On Tue, Nov 2, 2010 at 10:01, Jason Pickering <jason.p.picker...@gmail.com>wrote:
> Hi there. Not entirely sure what the problem with using MapFish and > Geoserver are actually. There are plenty of examples of how the two > can be used together. After all MapFish is simply a client, Geoserver > simply a server capable of producing formats that MapFish can render. > Yes, no doubt about that :-) We've used Geoserver as a GeoJSON feeder for MapFish for quite a long time ourselves (map source type: shapefiles). So if Geoserver will be used to provide let's say a GML stream, they surely can work together. My Geoserver/MapFish point was a comment to the suggestion of having Geoserver do what MapFish is currently doing in OHM as well. Geoserver is a powerful tool which we could take advantage of. But I don't think we should rely on Geoserver in the terms of "integrating" it. What I am trying to say is that the client should deal with input formats, not tools. If the client accepts the provided format, it doesn't matter who produced it. > > I think the meat of Knuts suggestion is simply that OHM should be able > to 1) consume and 2) integrate data sources from other sources. I see > that the first is essentially already done. It could be a bit more > simple to add WMS layers (have noet checked this for a while, perhaps > it is easier). Integration of external data is a much tricker subject, > but with the work that has been done with importing XML streams/SDMX, > I am not really sure why it could not be done. After all, Geoserver is > fully capable of exporting data as GML, which is just XML. If a > seperate transform (XSL-T) needed to be develop to transform GML to > SDMX/DXF, this would seem to be feasible. > For me the major use case for integration is the importation of of > data from external parties. The major use case I can think of is the > importation of data from a data provider that may use "complex" data > sources, such as remote sensing data, to produce risk maps, or > predictions of rainfall, which are often linked to malaria incidence > for instance ( I am thinking about NASA, IRI, and other meterological > institutes). For instance, a data provider could provide a predicted > level of malaria incidence for each district in a country, publish > this data through Geoserver or other WFS server, and DHIS/OHM could > then consume this data in the form of GML. The production of this type > of data would usually well beyond the capabilities of most clients of > DHIS2 to produce, but they could certainly use the data if 1) it was > published in a standards based format and 2) DHIS2 could make sense of > it. I am not sure we should focus so much on the integration with > Geoserver, but more with the ability to import GML as an XML stream, > which Geoserver or other WFS sources (such as ArcGIS server, > Mapserver, etc) are really good at producing. > > As for the issue with PostGIS, again,I think at some point, people > will start to develop their own queries using PostGIS. With the query > functionality of DHIS2, it should be possible to develop queries like > "Give me all health centers with a utilization rate lower than 50% who > are within 10 km of a facility that has a utilization rate greater > than 100% for the year 2010.". This type of query would help to > reallocate resources from clinics with high load, to those with lower > loads. However, I suspect that these types of queries are going to be > very ad-hoc, very specific to certain situations. The major advantage > that I have encountered using PostGIS is the ability to create spatial > views, which are treated by Geoserver as a seperate layer. No need to > maintain multiple layers, simple write a view, and you have the layer > that you want. Now of course, having some nice user-friendly query > interface to do this type of stuff, would be nice. But as we all know, > the current query interface is only sufficient for all but the most > simple of data base queries. Once people need other views of the data, > they have to develop them themselves (e.g. the PivotSource queries). > > I agree with all of Knut's points, but it always comes down to > resources and priorities to implement what other clients have already > done (e.g. a Time slider in Google Earth, ESRI's web framework). > > Regards, > jason > > > On Mon, Nov 1, 2010 at 6:05 PM, Jan Henrik Øverland > <janhenrik.overl...@gmail.com> wrote: > > There are some good suggestions here, like the general idea of making OHM > > more susceptible to other data sources. However, relying as much on > > Geoserver as mentioned here basically means starting from scratch in our > > case as OHM is based on MapFish. Also, I think using PostGIS violates the > > DHIS principle of database independency. > > On Sat, Oct 30, 2010 at 20:55, Knut Staring <knu...@gmail.com> wrote: > >> > >> Forwarding to the developer list > >> > >> On Thu, Oct 28, 2010 at 3:47 PM, Jan Henrik Øverland > >> <janhenrik.overl...@gmail.com> wrote: > >> >> From: Knut Staring <knu...@gmail.com> > >> >> To summarize what I currently see as the next major GIS improvements: > >> >> > >> >> 1) Points displayed with different sizes or graphical symbols, not > >> >> just colored circles > >> >> > >> >> 2) Showing a lot of data for a point when clicking on it (typical use > >> >> case is showing a kind of profile for a health facility, for example > >> >> all values for a special indicator group as a first go). > >> >> > >> >> 3) Geoserver as alternative datasource for thematic layers - > >> >> substantial expansion of available functionality > >> >> > >> >> 4) Support for multidimensional data elements and indicators > >> >> > >> >> 5) Access control like rest of DHIS. Not everyone should be able to > >> >> set administrative settings > >> >> > >> >> 6) Reenabling the export to Excel and PDF (why did they disappear?) > >> >> > >> >> 7) Data import from surveys etc. - with optional automatic assignment > >> >> of points based on coordinates > >> > >> Adding a point 8): We currently represent time as just another > >> dropdown box. It would be really nice to have a time slider like e.g. > >> Instant Atlas, ArcGIS or this (flash) example : > >> http://labs.slate.com/articles/slate-job-map-unemployment-rate/ > >> > >> In general in DHIS2, we may need to improve our handling of time > >> series outputs, perhaps even for input. Point 2) can be related to > >> time series. The user should also be able to relatively easily > >> calculate *differences*, e.g. between one month and the next, or even > >> from March 2009 to March 2010. Such differences are interesting to > >> map, and can show which areas seems to be improving for a particular > >> indicator, as in this example: > >> http://drop.io/inup25f/asset/unemp-change-png > >> > >> > 1, 2 and 5) Covered by blueprints for 2.0.6 and 2.0.7. > >> > >> Good. We may need to update them as we progress. > >> > >> > 3) Geoserver is already an alternative datasource for the thematic > >> > layers in > >> > OHM. When it comes to expansion of functionality it would be nice if > >> > someone > >> > that knows Geoserver well could summarize what we could take advantage > >> > of, > >> > whether it requires special database add-ons like PostGIS etc. > >> > >> Right, Geoserver can act as a Web Feautre Service which outputs > >> GeoJSON, so it is possible to upload shapefiles to Geoserver instead > >> of importing them (using GML) to the orgunit table. However, I was > >> thinking of adding a supplementary mode, which would allow for > >> connection to external data (e.g. in an Excel file or an RDBMS). > >> > >> I see two possibilities for such an alternative mode: > >> > >> 1) The user's dropdown selections would be communicated to Geoserver, > >> and Geoserver provides the styling, rather than the styling happening > >> in the client, like in the previous OH functional prototype. However, > >> I suppose it would mean that the dropdowns would also have to be > >> populated from the external datasource? Needs more thought. > >> > >> 2) The GeoJSON file that is generated by Geoserver (by linking to > >> DHIS2 or other data sources) can contain all the relevant data, and > >> the dropdown box selections will then only be filtering (if there are > >> more than one indicator) and styling in the client. > >> > >> Using PostGIS is in many ways the best option, especially since we are > >> recomending Postgres now. I think we could require it for some > >> advanced functionality. However, Geoserver will work nicely with > >> shapefiles. > >> > >> I also think we have to consider how to deal with 4), as I can imagine > >> people will want to see a map Males vs a map of Females, for example. > >> > >> > 6) PDF was removed because of the presence of image export. With the > PDF > >> > functionality followed a lot of code, dependecies, libraries, a print > >> > servlet and a widget in the already crowded left side of the viewport. > >> > The > >> > image export solution is a lot neater and, in my opinion, covers the > >> > necessary functionality. > >> > Two months back there were some problems with the image exportation. > >> > Both > >> > image and Excel export were temporarily removed (the Excel sheet > >> > contains an > >> > image). When the problem was fixed there was a consensus that the > Excel > >> > sheet is currently not very valuable. We may put it back in if you > want. > >> > >> Ok, thanks for the explanations - I think we can keep it as it is, > >> especially if the removal also reduced the size of the OHM > >> considerably, since it is by far the heaviest module. > >> > >> I liked the combination of having the data along with the map as > >> export, but I am not sure if this is a real use case (people may > >> prefer a full export or a pivot table). If it is, we could just export > >> the data as CSV. > >> > >> Point 7, on importing external data is in a way an alternative to the > >> Geoserver mode I discuss above. I think both options may need to be > >> developed, since the particular use case would favor one or the other. > >> > >> Knut > >> > >> _______________________________________________ > >> Mailing list: > >> https://launchpad.net/~dhis2-devs<https://launchpad.net/%7Edhis2-devs> > >> Post to : dhis2-devs@lists.launchpad.net > >> Unsubscribe : > >> https://launchpad.net/~dhis2-devs<https://launchpad.net/%7Edhis2-devs> > >> More help : https://help.launchpad.net/ListHelp > > > > > > _______________________________________________ > > Mailing list: > > https://launchpad.net/~dhis2-devs<https://launchpad.net/%7Edhis2-devs> > > Post to : dhis2-devs@lists.launchpad.net > > Unsubscribe : > > https://launchpad.net/~dhis2-devs<https://launchpad.net/%7Edhis2-devs> > > More help : https://help.launchpad.net/ListHelp > > > > > > > > -- > Jason P. Pickering > email: jason.p.picker...@gmail.com > tel:+260968395190 >
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