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visits member for 1 year, 10 months
seen Dec 2 '13 at 15:17

Dec
2
comment Report Analysis Steps in ArcMap 10
thanks for your answer. Would be awesome if this was implemented.
Dec
2
comment Report Analysis Steps in ArcMap 10
Thanks for your hint! Code Snippets can be exported as phyton (right click in the results window on the tool). Still I dind't find any option to export all the steps automatically at once. So it's still a lot of manual work.
Nov
26
comment MMqgis (hub distance) error in distance
I have the same issue as mentioned above even when using a projected CRS. Can you explain a little more because when using ArcGIS it is perfectly possible to calculate distances with WGS84 World Mercator.
May
14
comment Built a query for polygon Shapefile in R
thanks for this summary!
May
13
comment Built a query for polygon Shapefile in R
thanks for the hint!
May
13
comment Built a query for polygon Shapefile in R
@JeffreyEvans all right. I edited it in the answer
May
12
comment Built a query for polygon Shapefile in R
@whuber you are right. Please note the edits in the answer to make it more comprehensive.
May
11
comment Create Raster file in R from Matrix and latlons
worked for me! thanks for the hint! I tried to work with the raster package too but got a bunch of complications, thats why I extracted the data without geoinformation. I had to rotate the matrix first like this : rotate1<-t(maize.anmean.1995.2004)and rotate2<-raster(rotate1[nrow(rotate1):1,]) in order to get the coordinates right. But than it worked smoothly!
May
10
comment Create Raster file in R from Matrix and latlons
@whuber I would like the output to be a raster yes, representing the data of the matrix. I thought of projection only in order to create the Raster as described in the post (see link above)
Mar
18
comment What could I do to make QGIS find all the plugins?
@Mapperz would you say it is better on MS?
Mar
7
comment Naming conventions PostGIS Database
@Paul Yeah it seems kind of mean I know ;) But from what i've expirienced so far, people only use what is usefull for them. The more usefull the more they use it and the more they use the better the metadata might get...The thing is that we don't have a person to take care of metadata so we need a participative approach where everybody contributes. the metadata document could maybe bring benefits too e.g. you could have better search and filter functions that allow to find more adequate data...but without a doubt I'm also thinking in alternative approaches to foster participation...
Mar
6
comment Naming conventions PostGIS Database
I really like the idea of categorizing the data and I will discuss this with my collegues. Still i'm not sure about naming the data inside the db. Your arguments make totally sense that for usability it will be bether to give clear names inside the db. But I fear that the metadata document may be less used like this. I thought that naming the data with abstract numbers would drive users to refer to the metadata document and with this contribute more to it in a way that people fill out more metadata information since they have to refer to it on a daily base and the document is already open...
Feb
8
comment Compare spatial cluster/agglomeration patterns for polygon data
what is the package called in R?
Feb
8
comment Compare spatial cluster/agglomeration patterns for polygon data
ok I think maybe HotSpot Analysis in ArcGIS might do the job...
Feb
8
comment Compare spatial cluster/agglomeration patterns for polygon data
I know some of these tools. I think they are basically designed for multivariate cluster-analysis. But in my case i would first like to see a univariate measurement of clusters. for point data it might be something similar to density analysis or hot spot analysis. But i don't know if there is anything similar for polygon data.
Jan
29
comment Self organizing maps and spatially Constrained Clustering in R
Skater is really adequate for this purpose. Thanks for the indication, I dind't knew it existed within R. Still I will have a carefull look if I can use this function, because skater only implements single linkage algorithms and my data is highly left skewed. That causes problems, so I'd prefer the ward algorithm or maybe partitioning algorithms. An alternative would be to use REDcap (spatialdatamining.org/software/redcap) wich works on the same principles as skater but comes along with Ward (unfortunatly outside of R...)
Jan
29
comment Self organizing maps and spatially Constrained Clustering in R
yes thats true. I already tried this out. Also with puting the x,y coordinates more than once I still don't get a hundret perent contigous regions... but how do you thing about implementing your idea in another way?
Jan
29
comment Self organizing maps and spatially Constrained Clustering in R
and is this any diffrent from simply attaching the coordinates of the polygon centroids (x,y) as variables to the dataframe that already contains the data used for clustering? its hard for me to understand theses questions...
Jan
29
comment Self organizing maps and spatially Constrained Clustering in R
Second: How would you implement your idea? do you simply put the spatial dissimilarities in the table of the other (statistical) dissimilarities? I have 771 objects, if I'd do it like that, my matrix would be enourmes and spatial distances could be overweighted...
Jan
29
comment Self organizing maps and spatially Constrained Clustering in R
Hi Spacedman. Thanks for your answer. Your idea seems very interessting to me. I was discussing this too with a collegue. I see two mayor challenges here. First i don't have homogenous polygons (it's not raster data but a shapefile from census regions). Extracting the coordinates of each polygon and creating a dissimilarity index will give me close distances for the small census regions and high distances for the large polygons. I fear that somehow this will affect my clustering analysis in the sense that first only the small regions will be clusterd.