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| GeoCommunity Mailing List |
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| Mailing List Archives |
| Subject: | GISList: Workstation ArcInfo:selecting 'closest' year to selected year |
| Date: |
01/09/2002 12:42:29 PM |
| From: |
Charlene Howard |
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Hello list
I am in a bit of a bind right now, been looking at this a bit too long. I am
hoping someone out there has tackled this sort of issue at some point. I am
still using workstation version of ArcInfo, and most likely will be for the
entirety of this project.....
Basically, I am looking for a way to go through a table and select the
records that have a value for year that most closely matches the year a user
specifies earlier on. I have a big file of transportation links with a
unique A-B node combination, but there can be more than one year per A-B
combination, so a group of records can have the same A-B and different
years. There can, however, only be one year per A-B combination. Confused
yet?
The aim is to select all the records that make up a transportation network
for a given year. For example, if I want a 2005 network, I want to select
each A-B combination that has a year closest to 2005. If 3 records are
2001,2002, and 2003 for the same A-B combination, I would want to select
2003 since it is the change that happens closest to 2003. The idea I have so
far is to run statistics on the table (getting min and max year), and use
the resulting stats table (with one record per A-B combination) as the basis
for selecting links from the original table based on unique A-B combination,
in a cursor or something. Then, in the cursor, select the A-B link ID, and
somehow compare the years in the records that come up to ultimately
determine which link to use for the given network year. This is where I need
help!
Is this sort of comparison possible, especially in a cursor or other sort of
loop? In the past, when I have cycled through selected records in a cursor,
and tried to add to the selection set and then tried to move to the next
record in the cursor, it broke the cursor (I probably was doing something
wrong). Sorry if my questions are not clear, I am finding it hard to explain
everything I want to/ have to do with this. Any ideas, code samples, etc. on
how to be able to select in this way would be very appreciated, or if you
know this will not work, that is good to know too...........thanks!
charlene
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Charlene Howard
Metropolitan Washington Council of Governments
Washington, DC
(202) 962-3384
charlene@mwcog.org <mailto:charlene@mwcog.org>
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