Greetings MT Editors,

I have added and corrected some GIS Layers available for Montana in WME GIS Layers script. This includes statewide roads, parcels, and addresses.

Note that you can turn these on and off as necessary in the GIS-L control panel - sometimes they may be duplicated in a county you're working in. When GIS-Layers renders these duplicates they can slow your browser down significantly

I've been reviewing the GIS services offered by the Montana State Library Geographic Information Clearinghouse. In particular, the road, address, and parcel layers are particularly useful.

What I have just found and confirmed is that the MSL receives and aggregates road data from jurisdictions throughout the state, and it appears to be very high quality. So counties that otherwise don't have GIS departments or services online, still provide and utilize the MSL service. For counties with GIS departments, they seem to do a good job of regularly providing updates to the MSL. The very latest roads might be available in counties but not MSL, but for the vast majority of roads throughout the state, there is a single statewide road source available. They even include forest service and reservation roads.

I understand that there has been some historical ambivalence regarding "MT Cadastral" parcel data, and I understand like all GIS data, it should be taken with a grain of salt. However, from what I've seen MT is in a pretty unique circumstance in that the MT Dept. of Revenue maintains these records on an annual basis for state property taxes, and for this reason are perhaps more up-to-date than many regions. I think perhaps some of the problems may have been related to which map was being used. From what I've seen, the MSL GIS service is the official and current repository of this information, and we are fortunate that we can query it directly. Yes, property address might change over time, but especially in rural areas where no other information is provided, parcel addresses are great for verifying street names.

Also the MSL maintains a statewide structure layer, that among other things can be used for emergency services, schools, etc. - but also address points in rural areas. These address points appear at driveway entrances in areas that have them - not all areas do, particularly cities.

Let me know if you notice any problems or have any other GIS questions!