dhis2-devs team mailing list archive

[Knut Staring <knutst@xxxxxxxxx>]

An additional remark about the new way of handling thematic layers:

When using GeoJSON files one would only see layers that were actually
available. The new setup, all orgunit levels are listed. I think this
is as it should be, but there is no way to tell whether there actually
are any coordinates in the db for a specific level, and if you then
select it, the module hangs. We may need to think of a way to indicate
whether there are in fact any map data available (of course, it may
also be the case that we have coordinates for only some facilities, so
that a layer is partially available).

Knut

(PS. They level selection box comes out as a bit too small for me in Chrome)

On Sat, Oct 30, 2010 at 7:48 PM, Knut Staring <knutst@xxxxxxxxx> wrote:
> The latest improvement of the GIS module means we now have the ability
> to make maps for a limited area of a country (e.g. a province) but
> also select what level that should be visible for this area (e.g.
> districts or subdistricts). This means that having polygon coordinates
> in the orgunit table now provides more functionality than the previous
> method of fetching separate GeoJSON file layers for each level from
> the file system, which now seems redundant. I think it therefore may
> be time to remove the functionality which supports these "external"
> files, since the process of converting the common shapefile format to
> GeoJSON and uploading is very similar to converting to GML and
> uploading.
>
> This means that people will no longer have make the somewhat confusing
> choise of a mode for thematic layers ("GeoJSON or database"), and we
> can remove the functionality of visually matching polygons to orgunits
> in the database. However, we should keep the ability to add
> non-thematic layers as GeoJSON files for overlays (e.g. roads, rivers,
> cities, airports). Such additional layers (as well as background
> layers) can also be added as WMS  using a local Geoserver or external
> services.
>
> Also, there are questions as to maintenance of orgunit polygons as
> administrative boundaries change. And perhaps most importantly, it
> would be very nice to be able to create the orgunit hierarchy based on
> shapefiles, rather than having to ensure the hierarchy is already in
> DHIS2 and matches the shapefile names (see below). I think we should
> encourage the use of a "Parent" column in the DBF file, and add the
> ability to recognize this column in the GML import. Alternatively, I
> suppose we could describe a good method to create the hierarchy in
> Excel based on a collection of DBF files.
>
> In order to link with other data, it would also be good if the
> OpenHealthMapper interface would also be able to specify thematic maps
> from a service like Geoserver, but that may be a larger effort.
>
> The documentation also needs to be updated to reflect the new import
> method. Below is a description of the current process importing from
> shape files. Though this is not something people do very often, we
> should probably aim to simplify it over the medium term.
>
> 1. First you need to make sure that all the orgunits for which you are
> adding polygons are in DHIS2, and that there is a field in each .dbf
> file which has this name. The spelling must be identical for DHIS2 to
> be able to match, so change any deviant spellings.
>
> 2. You then need to use the free tool ogr2ogr to convert your
> shapefiles into GML format. On Linux you can just do apt-get install
> ogr2ogr.
> For Windows, you should download FWTools, http://fwtools.maptools.org/
>
> 3. Now open a command window and navigate to the folder with the
> shapefiles, and issue the following command (replace "output" and
> "input" with the actual names):
> ogr2ogr -F GML output.gml input.shp
>
> 4. The column in the .dbf file with the orgunit name will have been
> converted to an XML element inside the GML file. Open the GML file in
> a text editor (e.g. Notepad++) and do a search/replace to make sure
> this element is called exactly ogr:Name (case sensitive), e.g.
>
> <ogr:Name>Badjia</ogr:Name>
>
> 5. Import the GML file into DHIS through the regular import interface
> (no need to zip it)
>
> 6. In the GIS module, make sure the Administrator - Map Source setting
> is set to DHIS database.
>
> In the Polygon Layer screen, you can then select the orgunit from the
> tree which appears by clicking on the Parent orgunit field.
>



-- 
Cheers,
Knut Staring