Hec GeoRas Bank Layers Error

[srdatar]

Hello All,
I have hard time assigning line types in Hec GeoRas in ArcGIS 9.1
After Creating Stream CenterLine, Banks and Flow Path line layer, when I hit to select line type which is "Left Bank, Channel, or Right Bank" it gives some error and does not recognize bank layer. I tried all the snapping, editing tricks..is there any order in which I should creat layer, name them differently?

can any one help me?

Appreciate your time

sradatr

[WrTech]

Are you clicking on a Bank line using this tool? or are you clicking on a flow path line. The "Assign Line Type" tool assigns left, center and right labels to flow path lines, not the bank lines themselves.

If you open up the attribute table to the Flowpaths layer, you will see a column called Line Type. This is where the left, center and right designations go.

I hope this helps.

[srdatar]

WrTech

I was not really aware of this. I was creating flowpath layer by copying stream Center Line layer and then use to assign the line types for left bank, channel and right bank.

So what you saying is:
Create Stream Center Line Layer
Assign River ID to it
Create Bank Layer
Create Flow Path layer and instead of copying the Stream Center Line just draw the lines and using assign line types tool assign the Left, channel and Right,

let me try this.. lets see how it works.
Appreciate your help and time in this regard.

srdatar

[WrTech]

When GeoRas prompts you to use the Stream layer as the Flowpath center line you can click yes, that shouldn't give you any problems. You will still have to draw two additional flowpath lines that delineate the approximate center of mass of the floodplain in the over bank areas. It is these two lines that will be labeled Left or right.

If you want a quick and easy solution, you can copy and paste the bank lines into the flow path layer. However, I've seen that often the banks of a stream do not coincide with the center of mass of a flood event.

[srdatar]

WrTech

Thanks for your help. It seems that you have pretty good hand on Hec GeoRas and I have just started playing with it.

I will try it tonight and will see how it goes. Infact I do have one more query of getting the data in proper format.

Could you just explain me lil bit how you process data and from where you get raw data from?

I just get Dem shape files on MARIS (for mississippi) site and convert these to raster, and build tin but i don't know this is the right way to do it.. or do we have to get it from USGS seamless..?

Thanks a zillion

Srdatar

[WrTech]

Ah, my friend. I am but a simple Technician, I'm not familiar with a lot of the GIS data wizardry and mumbo jumbo. My data is supplied to me by my resident GIS guru and I simply generate Tins from the data as needed.

I can tell you that we have 10m point data and detailed breaklines for our entire watershed which was paid for by the organization that I work for.

I would suggest that you find the best data for your area that you possibly can and use that. I'm not familiar with the American system, but if there are local agency's in Mississippi that deal with flood forecasting, they might have good elevation and breakline data that they might let you use.

[srdatar]

Mr. Tech
thanks for your reply..

thanks for all the help.


srdatar