On Thu, Mar 7, 2019 at 11:58 AM David Martin <gs400d...@hotmail.com> wrote: > I'm new to editing OSM, having been a heavy user of OSMAnd for Android for > several years. I primarily use the maps for snowmobiling here in Northern > Michigan, and building my own database of gpx tracks. > > The Michigan maps are lacking the information for state forest land. I have > noted that the Upper Peninsula does have some state and national forest > areas, but there is much missing here in the Lower Peninsula. > > I have found the data on the State of Michigan website, and have successfully > downloaded the shapefile for all state forest land. > > I would like to proceed with adding this data to OSM, with the help of > experienced editors. > > This is public data, available at > http://gis-michigan.opendata.arcgis.com/datasets/dfe0bcec31184b57b9f0d96bc02d6548_1 > > This is high-value data for all OSM users in Michigan, to understand when > they are public land and help prevent trespassing onto private land. I often > have to switch over to Google Maps to see if I am on state land. > > Please advise as to how I may proceed.
A bit of background: I am the original importer of the 'New York City Watershed Recreation Lands' data set, and I re-imported and continue to update the "New York State Department of Environmental Conservation Lands and Campgrounds" data set, so I appear to be the primary custodian of OSM's representation of about 25000 km² of public recreational land. I certainly think that representation of State Forests on OSM is a worthy goal. With that said, an iimport is a really tricky thing to get right. If you're imagining a process whereby you could take a shapefile from Michigan's GIS department and pour it into OSM, it's by no means that simple! A few questions and comments, to get us started -- How familiar are you with OSM mapping? In order for an import on the scale that you're contemplating to be successful, the importers have to be extremely fluent in the editor of choice - most importers use JOSM, and many use external tools in addition. In particular, if you're not familiar with mapping multipolygons, or with 'conflation' - the process of merging data with what's already there - an import is likely NOT the place to learn! I'm surely willing to advise and assist, but I really want to be advising before any major moves, rather than trying to clean up the massive mess that results from a botched import. Anticipating some of the objections: OSM ordinarily does not map land ownership, but only land use, land cover, land access, land protection. What we're going to have here is 'land open to the public - managed by the State of Michigan Department of Xxx - a protected area (IUCN class #nnn) - etc." Those are the salient facts, rather than the fact that the State owns it. Since we routinely map parks, forests, nature reserves, an objection on the grounds that we are dealing with land ownership data can be rebutted on these grounds. How observable in the field is the presence of a state forest? In New York, where state land abuts a road, or where a trail enters or leaves, there is ordinarily signage, comparable to a private landowner's posters, that looks like https://upload.wikimedia.org/wikipedia/commons/3/31/NYS_Forest_Preserve_sign.jpg. In addition, where the road is entering or leaving the forest, turning off to a parking area, or othewise in need of a 'welcome' sign, there will be a larger sign like https://andyarthur.org/data/photo_021252.jpg. Moreover, in the back country, while the posters may be absent, the survey line for the border of the parcel will ordinarily be blazed, either with paint blazes, or for many of the older lines, axe blazes. Axe blazes are visible for decades, even when a tree is nearly healed - https://howtowilderness.com/wordpress/wp-content/uploads/2011/10/blaze.jpg is an example. In general, while it might be possible to stray outside a forest parcel unwittingly if the adjacent landowner has neglected to post, someone who knows the approximate location of a boundary line and is looking for it will find it. If we have "there is signage identifying the forest" and "there is at least this minimal level of field visibility of the boundary", then in my opinion at least, the import clears the bar of 'verifiability.' Now comes the issue of compliance with the import guidelines. https://wiki.openstreetmap.org/wiki/Import/Guidelines . You're already well into Step 2, and doing OK so far. I'd recommend that the next step is to draft an import plan. (This is actually called out as item 2 under step 4, but you'll find that if you approach the 'imports' mailing list without a plan, you'll not get a favourable response.) There's an outline for the plan on https://wiki.openstreetmap.org/wiki/Import/Plan_Outline. For similar imports that I did, you can see the plans at https://wiki.openstreetmap.org/wiki/Import:_NYCDEP_Watershed_Recreation_Areas - this one is a full plan - and https://wiki.openstreetmap.org/wiki/NYS_DEC_Lands - this one is very sketchy, but provided to document the approach to repairing already-imported data. Does the state publish periodic or sporadic revisions to the data set? It's important to think ahead to how the data will be maintained if the state makes changes. For a relatively small data set like state forests of a single state, it's not unworkable to apply changes manually, but it's critical to consider how you'll go about identifying when a parcel has changed. I know that when I apply changes from either of the imports that I curate, I'm in for at least a few evenings of work even with fairly sophisticated tools. If you don't have the tools, then you will surely need a larger team. As a political point, while there's no problem with putting your draft on the Wiki, I'd suggest that before you post to 'imports' or add it to Import/Catalogue, that you run it by some more experienced mappers. (I'm one, Clifford and Martijn, who've already posted in this thread are others, and I can suggest a few more if you email me privately.) Importing is often a bitterly controversial process, and some of the people on 'imports' will jump on the slightest technical flaw as a reason that the import should not proceed. Having the proposal tightened up by a few people who've been through the process helps. Anyway, think some about these considerations, and then there are various folks here who can help. _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-us
