Import/Sachsen-Anhalt Naturschutzgebiete

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Goals

Import the Saxony-Anhalt Nature Protection Areas (de:Naturschutzgebiete), as this information is hard to obtain in the field.

The currently mapped Naturschutzgebiete are Import/Sachsen-Anhalt_Naturschutzgebiete/bestehende_NSG

Team Approach

2016 (planning the import): Tbh-osm and g0ldfish. 2017: g0ldfish.

References

Initial thread in german OSM forum: [1]

Schedule

Official discussion period will start when it is

  • posted to imports@ mailing list
  • posted to talk-de@ mailing list
  • posted to the German OSM forum

and will last two weeks minimum.

After discussion, the workflow will be adapted, the actual import will be done manually using JOSM, so approx. a month will be needed.

Start of discussion period: (not started)

Import Data

The nature protected areas (Naturschutzgebiete) dataset from Landesamt für Umweltschutz Sachsen-Anhalt.

The dataset contains the following fields (with example values):

gebietsnam gebietsnum rechtsgrun schutzzone erfassungs info_konta
Colbitzer Lindenwald STNSG0014___ VO v. 26.01.1939 (Amtsblatt der Regierung Magdeburg. - (1939)6 v. 11.02.1939) http://www.lvwa-natur.sachsen-anhalt.de/titel.htm Kernzone TK10AS (1:10000) http://www.metaver.de/trefferanzeige?plugid=/ingrid-group:dsc-adr-ST&docuuid=00F954F0-C8E9-392D-8A48-9FDB307349F8
Colbitzer Lindenwald STNSG0014___ VO v. 26.01.1939 (Amtsblatt der Regierung Magdeburg. - (1939)6 v. 11.02.1939) http://www.lvwa-natur.sachsen-anhalt.de/titel.htm TK10AS (1:10000) http://www.metaver.de/trefferanzeige?plugid=/ingrid-group:dsc-adr-ST&docuuid=00F954F0-C8E9-392D-8A48-9FDB307349F8
Fenn STNSG0008___ VO v. 20.11.1939 (Amtsblatt der Regierung Magdeburg. - (1939)39 v. 30.09.1939) http://www.lvwa-natur.sachsen-anhalt.de/titel.htm TK10AS (1:10000) http://www.metaver.de/trefferanzeige?plugid=/ingrid-group:dsc-adr-ST&docuuid=00F954F0-C8E9-392D-8A48-9FDB307349F8

Background

Data source site: http://www.metaver.de/trefferanzeige?cmd=doShowDocument&docuuid=A16D544B-6DB0-47EA-8285-C1BC2ED2F418&plugid=/ingrid-group:dsc-adr-ST
Data license: see WFS capabilities [2] and written clarification (PDF files below, german)
Type of license: Attribution on Contributors page
OSM attribution: http://wiki.openstreetmap.org/wiki/Contributors#Saxony-Anhalt
ODbL Compliance verified: yes, see PDF files in github repo
Link to permission: yes, see PDF files in github repo

Import Type

This is a one-time import.

The import will be executed manually using QGIS (for preparation) and JOSM for conflation with existing data and uploading.

Data Preparation

Data Preparation

The WFS was read in QGIS by tbh-osm and saved as shapefile. The shapefile was read in JOSM an converted to osm file format. The raw OSM data files are

located in github repo: tilmanb/ST-NSG-import.

Tagging Plans

OSM object tags

This is the source->osm attribute mapping. Objects are simple polygons (closed ways) or multipolygons where required.

source attribute osm attribute transform
gebietsnam name no transformation. Some names have encoding problems with "ß", those will be manually corrected in JOSM.
gebietsnum SGD-ID:ref replace( "gebietsnum",'_','')
rechtsgrun start_date regexp_replace( "rechtsgrun", '.*v. (\\d{2})\\.(\\d{2})\\.(\\d{4}).*','\\3-\\2-\\1')
schutzzone ignored
erfassungs ignored
info_konta ignored

Where the rechtsgrun transform fails, the value will be set manually (for "Alte Elbe bei Bösewig" there is a 2 digit year).

These attributes will further be set

key val
boundary protected_area
source Landesamt für Umweltschutz Sachsen-Anhalt
protect_class 4
protection_title Naturschutzgebiet
leisure nature_reserve

The source dataset contains polygons that are tagged as "Kernzone". Those are conceptually part of the nature reserve, only with stricter access regulations. After discussion, we decided to discard this information, as there does not seem to be any established international tagging concept.

Thus, these polygons have been merged into the regular "Naturschutzgebiet" they belong to (manually, in JOSM).

Changeset Tags

The changeset will be tagged

key val
source Landesamt für Umweltschutz Sachsen-Anhalt
source:metadata http://www.metaver.de/trefferanzeige?cmd=doShowDocument&docuuid=A16D544B-6DB0-47EA-8285-C1BC2ED2F418&plugid=/ingrid-group:dsc-adr-ST
import yes
import_documentation http://wiki.openstreetmap.org/wiki/Import/Sachsen-Anhalt_Naturschutzgebiete

Data Transformation

The attribute transformations are listed in the attribute mapping table.

  • core zones ("Kernzone") have been removed, i.e. integrated in the respective nature reserve ("NSG") geometry
  • disjunct nature reserves and those with enclaves have been transformed into multipolygons
  • missing names have been added and those with charset problems (ß) have been corrected
  • geometries have been simplified using JOSM

These changes are included in the files to be found in the section "Data Transformation Results".

  • Where a Naturschutzgebiet boundary is defined by an administrative boundary, the Naturschutzgebiet boundary will be merged onto the nodes of the administrative boundary, so that the admin boundary remains geometrically unchanged and the Naturschutzgebiet boundary shares the nodes of the admin boundary. The possible definition by an administrative boundary will be checked in JOSM by looking at admin boundaries. If admin boundary and Naturschutzgebiet boundary look suspiciously alike, the act of law defining the Naturschutzgebiet will have to be consulted.
  • Where a Naturschutzgebiet boundary is defined by the shore of a waterbody, the Naturschutzgebiet boundary will be merged onto the existing OSM shoreline. If the OSM shoreline seems way off compared to Bing imagery, the OSM shoreline will be adjusted. The possible definition by a shoreline will be checked as with admin boundaries.
  • Where a Naturschutzgebiet boundary is defined by a highway, the boundary way shall not be merged onto the OSM highway nodes, unless the highway area is additionally tagged with area:highway. Otherwise, the geometry should be adjusted to follow the highway in appropriate distance.

The latter changes will be made right before uploading the data, as existing osm objects may be subjects to changes.

Data Transformation Results

Data Merge Workflow

Workflow

The actual import will consist of the following steps:

  • Load prepared osm files into JOSM
  • Adjust nature reserve borders to administrative borders, waterbodies and roads as described above
  • Upload all new nature reserves in one changeset

Revert plan

  • As this import is restricted to nature reserves that are not mapped yet, the danger of collisions with existing features is minimized. Furthermore the upload is done manually in JOSM, very much as if drawing the polygons from scratch.
  • The changeset number will to provided here, so it can be easily reverted.

Conflation

  • Using JOSM, if a Naturschutzgebiet is already mapped, I will manually refine its geometry to match the import geometry with the least possible number of node changes.
    • If the import geometry and the OSM geometry differ significantly, I will not update the OSM geometry, but note the difference in the table below.
  • Tags will be taken from the import dataset iff this tag is not already set on the osm object. The import geometry will then be ignored, only the existing object will be uploaded in its own changeset.

Conflicts of tags between the preexisting OSM object and the import object will be documented here, community input will be taken on the german OSM forum as to how to deal with the differences.

This will then be done outside of the scope of the import process.

Geometry conflation conflicts

osm id name geometry difference proposed action action performed?
Way 41911105 (XML, iD, JOSM, Potlatch2, history) Jemmeritzer Moor this will be a link to a slippy web map showing the import geometry and OSM background. Those will be loaded as GeoJSON into leaflet hosted at github GIST.

example: [3]

... ...

Tag conflation conflicts

osm id key osm value import value proposed action action performed?
... ... ... ... ... ...

QA

See conflation.

See also / useful links