^4 possible combinations, or 625
different combinations.

=20

One possible approach that I have thought of is to create a rectangular
grid (with cells for each indicator) for each geographic area, located
at its centroid, then place a symbol in each grid cell.  This would
reduce the overhead to 4 symbols, that would then be dynamically
assigned by mapserver to the drought value.   I am concerned about
registering these properly within the cell.=20

=20

Any feedback on my proposed approach, or examples of something similar
would be appreciated,

=20

Thanks in advance,

r.b.

=20

Robert W. Burgholzer

Surface Water Modeler

Office of Water Supply and Planning

Virginia Department of Environmental Quality

[hidden email]

804-698-4405

Open Source Modeling Tools:

http://sourceforge.net/projects/npsource/

=20


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<div class=3DSection1>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>I have a need to summarize my spatial data with what
=
I will
call a &#8220;meta-symbol&#8221;, i.e., a symbol that represents more =
than one
data column, with more than one state for each column.&nbsp; I could =
create a
symbol file containing all of the combinations of such a symbol, =
however, this
can become a very large group of symbols in very short order. =
</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>For example, I have a map which shows geographical =
regions,
and I wish to summarize the drought status of each of those entities for
=
4
different metric: 1) rainfall, 2) stream flow, 3) groundwater levels, =
and 4)
reservoir storage values.&nbsp; I have 4 categories of drought =
indicator: 1) no
drought, 2) drought watch, 3) drought warning, and 4) drought =
emergency.&nbsp; I
believe that this makes my number of possible combinations, 4^4, or 256
different categories.&nbsp; If I were to add a 5<sup>th</sup> indicator,
=
then I
would end up with 5^4 possible combinations, or 625 different =
combinations.</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>One possible approach that I have thought of is to =
create a rectangular
grid (with cells for each indicator) for each geographic area, located =
at its
centroid, then place a symbol in each grid cell.&nbsp; This would reduce
=
the
overhead to 4 symbols, that would then be dynamically assigned by =
mapserver to
the drought value.&nbsp;&nbsp; I am concerned about registering these =
properly
within the cell. </span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Any feedback on my proposed approach, or examples of
something similar would be appreciated,</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Thanks in advance,</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>r.b.</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Robert W. Burgholzer</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Surface Water Modeler</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Office of Water Supply and Planning</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
  font-family:Arial'>Virginia</span></font><font size=3D2 =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial'> </span></font><font =
size=3D2
  face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>Department</span></font><fo
n=
t
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'> of
Environmental Quality</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><a =
href=3D"mailto:[hidden email]">[hidden email].
g=
ov</a></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>804-698-4405</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Open Source Modeling Tools:</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><a =
href=3D"http://sourceforge.net/projects/npsource/">http://sourceforge.ne
t=
/projects/npsource/</a></span></font></p>

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style=3D'font-size:
12.0pt'>&nbsp;</span></font></p>

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