[GRASS-user] Stream order for vector networks

GRASS GRASS user
1

Hi,

I am interested in calculating stream order (Strahler, Shreve) for stream networks based on GRASS vector networks (e.g. created by v.net) without using the raster approach of the GRASS add-on r.stream.order. Therefore, I came across following paper:

Gleyzer, A., Denisyuk, M., Rimmer, A. and Salingar, Y. (2004), A FAST RECURSIVE GIS ALGORITHM FOR COMPUTING STRAHLER STREAM ORDER IN BRAIDED AND NONBRAIDED NETWORKS. JAWRA Journal of the American Water Resources Association, 40: 937–946. doi: 10.1111/j.1752-1688.2004.tb01057.x

which also provides pseudocode to calculate Strahler order for non-braided and braided vector networks defined by arcs and nodes. Thus, I am wondering if it is possible to get the information from which node a specific arc starts (from_node) and where it drains to (to_node). BTW, I seems some kind of this information is already provided with the NC-dataset (FNODE_ and TNODE column) in the streams attribute table, however I don’t know where this information comes from. Of course to extract this information the network needs to be directed to define what is the upstream and what the downstream node of each arc. However, having this information available, it should not be to complicated to apply the algorithm proposed by Gleyzer et al 2004. Thus I am interested to get ‘from_node’ and ‘to_node’ information e.g. stored in the attribute table of v.net output?

Here the pseudocode provided by Gleyzer et al 2004:

########################################################################

MakeDictionaries(Network)
1 for each Arc ∈ Network
2 do FromNodesPerArc[Arc’s ID] ← Arc’s FromNodeID
3 InflowingArcsPerNode[Arc’s ToNodeID] ← InflowingArcsPerNode[Arc’s ToNodeID] ∪ Arc’s ID
4 OriginatingNode[Arc’s ID] ← Arc’s FromNodeID

StreamOrdering(ArcID)
1 Visited[ArcID] ← true
2 if | InflowingArcsPerNode[ FromNodesPerArc[ArcID] ] | = 0
3 then StreamOrders[ArcID] ← 1
4 else
5 for each Arc ∈ InflowingArcsPerNode[ FromNodesPerArc[ArcID] ]
6 do if not Visited[Arc]
7 then UpstreamOrders[Arc] ← (StreamOrdering(Arc), OriginatingNode[Arc])
8 else UpstreamOrders[Arc] ← (StreamOrders[Arc], OriginatingNode[Arc])
9 MaxOrder ← 0
10 MaxOrderCount ← 0
11 for each (Order, Origin) ∈ UpstreamOrders
12 do if Order > MaxOrder
13 then MaxOrder ← Order
14 MaxOrderCount ← 1
15 MaxOrderOrigin ← Origin
16 else if Order = MaxOrder
17 then if Origin ≠ MaxOrderOrigin
18 then MaxOrderCount ← MaxOrderCount + 1
19 if MaxOrderCount > 1
20 then StreamOrders[ArcID] ← MaxOrder + 1
21 OriginatingNode[ArcID] ← FromNodesPerArc[ArcID]
22 else StreamOrders[ArcID] ← MaxOrder
23 OriginatingNode[ArcID] ← MaxOrderOrigin
24 if SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ] = nil
25 then SegmentIDs[ StreamOrders[ArcID] ] ← SegmentIDs[ StreamOrders[ArcID] ] + 1
26 SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ] ← SegmentIDs[ StreamOrders[ArcID] ]
27 Segments[ArcID] ← SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ]
28 return StreamOrders[ArcID]

########################################################################

Is there anyone having experience with that, or has already tried to implement a vector-stream order approach in GRASS GIS. Specifically I am interested
in Shreve stream order for simple (non-braided) stream networks and Strahler stream order for braided river networks (Gleyzer et al 2004).

Best regards,
Johannes

2

Hi Johannes,

For more complex network analysis I can warmly recommend the igraph package (http://igraph.org/, which has both Python and R bindings).

It comes very handy for customized network analysis, is not too complicated to learn, well documented and quite efficient.

I could provide you with some sample code in R if that would be of interest.

Cheers

Stefan

···

Hi,

I am interested in calculating stream order (Strahler, Shreve) for stream networks based on GRASS vector networks (e.g. created by v.net) without using the raster approach of the GRASS add-on r.stream.order. Therefore, I came across following paper:

Gleyzer, A., Denisyuk, M., Rimmer, A. and Salingar, Y. (2004), A FAST RECURSIVE GIS ALGORITHM FOR COMPUTING STRAHLER STREAM ORDER IN BRAIDED AND NONBRAIDED NETWORKS. JAWRA Journal of the American Water Resources Association, 40: 937–946. doi: 10.1111/j.1752-1688.2004.tb01057.x

which also provides pseudocode to calculate Strahler order for non-braided and braided vector networks defined by arcs and nodes. Thus, I am wondering if it is possible to get the information from which node a specific arc starts (from_node) and where it drains to (to_node). BTW, I seems some kind of this information is already provided with the NC-dataset (FNODE_ and TNODE column) in the streams attribute table, however I don’t know where this information comes from. Of course to extract this information the network needs to be directed to define what is the upstream and what the downstream node of each arc. However, having this information available, it should not be to complicated to apply the algorithm proposed by Gleyzer et al 2004. Thus I am interested to get ‘from_node’ and ‘to_node’ information e.g. stored in the attribute table of v.net output?

Here the pseudocode provided by Gleyzer et al 2004:

########################################################################

MakeDictionaries(Network)

1 for each Arc ∈ Network

2 do FromNodesPerArc[Arc’s ID] ← Arc’s FromNodeID

3 InflowingArcsPerNode[Arc’s ToNodeID] ← InflowingArcsPerNode[Arc’s ToNodeID] ∪ Arc’s ID

4 OriginatingNode[Arc’s ID] ← Arc’s FromNodeID

StreamOrdering(ArcID)

1 Visited[ArcID] ← true

2 if | InflowingArcsPerNode[ FromNodesPerArc[ArcID] ] | = 0

3 then StreamOrders[ArcID] ← 1

4 else

5 for each Arc ∈ InflowingArcsPerNode[ FromNodesPerArc[ArcID] ]

6 do if not Visited[Arc]

7 then UpstreamOrders[Arc] ← (StreamOrdering(Arc), OriginatingNode[Arc])

8 else UpstreamOrders[Arc] ← (StreamOrders[Arc], OriginatingNode[Arc])

9 MaxOrder ← 0

10 MaxOrderCount ← 0

11 for each (Order, Origin) ∈ UpstreamOrders

12 do if Order > MaxOrder

13 then MaxOrder ← Order

14 MaxOrderCount ← 1

15 MaxOrderOrigin ← Origin

16 else if Order = MaxOrder

17 then if Origin ≠ MaxOrderOrigin

18 then MaxOrderCount ← MaxOrderCount + 1

19 if MaxOrderCount > 1

20 then StreamOrders[ArcID] ← MaxOrder + 1

21 OriginatingNode[ArcID] ← FromNodesPerArc[ArcID]

22 else StreamOrders[ArcID] ← MaxOrder

23 OriginatingNode[ArcID] ← MaxOrderOrigin

24 if SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ] = nil

25 then SegmentIDs[ StreamOrders[ArcID] ] ← SegmentIDs[ StreamOrders[ArcID] ] + 1

26 SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ] ← SegmentIDs[ StreamOrders[ArcID] ]

27 Segments[ArcID] ← SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ]

28 return StreamOrders[ArcID]

########################################################################

Is there anyone having experience with that, or has already tried to implement a vector-stream order approach in GRASS GIS. Specifically I am interested

in Shreve stream order for simple (non-braided) stream networks and Strahler stream order for braided river networks (Gleyzer et al 2004).

Best regards,

Johannes

3

Stefan,
thanks for your recommendation of the igraph-package. This would make indeed sense for more complex analysis.

At the moment I am just interested in an GRASS (native) way to get a stream order for a vector network. For this, purpose, and I guess also for using the igraph package, one needs the information of the start (from_node) and endnode (to_node) of each arc. So I am still looking how this information can be extracted in GRASS and e.g. written into the attribute table?!

Best regards,
Johannes

···

On Wed, Mar 18, 2015 at 10:43 AM, Blumentrath, Stefan <Stefan.Blumentrath@nina.no> wrote:

Hi Johannes,

For more complex network analysis I can warmly recommend the igraph package (http://igraph.org/, which has both Python and R bindings).

It comes very handy for customized network analysis, is not too complicated to learn, well documented and quite efficient.

I could provide you with some sample code in R if that would be of interest.

Cheers

Stefan

From: grass-user-bounces@lists.osgeo.org [mailto:grass-user-bounces@lists.osgeo.org] On Behalf Of Johannes Radinger
Sent: 18. mars 2015 10:30
To: GRASS user list
Subject: [GRASS-user] Stream order for vector networks

Hi,

I am interested in calculating stream order (Strahler, Shreve) for stream networks based on GRASS vector networks (e.g. created by v.net) without using the raster approach of the GRASS add-on r.stream.order. Therefore, I came across following paper:

Gleyzer, A., Denisyuk, M., Rimmer, A. and Salingar, Y. (2004), A FAST RECURSIVE GIS ALGORITHM FOR COMPUTING STRAHLER STREAM ORDER IN BRAIDED AND NONBRAIDED NETWORKS. JAWRA Journal of the American Water Resources Association, 40: 937–946. doi: 10.1111/j.1752-1688.2004.tb01057.x

which also provides pseudocode to calculate Strahler order for non-braided and braided vector networks defined by arcs and nodes. Thus, I am wondering if it is possible to get the information from which node a specific arc starts (from_node) and where it drains to (to_node). BTW, I seems some kind of this information is already provided with the NC-dataset (FNODE_ and TNODE column) in the streams attribute table, however I don’t know where this information comes from. Of course to extract this information the network needs to be directed to define what is the upstream and what the downstream node of each arc. However, having this information available, it should not be to complicated to apply the algorithm proposed by Gleyzer et al 2004. Thus I am interested to get ‘from_node’ and ‘to_node’ information e.g. stored in the attribute table of v.net output?

Here the pseudocode provided by Gleyzer et al 2004:

########################################################################

MakeDictionaries(Network)

1 for each Arc ∈ Network

2 do FromNodesPerArc[Arc’s ID] ← Arc’s FromNodeID

3 InflowingArcsPerNode[Arc’s ToNodeID] ← InflowingArcsPerNode[Arc’s ToNodeID] ∪ Arc’s ID

4 OriginatingNode[Arc’s ID] ← Arc’s FromNodeID

StreamOrdering(ArcID)

1 Visited[ArcID] ← true

2 if | InflowingArcsPerNode[ FromNodesPerArc[ArcID] ] | = 0

3 then StreamOrders[ArcID] ← 1

4 else

5 for each Arc ∈ InflowingArcsPerNode[ FromNodesPerArc[ArcID] ]

6 do if not Visited[Arc]

7 then UpstreamOrders[Arc] ← (StreamOrdering(Arc), OriginatingNode[Arc])

8 else UpstreamOrders[Arc] ← (StreamOrders[Arc], OriginatingNode[Arc])

9 MaxOrder ← 0

10 MaxOrderCount ← 0

11 for each (Order, Origin) ∈ UpstreamOrders

12 do if Order > MaxOrder

13 then MaxOrder ← Order

14 MaxOrderCount ← 1

15 MaxOrderOrigin ← Origin

16 else if Order = MaxOrder

17 then if Origin ≠ MaxOrderOrigin

18 then MaxOrderCount ← MaxOrderCount + 1

19 if MaxOrderCount > 1

20 then StreamOrders[ArcID] ← MaxOrder + 1

21 OriginatingNode[ArcID] ← FromNodesPerArc[ArcID]

22 else StreamOrders[ArcID] ← MaxOrder

23 OriginatingNode[ArcID] ← MaxOrderOrigin

24 if SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ] = nil

25 then SegmentIDs[ StreamOrders[ArcID] ] ← SegmentIDs[ StreamOrders[ArcID] ] + 1

26 SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ] ← SegmentIDs[ StreamOrders[ArcID] ]

27 Segments[ArcID] ← SegmentIDsPerOriginatingNode[ OriginatingNode[ArcID] ]

28 return StreamOrders[ArcID]

########################################################################

Is there anyone having experience with that, or has already tried to implement a vector-stream order approach in GRASS GIS. Specifically I am interested

in Shreve stream order for simple (non-braided) stream networks and Strahler stream order for braided river networks (Gleyzer et al 2004).

Best regards,

Johannes

4

At the moment I am just interested in an GRASS (native) way to get a stream

order for a vector network.

maybe http://grasswiki.osgeo.org/wiki/AddOns/GRASS_6#v.strahler could be a
starting point?

-----
best regards
Helmut
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