Clustering points and summing up attributes per cluster in QGIS
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We want to find out the ideal location for sheds and the required dimensions of each shed. As input, we have a point layer with locations (each representing one arable field) and the estimated yield per point (per arable field).
What we now try to do is first to create four clusters for these fields. This should serve as an approximation of the ideal location for a new shed. We've done this by simply using the "point cluster" option in the "symbology" section and adjusting the distance until only four cluster points remained. These cluster points were then saved as new point shapefile.
How do we determine what points are actually clustered in each of the cluster points?
With this information, we can then sum up the estimated yields for all the single points per cluster. This would allow us to calculate whether the shed has to be designed for 10 tons or 100 tons of grain.
qgis clustering connectivity-analysis
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
asked Mar 29 at 7:20
cbrcbr
454
add a comment |
We want to find out the ideal location for sheds and the required dimensions of each shed. As input, we have a point layer with locations (each representing one arable field) and the estimated yield per point (per arable field).
What we now try to do is first to create four clusters for these fields. This should serve as an approximation of the ideal location for a new shed. We've done this by simply using the "point cluster" option in the "symbology" section and adjusting the distance until only four cluster points remained. These cluster points were then saved as new point shapefile.
How do we determine what points are actually clustered in each of the cluster points?
With this information, we can then sum up the estimated yields for all the single points per cluster. This would allow us to calculate whether the shed has to be designed for 10 tons or 100 tons of grain.
qgis clustering connectivity-analysis
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
asked Mar 29 at 7:20
cbrcbr
454
add a comment |
We want to find out the ideal location for sheds and the required dimensions of each shed. As input, we have a point layer with locations (each representing one arable field) and the estimated yield per point (per arable field).
What we now try to do is first to create four clusters for these fields. This should serve as an approximation of the ideal location for a new shed. We've done this by simply using the "point cluster" option in the "symbology" section and adjusting the distance until only four cluster points remained. These cluster points were then saved as new point shapefile.
How do we determine what points are actually clustered in each of the cluster points?
With this information, we can then sum up the estimated yields for all the single points per cluster. This would allow us to calculate whether the shed has to be designed for 10 tons or 100 tons of grain.
qgis clustering connectivity-analysis
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
asked Mar 29 at 7:20
cbrcbr
454
We want to find out the ideal location for sheds and the required dimensions of each shed. As input, we have a point layer with locations (each representing one arable field) and the estimated yield per point (per arable field).
What we now try to do is first to create four clusters for these fields. This should serve as an approximation of the ideal location for a new shed. We've done this by simply using the "point cluster" option in the "symbology" section and adjusting the distance until only four cluster points remained. These cluster points were then saved as new point shapefile.
How do we determine what points are actually clustered in each of the cluster points?
With this information, we can then sum up the estimated yields for all the single points per cluster. This would allow us to calculate whether the shed has to be designed for 10 tons or 100 tons of grain.
qgis clustering connectivity-analysis
qgis clustering connectivity-analysis
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
asked Mar 29 at 7:20
cbrcbr
454
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
asked Mar 29 at 7:20
cbrcbr
454
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
edited Mar 30 at 0:39
PolyGeo♦
53.9k1782246
53.9k1782246
asked Mar 29 at 7:20
cbrcbr
454
asked Mar 29 at 7:20
cbrcbr
454
asked Mar 29 at 7:20
cbrcbr
454
454
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
I would try K-means clustering algorithm in the QGIS Processing Toolbox (under Vector analysis group).
Just by setting the Number of clusters as 4, it will produce a new Clusters layer with an attribute field CLUSTER_ID (values= 0, 1, 2, 3).
Then an expression like SUM("yield", "CLUSTER_ID") in the Field Calculator will return the total yield for each cluster. (E.G. the Sum_per_Cluster in the below example).
[Update]
To obtain center point per the group (cluster), please try Mean coordinate(s) geoalgorithm in Processing Toolbox > Vector analysis.
Mean coordinates dialog window will show an option Unique ID field. Select CLUSTER_ID field.
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using"Symbology"and"Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!
– cbr
Mar 29 at 14:16
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
@cbr To create center point for each cluster, please useCentroidsgeoalgorithm. I will update my post. As to the center points (red circles) in my example, they werePoint clustersymbology just for comparison.
– Kazuhito
Mar 29 at 21:47
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
Thanks very much for your reply! Thecentroidsalgorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?
– cbr
Mar 30 at 7:33
|
show 5 more comments
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I would try K-means clustering algorithm in the QGIS Processing Toolbox (under Vector analysis group).
Just by setting the Number of clusters as 4, it will produce a new Clusters layer with an attribute field CLUSTER_ID (values= 0, 1, 2, 3).
Then an expression like SUM("yield", "CLUSTER_ID") in the Field Calculator will return the total yield for each cluster. (E.G. the Sum_per_Cluster in the below example).
[Update]
To obtain center point per the group (cluster), please try Mean coordinate(s) geoalgorithm in Processing Toolbox > Vector analysis.
Mean coordinates dialog window will show an option Unique ID field. Select CLUSTER_ID field.
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using"Symbology"and"Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!
– cbr
Mar 29 at 14:16
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
@cbr To create center point for each cluster, please useCentroidsgeoalgorithm. I will update my post. As to the center points (red circles) in my example, they werePoint clustersymbology just for comparison.
– Kazuhito
Mar 29 at 21:47
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
Thanks very much for your reply! Thecentroidsalgorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?
– cbr
Mar 30 at 7:33
|
show 5 more comments
I would try K-means clustering algorithm in the QGIS Processing Toolbox (under Vector analysis group).
Just by setting the Number of clusters as 4, it will produce a new Clusters layer with an attribute field CLUSTER_ID (values= 0, 1, 2, 3).
Then an expression like SUM("yield", "CLUSTER_ID") in the Field Calculator will return the total yield for each cluster. (E.G. the Sum_per_Cluster in the below example).
[Update]
To obtain center point per the group (cluster), please try Mean coordinate(s) geoalgorithm in Processing Toolbox > Vector analysis.
Mean coordinates dialog window will show an option Unique ID field. Select CLUSTER_ID field.
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using"Symbology"and"Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!
– cbr
Mar 29 at 14:16
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
@cbr To create center point for each cluster, please useCentroidsgeoalgorithm. I will update my post. As to the center points (red circles) in my example, they werePoint clustersymbology just for comparison.
– Kazuhito
Mar 29 at 21:47
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
Thanks very much for your reply! Thecentroidsalgorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?
– cbr
Mar 30 at 7:33
|
show 5 more comments
I would try K-means clustering algorithm in the QGIS Processing Toolbox (under Vector analysis group).
Just by setting the Number of clusters as 4, it will produce a new Clusters layer with an attribute field CLUSTER_ID (values= 0, 1, 2, 3).
Then an expression like SUM("yield", "CLUSTER_ID") in the Field Calculator will return the total yield for each cluster. (E.G. the Sum_per_Cluster in the below example).
[Update]
To obtain center point per the group (cluster), please try Mean coordinate(s) geoalgorithm in Processing Toolbox > Vector analysis.
Mean coordinates dialog window will show an option Unique ID field. Select CLUSTER_ID field.
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
I would try K-means clustering algorithm in the QGIS Processing Toolbox (under Vector analysis group).
Just by setting the Number of clusters as 4, it will produce a new Clusters layer with an attribute field CLUSTER_ID (values= 0, 1, 2, 3).
Then an expression like SUM("yield", "CLUSTER_ID") in the Field Calculator will return the total yield for each cluster. (E.G. the Sum_per_Cluster in the below example).
[Update]
To obtain center point per the group (cluster), please try Mean coordinate(s) geoalgorithm in Processing Toolbox > Vector analysis.
Mean coordinates dialog window will show an option Unique ID field. Select CLUSTER_ID field.
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
edited Mar 30 at 21:36
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
answered Mar 29 at 8:43
KazuhitoKazuhito
16.4k41884
16.4k41884
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using"Symbology"and"Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!
– cbr
Mar 29 at 14:16
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
@cbr To create center point for each cluster, please useCentroidsgeoalgorithm. I will update my post. As to the center points (red circles) in my example, they werePoint clustersymbology just for comparison.
– Kazuhito
Mar 29 at 21:47
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
Thanks very much for your reply! Thecentroidsalgorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?
– cbr
Mar 30 at 7:33
|
show 5 more comments
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using"Symbology"and"Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!
– cbr
Mar 29 at 14:16
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
@cbr To create center point for each cluster, please useCentroidsgeoalgorithm. I will update my post. As to the center points (red circles) in my example, they werePoint clustersymbology just for comparison.
– Kazuhito
Mar 29 at 21:47
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
Thanks very much for your reply! Thecentroidsalgorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?
– cbr
Mar 30 at 7:33
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using
"Symbology" and "Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!– cbr
Mar 29 at 14:16
Thank you very much for the quick and helpful reply! How did you create the center points of the clusters? When I use the method I described in my initial post (using
"Symbology" and "Cluster"), I get center points completely off the actual cluster center (see [ibb.co/VmkhS0x]). This may stem from the different calculation methods. What approach did you use in your example? Furthermore, I get a lot of "NULL" results when I do the K-means clustering (see [ibb.co/VNdQ7bS]). Do you have a solution for this issue? Thank you very much!– cbr
Mar 29 at 14:16
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
Since I only get error pages when trying to access the uploaded images but cannot edit the comment anymore (>5 min), here other links: Cluster center -> imgur.com/a/fs3R1K1 ; NULL -> imgur.com/a/Cv7IuCr
– cbr
Mar 29 at 14:23
@cbr To create center point for each cluster, please use
Centroids geoalgorithm. I will update my post. As to the center points (red circles) in my example, they were Point cluster symbology just for comparison.– Kazuhito
Mar 29 at 21:47
@cbr To create center point for each cluster, please use
Centroids geoalgorithm. I will update my post. As to the center points (red circles) in my example, they were Point cluster symbology just for comparison.– Kazuhito
Mar 29 at 21:47
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
@cbr Your upperleft (north western) cluster in the provided image has only two locations in that cluster, which does not seem right. (You would not build shed just for those two). I am not sure what happened with locations with NULL outputs; they may be outliers. Perhaps I would check their locations visually, and manually assign most appropriate cluster id.
– Kazuhito
Mar 29 at 22:03
Thanks very much for your reply! The
centroids algorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?– cbr
Mar 30 at 7:33
Thanks very much for your reply! The
centroids algorithm only returns the same location for each of the selected points (so the output is a layer with the same amount of points as the input layer). I assume that the center point for each point was calculated but not one single point for the whole cluster... Is there another intermediate step necessary I made have missed?– cbr
Mar 30 at 7:33
|
show 5 more comments
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