I'm new to ArcGIS programming and looking for some assistance here. We are running ArcGIS 10.1 server, Spacial Analysis for Raster Layers, and the 2500 version of ArcGIS explorer.

We are using a boats' area of responsibility as a limiter for the distance it can respond to issues for 15 minute segments out to 90 minutes. Today our response vectors are just running the boat flat out at full speed without any external influences. This may be fine where the AOR is on the ocean, but not good in rivers. We pass a value which is the distance covered in each segment of time minus the time it takes for the crew to initially respond based on day or nighttime events.

We need to be able to take into account no wake zones, speed limits, and the possibility that a barge is blocking the path and needs to be carefully passed before returning to full speed.

The current server code does generate a raster (I assume this is the full area of response) passing the values for the 6 segments. Then they create a cost array (and I believe this is where I inject the speed limits, blockages, etc) and then do the final call to get the polygons to draw.

So I wondering how to set up this cost array so that the values act as speed limiters on the process. So showing below:

Max speed 46 knots

Distance covered in 15 minutes

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

| 20 knot limit |

Final vector (source raster array with speed limit applied in cost raster array) should be

xxxxxxxxxxxxxxxxxxxxxxx

Since the two arrays are added together do I set the cost array to -26 for that area? The documentation only talks of positive values in the cost array.

Thanks for any assistance anyone can provide.

Michael

We are using a boats' area of responsibility as a limiter for the distance it can respond to issues for 15 minute segments out to 90 minutes. Today our response vectors are just running the boat flat out at full speed without any external influences. This may be fine where the AOR is on the ocean, but not good in rivers. We pass a value which is the distance covered in each segment of time minus the time it takes for the crew to initially respond based on day or nighttime events.

We need to be able to take into account no wake zones, speed limits, and the possibility that a barge is blocking the path and needs to be carefully passed before returning to full speed.

The current server code does generate a raster (I assume this is the full area of response) passing the values for the 6 segments. Then they create a cost array (and I believe this is where I inject the speed limits, blockages, etc) and then do the final call to get the polygons to draw.

So I wondering how to set up this cost array so that the values act as speed limiters on the process. So showing below:

Max speed 46 knots

Distance covered in 15 minutes

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

| 20 knot limit |

Final vector (source raster array with speed limit applied in cost raster array) should be

xxxxxxxxxxxxxxxxxxxxxxx

Since the two arrays are added together do I set the cost array to -26 for that area? The documentation only talks of positive values in the cost array.

Thanks for any assistance anyone can provide.

Michael

If I understand you correctly you want to setup a cost raster to include speed. Performing a cost distance calculation is not more than a normal distance calculation where the distance is converted to travel cost. It is possible to obtain travel times if the cost raster represents the number of time units per distance unit (inverse speed).

Let�??s say you are working with a raster resolution of 100m. For a certain cell "A" the speed is 46 knots. 46 knots is about 23.7 m/s. The cost of that cell shout be 1/23.7 (s/m). When traveling horizontally or vertically over that cell the distance (100m) will be multiplied by the cost (1/23.7), which is results in around 4.2 seconds. So, it will take 4.2 seconds to travel over that cell.

For those cells that have a different max speed like 20 knots, the cost raster will have a different (higher) value, since the "costs" is higher to travel over that cell. 20kn * 0.514444 = 10.3m/s. The cost will be 1/10.3 (s/m). Travel over this cell horizontally or vertically will take 100m*1/10.3s/m = 9.7 seconds.

After the cost distance calculation you can reclassify your raster in the time zones needed.

More info on how cost distance works:

http://resources.arcgis.com/en/help/main/10.1/index.html#/How_the_cost_distance_tools_work/009z00000025000000/

Kind regards,

Xander