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This is a project to import some public domain data from Baltimore City's GIS division. The data is available free at


All OpenStreetMap editors contribute to OSM. However these users are working primarily on this project:


Here is a short list of the intended results for the map

  • Import the building footprints city-wide
  • Consider replacing streets with those from the dataset
  • Import neighborhood boundaries
  • Import water features
  • Import vegetated area coverage


The following will be followed

  • Community involvement
  • Accuracy
  • Documentation
  • Respect other edits
    • There may be data that represents real world changes since this GIS data was published.
  • Attribution
    • Though in the public domain, we should still reference the creator


This project began in July 2012. Current stage is:

Early planning/testing --ElliottPlack 19:18, 13 July 2012 (BST)

Loyola University Test

I uploaded a small portion of the building footprint dataset around Loyola University to test the upload procedures and that it works.

Loading map...

There were some duplicate issues perhaps due to having to use Potlatch to import the data. I will try again with Notre Dame (to the north) using only JOSM and see what happens.

Secondary Test Results

I sent this to another mapper, and it sums up this test:

Wow, JOSM is def the way to go. It's built from the ground up for this task. Forget the ESRI plugin, potlatch, or any other method, JOSM is the way to go.

Tonight I was messing around and wanted to add the northern part of Loyola and then Notre Dame's campus. Existing in this area was a puny road that is now a parking lot and building names as points.

My procedure was fairly straightforward. First I downloaded and installed QGIS which is a FOSS GIS client. I needed that to save out certain areas. I learned the basics of that software quickly but I do think arcmap would be faster/easier with its advanced selection and clipping features. I'll look into QGIS more but that point is really irrelevant. Anyway I saved out some shape files for the campus roads and the buildings.

Next I opened up JOSM and installed the open data plugin that allows shape files to be opened natively. I added the shape files for the roads and building that I previously clipped. In JOSM you can easily select the entire dataset and change the tags at once. I removed all the city data fields for the buildings because they were all junk data. I added the building = yes tag to all the building ways.

Next were the roads. Before I updated any roads, I first downloaded the OSM live data for the area and then deleted the existing roads. Then I selected the new roads and did the same stuff as above. Now all the data was good to go.

Validation. This is the most redeeming feature of this software. You run a tool and it finds all the errors. Duplicated nodes and ways can be fixed all at once with one click. There's a bunch of different warning types like when street ways don't intersect properly or when things that normally shouldn't overlap do. Like buildings and streams.

Once validated I looked at this point features. I just copy pasted the tags from point to poly and then deleted the points. Too easy!

Now, when we go city wide, it will only be cumbersome where there already are buildings. Roads and other named features are tricky because the names are often in all caps so I need to look into scripts to change case.

Bottom line this is fully possible and not too hard.