M-NCPPC Import 3.0

Overview

This import project is the successor of M-NCPPC Import 2.0 and will include multiple data sets from the Planning Department of Prince George's County, including building outlines and address nodes. Building outlines and nodes will be combined to a singular dataset for comparison to OSM and upload.

Data

Types of Data

Buildings (polygons)

• Will be merged with address point files in order to give the buildings proper tags.
• This will be split into many pieces following the WSSC Grids in order to create manageable file sizes.
• These two actions will be done in ArcPro.

Data is obtained from http://gisdata.pgplanning.org/metadata/

Example Dataset for import: https://www.dropbox.com/scl/fi/ne16ql5r21snah719v46v/OSM_Updates_220NE07_v2.osm?rlkey=yts8kmhrfx4d2j6sqvkg8qmo6&st=f3j25l2t&dl=0

License

OSM CCBY Permission - March 2026

https://gisdata.pgplanning.org/opendata/

Status

Preparing sample data and comparing changes

The Plan

1. Prepare files to be imported
   • Reduce GIS attributes to only OSM necessary tags
   • If necessary, simplify geometry
   • Break large files into smaller sections (buildings polygon file) using WSSC Grids
   • Join buildings file with address file
2. Communicate with talk-us and import mailing lists to discuss the import
3. Proceed with rest of files over a period of time
   1. Importing Building outlines by WSSC Grid
   2. Used Replaced Geometry method for one-to-many footprint updates for townhomes.
   3. Used Conflate Plugin from the JOSM Editor to update geometry and attributes for one-to-one relationship building footprints
   4. Validator in JOSM will be used before each import
4. After successful imports a QC process using JOSM validator will be used to QC each WSSC Grid

Tagging

Example: Building Outline Shape File → OSM Standards

GIS Attribute Names	OSM Tags
ADDRESS_NUM	addr:housenumber=*
STREET	addr:street=*
CITY	addr:city=*
STATE	addr:state=*
ZIPCODE	addr:postcode=*
HEIGHT	height=*
ROOFTYPE	roof:shape=*

New Attributes that need to be added:

source=M-NCPPC
building=yes

These field names/tags will be changed or added within the JOSM editor. Any additional fields will not be imported. Height was converted from feet to meters in ArcPro.

Conflation

For polygon data such as buildings a comparison has been done using tools in ArcPro between existing OSM data and data from PG Atlas (Data source) to determine if buildings overlap existing buildings in OSM. A separate shapefile has been created of only new buildings. For any overlapping buildings we will manually go through the intersecting buildings in JSOM using the conflate plugin. This includes, but is not limited to, splitting large polygons to create individual building footprints, removing overlaps and removing duplicated building footprints.

Discussion

https://www.openstreetmap.org/changeset/180168476#c1572206

Editor

editor:  M-NCPPC_Import (on OSM)