Re: [GRASS-user] Linking multidimensional data to a single point
On Mon, Mar 16, 2015 at 9:07 PM, Rich Shepard rshep...@appl-ecosys.com wrote: On Sun, 15 Mar 2015, Paulo van Breugel wrote: The attribute table is in a sqlite table already, unless you are still using dbf as database backend for grass. Just link your other tables to that attribute table? Paulo, Thanks for reminding us. I forgot about that. You are correct that the thing to do is link the other tables to that attribute table. Rich Thanks Paulo and Rich, So would this be adding additional SQL database tables as additional layers associated with a GRASS GIS vector data set? I had thought that the layers also needed to be linked to vector points... so I'm guessing that this would still be linking outside SQL tables to the GRASS table? Thinking out loud and putting my reasoning in an email in case someone seeing this conversation is helped by this later. Andy ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
On Mon, 16 Mar 2015, Andy Wickert wrote: So would this be adding additional SQL database tables as additional layers associated with a GRASS GIS vector data set? I had thought that the layers also needed to be linked to vector points... so I'm guessing that this would still be linking outside SQL tables to the GRASS table? Andy, Nope. Additional tables to the same map/layer. You have a map of data collection locations. Perhaps you have other layers/coverages of roads, land use/land cover, even a raster of the terrain (based on a DEM). To any of these layers you can have as many relational database tables as is appropriate to the chunks of data you have associated with each feature on a single layer. You are adding attribute data to each point on your one map. That's done behind the scenes in SQLite and is not visible on the map. Depending on your use of this application, you might use the discharge or sediment composition data to procues heat maps of intensities, or do other kewel stuff with your data, but you'll probably end up analyzing your data with R and producing spiffy plots to accompany the spatial analyses you run. Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
Rich Shepard rshep...@appl-ecosys.com schreef op 15 maart 2015 23:49:06 CET: On Sun, 15 Mar 2015, Andy Wickert wrote: So to boil it down to the simplest part of what you said, the key is just to have an ID column in the GRASS table that links to a table in a database structure outside of GRASS? Andy, Yes. You can keep all point attributes in SQLite (or other rdbms) tables rather than in GRASS. The attribute table is in a sqlite table already, unless you are still using dbf as database backend for grass. Just link your other tables to that attribute table? It's been a while since I last did this so the specifics are not immediately available. I would link each point to a table which describes it; perhaps including geographic coordinates, name, and other information. Then your discharge and sediment data are in other tables that are related to each row in the main table. This also allows you to run SQL queries on the data (such as descriptice statistics) outside of GRASS. Just to make sure that I was clear: the problem is how to include multiple rows of data that all correspond to just one point in GIS (so grain size with frequencies in each grain size class or discharge with discharges at different times). Database design is a topic of itself. Separate attribute data from the spatial data; the former goes into a database (multiple tables), the latter in GRASS files. In your initial message you describe three different categories of data and each should be in its own table. Information about each data collection point (which is seen on the map) is in one table. This could include a site ID as the primary key, site name, perhaps the stream or drainage basin in which it is located, and other information about the location itself. Your second table contains hydaulic data: sample ID (the primary key), station ID (which relates that row to your point), collection date and time, discharge, channel width, and any other relevant information. Your third table contains sediment data: sample ID (primary key), station ID, date and time, each grain category (e.g., silt, clay, fine sand, coarse sand, gravel, cobble), and the percentage or proportion (dry weight?) of each. You could also have additional tables if you want to store more categories of data for each point. Hope this helps, Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user -- Sent from my Android device with K-9 Mail. Please excuse my brevity. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
On Sun, 15 Mar 2015, Paulo van Breugel wrote: The attribute table is in a sqlite table already, unless you are still using dbf as database backend for grass. Just link your other tables to that attribute table? Paulo, Thanks for reminding us. I forgot about that. You are correct that the thing to do is link the other tables to that attribute table. Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
On Sun, 15 Mar 2015, Andy Wickert wrote: EXAMPLE 1: I want to present a time series of stream gage data. I would like a data table to have: time water_discharge_m3_s sediment_discharge_m3_s And to have an entire time series of values for a given grass vector category (i.e. vector point, in this case). Andy, This is a typical database table. Each row needs a unique ID. What I do for all my environmental databases would be something like this: CREATE TABLE Discharges ( site VARCHAR(30), sampdate DATE, -- or use TIMESTAMP to have date and time in a single samptime TIME, -- field. h20disch REAL, seddisc REAL, PRIMARY KEY (site, sampdate, samptime) ) Then assign your points to the site column. EXAMPLE 2: I have a series of data on sediment composition at a river site. For each point, I want to have a 2D data table with multiple values for: grain_size lithology This would have a similar table structure. Columns (attributes) would include sediment sample ID (the table's primary key that refers to a table of sediment samples by location, date, and time), grain size, and lithography. From a statistical analytic point of view I would look at each sample as a composition and apply models suitable for compositional data analysie (CoDA) to them. CoDA was developed by geochemists and is appropriate for your data. HTH, Rich -- Richard B. Shepard, Ph.D. Applied Ecosystem Services, Inc. | Troutdale, OR 97060 USA www.appl-ecosys.com Voice: 503-667-4517 Fax: 503-667-8863 ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Linking multidimensional data to a single point
Dear GRASS users, I have a question regarding attaching data where there may me more than one value per category to a single GIS point. Here are a couple of examples; the first may already be taken care of by the temporal GIS component of GRASS, but the second would not be. EXAMPLE 1: (Possible answer = temporal GIS) I want to present a time series of stream gage data. I would like a data table to have: time water_discharge_m3_s sediment_discharge_m3_s And to have an entire time series of values for a given grass vector category (i.e. vector point, in this case). EXAMPLE 2: I have a series of data on sediment composition at a river site. For each point, I want to have a 2D data table with multiple values for: grain_size lithology Is there any way to include these sorts of multi-dimensional relational data in GRASS? (I say multi-dimensional because I can imagine a standard GRASS table containing links to the full data series, for example.) Thanks for the help! Andy Wickert ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
On Sun, 15 Mar 2015, Andy Wickert wrote: So to boil it down to the simplest part of what you said, the key is just to have an ID column in the GRASS table that links to a table in a database structure outside of GRASS? Andy, Yes. You can keep all point attributes in SQLite (or other rdbms) tables rather than in GRASS. It's been a while since I last did this so the specifics are not immediately available. I would link each point to a table which describes it; perhaps including geographic coordinates, name, and other information. Then your discharge and sediment data are in other tables that are related to each row in the main table. This also allows you to run SQL queries on the data (such as descriptice statistics) outside of GRASS. Just to make sure that I was clear: the problem is how to include multiple rows of data that all correspond to just one point in GIS (so grain size with frequencies in each grain size class or discharge with discharges at different times). Database design is a topic of itself. Separate attribute data from the spatial data; the former goes into a database (multiple tables), the latter in GRASS files. In your initial message you describe three different categories of data and each should be in its own table. Information about each data collection point (which is seen on the map) is in one table. This could include a site ID as the primary key, site name, perhaps the stream or drainage basin in which it is located, and other information about the location itself. Your second table contains hydaulic data: sample ID (the primary key), station ID (which relates that row to your point), collection date and time, discharge, channel width, and any other relevant information. Your third table contains sediment data: sample ID (primary key), station ID, date and time, each grain category (e.g., silt, clay, fine sand, coarse sand, gravel, cobble), and the percentage or proportion (dry weight?) of each. You could also have additional tables if you want to store more categories of data for each point. Hope this helps, Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
On Sun, Mar 15, 2015 at 11:49 PM, Rich Shepard rshep...@appl-ecosys.com wrote: On Sun, 15 Mar 2015, Andy Wickert wrote: So to boil it down to the simplest part of what you said, the key is just to have an ID column in the GRASS table that links to a table in a database structure outside of GRASS? Andy, Yes. You can keep all point attributes in SQLite (or other rdbms) tables rather than in GRASS. It's been a while since I last did this so the specifics are not immediately available. I would link each point to a table which describes it; perhaps including geographic coordinates, name, and other information. Then your discharge and sediment data are in other tables that are related to each row in the main table. This also allows you to run SQL queries on the data (such as descriptice statistics) outside of GRASS. Just to make sure that I was clear: the problem is how to include multiple rows of data that all correspond to just one point in GIS (so grain size with frequencies in each grain size class or discharge with discharges at different times). Database design is a topic of itself. Separate attribute data from the spatial data; the former goes into a database (multiple tables), the latter in GRASS files. In your initial message you describe three different categories of data and each should be in its own table. Information about each data collection point (which is seen on the map) is in one table. This could include a site ID as the primary key, site name, perhaps the stream or drainage basin in which it is located, and other information about the location itself. Your second table contains hydaulic data: sample ID (the primary key), station ID (which relates that row to your point), collection date and time, discharge, channel width, and any other relevant information. Your third table contains sediment data: sample ID (primary key), station ID, date and time, each grain category (e.g., silt, clay, fine sand, coarse sand, gravel, cobble), and the percentage or proportion (dry weight?) of each. You could also have additional tables if you want to store more categories of data for each point. Hope this helps, Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user Hi Rich, This helps very much and learning how to do this will be high on my to-do list. Thank you! Andy ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Linking multidimensional data to a single point
On Sun, Mar 15, 2015 at 4:08 PM, Rich Shepard rshep...@appl-ecosys.com wrote: On Sun, 15 Mar 2015, Andy Wickert wrote: EXAMPLE 1: I want to present a time series of stream gage data. I would like a data table to have: time water_discharge_m3_s sediment_discharge_m3_s And to have an entire time series of values for a given grass vector category (i.e. vector point, in this case). Andy, This is a typical database table. Each row needs a unique ID. What I do for all my environmental databases would be something like this: CREATE TABLE Discharges ( site VARCHAR(30), sampdate DATE, -- or use TIMESTAMP to have date and time in a single samptime TIME, -- field. h20disch REAL, seddisc REAL, PRIMARY KEY (site, sampdate, samptime) ) Then assign your points to the site column. EXAMPLE 2: I have a series of data on sediment composition at a river site. For each point, I want to have a 2D data table with multiple values for: grain_size lithology This would have a similar table structure. Columns (attributes) would include sediment sample ID (the table's primary key that refers to a table of sediment samples by location, date, and time), grain size, and lithography. From a statistical analytic point of view I would look at each sample as a composition and apply models suitable for compositional data analysie (CoDA) to them. CoDA was developed by geochemists and is appropriate for your data. HTH, Rich -- Richard B. Shepard, Ph.D. Applied Ecosystem Services, Inc. | Troutdale, OR 97060 USA www.appl-ecosys.com Voice: 503-667-4517 Fax: 503-667-8863 ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user Thanks Rich, So to boil it down to the simplest part of what you said, the key is just to have an ID column in the GRASS table that links to a table in a database structure outside of GRASS? Just to make sure that I was clear: the problem is how to include multiple rows of data that all correspond to just one point in GIS (so grain size with frequencies in each grain size class or discharge with discharges at different times). Best, Andy ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
