Harvesting ArcGIS Online Data and Maps Metadata

This short article describes a process where Python was used to harvest metadata from a list of identified ArcGIS Online maps and the maps’ data services. The data were logged to MySQL (with pymysql); a PHP web search and discovery page was created.  The process allows for keyword searching in titles and descriptions of maps and data layers.

Why harvest metadata?

This approach was used as our collection of 150 maps is housed in several AGO organizations with data services spread across even more.  These data and maps are designed for student use and vetted, making school curriculum authors interested in search and discovery of “good” data.  Essentially, we have a target population that is keenly interested in a subset of scattered data and maps.

Who might use this approach?

This article may be of interest to developers needing to create a search solution across a specific list of maps and constituent data services.

The Approach

Using the ArcGIS Python API 1.5.2 and a prebuilt list of mapIds, a script was built that iterates over the list, logging titles and descriptions for the maps.

with open('data/maps.csv') as f:
reader = csv.reader(f)
for map in reader:
result = gis.content.get(map[0])
web_map_obj = WebMap(result)

Using the layers attribute now available for the map object, we then loop over all the layers in the map (above), also logging titles and descriptions.

We then log the data to a MySQL table (with a custom function), like:

  url='http://www.maps.arcgis.com/home/webmap/viewer.html?webmap=' + result.itemid,

Then loop over each layer and log to the table, slightly changing parameters as necessary.

You can access the script at GitHub below. The Python code, a sample CSV input file, and a sample SQL script for generating the MySQL table are included.

github  https://github.com/trbaker/mapHarvest