topic Re: Location Allocation (minimize facilities) providing strange results in ArcGIS Network Analyst Questions https://community.esri.com/t5/arcgis-network-analyst-questions/location-allocation-minimize-facilities-providing/m-p/566866#M5465 <HTML><HEAD></HEAD><BODY><BLOCKQUOTE class="jive-quote">I am trying to identify the minimum number of stations using the Location-Allocation minimize stations function.&nbsp; I have 710 potential locations and roughly 40,000 demand points.&nbsp; Based on the street speed limits, and the size of the area, I believe that all of the demand points could be reached by 7-9 stations within 4 minutes, and 4-5 stations in 8 minutes (just <BR />eyeballing it based on previous service area maps).&nbsp; <BR /><BR />However, when I run the minimize facilities problem type using a 4 minute impedance in the location allocation tool, the results show approximately 21 stations, and many are within a thousand feet of each other.&nbsp; There are only two settings: the impedance cut-off&nbsp; (I'm using 4) and the impedance transformation (I'm using linear), am I doing this incorrectly?&nbsp; <BR /><BR />Any advice would be much appreciated, I've been working on this for a couple of days with much aggravation.</BLOCKQUOTE><BR /><SPAN> </SPAN><BR /><SPAN>You may have a disconnected network meaning that edges are not connected even though they look connected when you draw the network.&nbsp; Can you route between the chosen facilities that are next to each other?</SPAN><BR /><BR /><SPAN>You may have a combination of restrictions that result in a disconnected network.&nbsp; Try resolving without any restrictions.</SPAN><BR /><BR /><SPAN>If you are using hierarchy then you may have incorrect hierarchy values.&nbsp; Try solving without hierarchy.</SPAN><BR /><BR /><SPAN>Your impedance cutoff of 4 may not be what you are expecting.&nbsp; The impedance cutoff has the same units as the impedance attribute.&nbsp; Make sure a value of 4 makes sense in light of your impedance attribute (which I assume is in minutes).</SPAN><BR /><BR /><SPAN>You may have accidentally added your stations to your network dataset as a junction source and your points are locating on them but they are disconnected from all edges in the graph.&nbsp; Make sure that when you are locating your stations that you are locating only on your edges, not junctions.</SPAN><BR /><BR /><SPAN>Hope this helps.&nbsp; The location-allocation solver should work in the way that you expect.</SPAN><BR /><BR /><SPAN>Doug</SPAN></BODY></HTML> Thu, 16 Feb 2012 14:55:33 GMT DougSterling 2012-02-16T14:55:33Z Location Allocation (minimize facilities) providing strange results https://community.esri.com/t5/arcgis-network-analyst-questions/location-allocation-minimize-facilities-providing/m-p/566865#M5464 <HTML><HEAD></HEAD><BODY><SPAN>I am trying to identify the minimum number of stations using the Location-Allocation minimize stations function.&nbsp; I have 710 potential locations and roughly 40,000 demand points.&nbsp; Based on the street speed limits, and the size of the area, I believe that all of the demand points could be reached by 7-9 stations within 4 minutes, and 4-5 stations in 8 minutes (just </SPAN><BR /><SPAN>eyeballing it based on previous service area maps).&nbsp; </SPAN><BR /><BR /><SPAN>However, when I run the minimize facilities problem type using a 4 minute impedance in the location allocation tool, the results show approximately 21 stations, and many are within a thousand feet of each other.&nbsp; There are only two settings: the impedance cut-off&nbsp; (I'm using 4) and the impedance transformation (I'm using linear), am I doing this incorrectly?&nbsp; </SPAN><BR /><BR /><SPAN>Any advice would be much appreciated, I've been working on this for a couple of days with much aggravation.</SPAN></BODY></HTML> Wed, 15 Feb 2012 13:36:49 GMT https://community.esri.com/t5/arcgis-network-analyst-questions/location-allocation-minimize-facilities-providing/m-p/566865#M5464 justinhampton 2012-02-15T13:36:49Z Re: Location Allocation (minimize facilities) providing strange results https://community.esri.com/t5/arcgis-network-analyst-questions/location-allocation-minimize-facilities-providing/m-p/566866#M5465 <HTML><HEAD></HEAD><BODY><BLOCKQUOTE class="jive-quote">I am trying to identify the minimum number of stations using the Location-Allocation minimize stations function.&nbsp; I have 710 potential locations and roughly 40,000 demand points.&nbsp; Based on the street speed limits, and the size of the area, I believe that all of the demand points could be reached by 7-9 stations within 4 minutes, and 4-5 stations in 8 minutes (just <BR />eyeballing it based on previous service area maps).&nbsp; <BR /><BR />However, when I run the minimize facilities problem type using a 4 minute impedance in the location allocation tool, the results show approximately 21 stations, and many are within a thousand feet of each other.&nbsp; There are only two settings: the impedance cut-off&nbsp; (I'm using 4) and the impedance transformation (I'm using linear), am I doing this incorrectly?&nbsp; <BR /><BR />Any advice would be much appreciated, I've been working on this for a couple of days with much aggravation.</BLOCKQUOTE><BR /><SPAN> </SPAN><BR /><SPAN>You may have a disconnected network meaning that edges are not connected even though they look connected when you draw the network.&nbsp; Can you route between the chosen facilities that are next to each other?</SPAN><BR /><BR /><SPAN>You may have a combination of restrictions that result in a disconnected network.&nbsp; Try resolving without any restrictions.</SPAN><BR /><BR /><SPAN>If you are using hierarchy then you may have incorrect hierarchy values.&nbsp; Try solving without hierarchy.</SPAN><BR /><BR /><SPAN>Your impedance cutoff of 4 may not be what you are expecting.&nbsp; The impedance cutoff has the same units as the impedance attribute.&nbsp; Make sure a value of 4 makes sense in light of your impedance attribute (which I assume is in minutes).</SPAN><BR /><BR /><SPAN>You may have accidentally added your stations to your network dataset as a junction source and your points are locating on them but they are disconnected from all edges in the graph.&nbsp; Make sure that when you are locating your stations that you are locating only on your edges, not junctions.</SPAN><BR /><BR /><SPAN>Hope this helps.&nbsp; The location-allocation solver should work in the way that you expect.</SPAN><BR /><BR /><SPAN>Doug</SPAN></BODY></HTML> Thu, 16 Feb 2012 14:55:33 GMT https://community.esri.com/t5/arcgis-network-analyst-questions/location-allocation-minimize-facilities-providing/m-p/566866#M5465 DougSterling 2012-02-16T14:55:33Z