<br>Thanks alot Markus for your reply.<br><br>May I ask some more questions please to better understand the dataset?<br><br>FT_COST;Enhance Routing - Travel time in minutes <- does this mean the time in minutes taken from Target Id to Source Id depending on the "speed" column?
<br>TF_COST is Source ID to Target Id right?<br><br><br>And taking the lenght as the cost of going through that node in a routing network, am I right in the following conclusions :<br><br>- I can make another column length with the value of length(the_geom)
<br>- If street is BI-directional, thus one_way = "BI", that means that cost = length and reverse_cost = length<br> - If street is TF directional, thus one_way = "TF" that means that cost = length and reverse_cost = 1000 + length (made 1000 as a big number so for sure it is not included in the routing)
<br>- If street is FT directional, thus one_way = "FT" that means that cost = length + 1000 and reverse_cost = length<br><br>Now on the dataset is 1000 a huge number? Should I reduce it to a smaller number / increase it to a bigger number / make it negative?
<br><br>For my routing I am using pgRouting.<br><br><br>Thanks alot for the time you are investing in GRASS :)<br><br><br>Regards<br><br>Matthew<br><br><div><span class="gmail_quote">On 12/10/07, <b class="gmail_sendername">
Markus Neteler</b> <<a href="mailto:neteler@fbk.eu">neteler@fbk.eu</a>> wrote:</span><blockquote class="gmail_quote" style="margin-top: 0; margin-right: 0; margin-bottom: 0; margin-left: 0; margin-left: 0.80ex; border-left-color: #cccccc; border-left-width: 1px; border-left-style: solid; padding-left: 1ex">
<br>Matthew,<br><br>you can find the legend here:<br><a href="http://www.grassbook.org/data_menu3rd.php">http://www.grassbook.org/data_menu3rd.php</a><br>-> ncexternal/: NC original data set sources, metadata and copies of some
<br>original data<br> -> take metadata link<br> -> Streets.shp ... streets_wake_legend.csv<br><br>Most columns are explained there (as I could reconstruct them from the<br>original metadata<br>which you also find linked there (see "Data URL")).
<br><br>Hope this helps,<br>Markus<br><br><br>Yancho wrote:<br>><br>> Hi,<br>><br>> Whilst I am waiting for the book to arrive I have started playing a bit<br>> with<br>> the sample dataset of North Carolina. I am interested in the streets layer
<br>> (dataset) since basiclaly I am about to do some routing work.<br>><br>> Can someone please be kind enough to explain to me what do these columns<br>> represent?<br>><br>> frleft bigint,<br>> toleft bigint,
<br>> frright bigint,<br>> toright bigint,<br>> frleft_a bigint,<br>> toleft_a bigint,<br>> frright_a bigint,<br>> toright_a bigint,<br>> one_way character varying(80),<br>> ft_cost numeric,<br>> tf_cost numeric,
<br>> shape_len numeric,<br>> length double precision,<br>><br>> Also what is the difference between shape_len and length please?<br>><br>> My main concern are the one_ways and how I should treat them please.
<br>><br>> Any help will be extremely appreciated!<br>><br>> Regards<br>><br>> Matthew<br>><br>> --<br>> Matthew Pulis<br>> URL : <a href="http://www.solutions-lab.net">http://www.solutions-lab.net
</a><br>> MSN : pulis_matthew[@]hotmail.com<br>> ICQ : 145951110<br>> Skype : <a href="http://solutions-lab.net">solutions-lab.net</a><br>><br><br>--<br>View this message in context: <a href="http://www.nabble.com/3rd-Grass-Book-Data-Set-tp14242058p14244689.html">
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<br></blockquote></div><br><br clear="all"><br>-- <br>Matthew Pulis<br>URL : <a href="http://www.solutions-lab.net">http://www.solutions-lab.net</a><br>MSN : pulis_matthew[@]hotmail.com<br>ICQ : 145951110<br>Skype : <a href="http://solutions-lab.net">
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