Import/Catalogue/Merced County Buildings

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Merced County Association of Governments has building footprints, addresses and other digital files that can be imported into OSM. GIS Analyst Natalia Austin was very helpful in quickly answering questions and confirmed that the files are public domain and can be freely used. The county has both addresses and building footprint files available. They may update the data in the future, but the county only does it as it has time and doesn't have a specific time schedule, so this will probably be a one-time import, although it may be worth checking back in the next couple years to see if they have made any major updates in either of the files. The import will include information merged and conflated into one file.

I have downloaded the few buildings already in the county and have verified that none overlap with existing buildings. I left the existing buildings in place as much as possible and merged any existing address nodes or pois manually with the new buildings. Unfortunately not every building in the county was digitalized, but most address points were. Where there was a direct one-to-one relation, I merged the address point with the building outline. When more than one point occupy a building, the nodes were kept separate from the building outline. I added 100s of buildings manually from imagery so blocks would have the missing outlines rather than just the address node.

Import Plan Outline

Review the data then upload.


To add buildings and address points for Merced, CA


Would like to complete by November, 2014.

Import Data

From the county's website.


OSM Data Files

The JOSM file is available for review at

Import Type

One-time import with the possibility of future updates

Data Preparation

Shapefiles been edited in QGIS, Excel and JOSM to avoid most conflicts and saved in JOSM format.

Data Reduction & Simplification

The files included the name and type of business. The extra category allowed them to be matched to their corresponding OSM tags. Both name and OSM category have been included when possible, and the original tags were deleted. The shapefile created unnecessary relations with several of the buildings near each other. These have been manually removed as much as possible, leaving just the tags. I have gone through and tried to make sure the addresses that are not conflated with the buildings are as close to the building as possible and there are no overlapping address points or extra floating address points that don't correspond to anything. I expanded the street abbreviations and converted to proper case items that were in all caps.

Tagging Plans

In addition to the standard address information, I included the tags swimming_pool and spa = yes or no on some of the buildings when they were available. I'm not sure if this information should be in OSM, but it would be easy to take off these tags first if there is an objection.

Changeset Tags


Data Merge Workflow

Verifying with existing data in JOSM

Team Approach

This will primarily be a solo endeavor but I am open to any advise or suggestions.


Using both Bing aerial and existing OSM data to verify.


Converting shapefiles with JOSM, simplifying, verifying data in JOSM with existing areas and imagery, uploading, reverting with JOSM revert script if there are problems


Downloading existing buildings and pois uses JOSM and Overpass api and comparing with existing areas.