State GeoTIFF and Lidar Data

New Zealand has at least one nationwide GeoTIff elevation dataset available.

There are also many smaller, higher resolution DEM and DTM's available

‘It is very useful to bring in the GeoTIFFs into AutoCAD and then overlay plotted deeds onto the imagery.’

I do exactly that to create paper look for maps for the field when running boundaries. I also drop in county GIS parcel lines then print it out and make my notes on the aerial from the deed descriptions. Occasionally I’ll put the aerial in the DC as well, but usually just look at my papers. I am a bit old school and carry a folder in the vest with deeds and survey plats on every job.

Question for you since you’re a fellow Buckeye; what are you doing (going to do) about the 88 County LDP? How can we make that work in Civil3D?

Regarding county coordinate systems, until the GeoTiffs are reference in the county coordinate systems, my solution would be to start working in the state plane coordinates and import state plane coordinates into my data collector and then transform those coordinates to the county system inside the data collector. Then the county coordinates could be exported out of it.

...what are you doing (going to do) about the 88 County LDP? How can we make that work in Civil3D?

Autodesk does a pretty good job keeping up with new coordinate systems. If you're not able to grab the latest version of civil 3D you can add the new definitions to MAPCSLIBRARY.

Dave

I like to create a geotiff out of the DEMs available online here in New York. Stone walls and other occupation lines show up nicely and are usually accurate within about 3 feet.

Pennsylvania has a lot of data online, hosted by Penn State at a site called PASDA (Pennsylvania Spatial Data Access). In addition to statewide lidar and imagery data sets spanning multiple years, it also has historic aerial photos since the 1930's (Penn Pilot), as well as mine maps. I have downloaded the mine maps for my property, here is what it looks like...the floor elevation of the mine in that area is about 829 feet (NGVD29), my house is at 1223 ft. The coal mine closed many years ago.

www.pasda.psu.edu

Vermont has a site, https://vcgi.vermont.gov/ with extensive data available. Quite a bit of it can be viewed with their interactive map viewer. The whole range can be accessed as services that work with ArcGIS Pro desktop and other software. It would take quite a bit of work to figure out all the forms in which data can be accessed and which software is compatible.

@ashton

Thats a nice service - loads of good data there.

But 'caveat empor' - I see that they deliver the parcels WFS data in terms of Web Mercator - so not exactly survey accurate...

WFS data in terms of Web Mercator – so not exactly survey accurate…

Has anyone done a study to determine the expected accuracy between Web Mercator and an SPC? I realize that there would be a lot of caveats, and the methodology would be key to understanding the results. I ask because I have had past projects with clients that wanted to work in Web Mercator. I would guess that ESRI and GIS have this hammered out...

This is a bit outside my normal area of work, but there is this article:

https://community.esri.com/t5/data-management-questions/nad1983-2011-to-wgs-1984-web-mercator/td-p/638850

@jimcox There is a web page that contains the parcel metadata at https://maps.vcgi.vermont.gov/gisdata/metadata/CadastralParcels_VTPARCELS.htm and it says its SPCS Vermont zone. There is also a page where the data can be downloaded in several formats:

https://geodata.vermont.gov/datasets/VCGI::vt-data-statewide-standardized-parcel-data-parcel-polygons-1/about

I'm not sure how to examine the downloaded data to see what format it purports to be in. I suppose I could find a point in the raw data and see if the values look anything like SPCS. Another approach would be to find an NGS monument that lies on a parcel boundary, but I can't think of any.

Apart from the problems created by the projection, there is the obvious problem of trying to piece together surveys performed over the past 250 years into a parcel fabric.

@ashton

I was looking at the webservices section of this page

https://geodata.vermont.gov/pages/parcels

It suggests that such data is in web mercator

If I go the endpoint for the WFS service listed, I get the capabilities of the server. It indeed confirms that both active and inactive parcels are in those terms

Of course, it is possible for Downloads to be in a different coordinate system

Extract from the server capabilities:

<wfs:FeatureTypeList>

<wfs:FeatureType>

<wfs:Name>FS_VCGI_VTPARCELS_WM_NOCACHE_v2:Cadastral_VTPARCELS_poly_inactive</wfs:Name>

<wfs:Title>Cadastral_VTPARCELS_poly_inactive</wfs:Title>

<wfs:DefaultCRS>urn:ogc:def:crs:EPSG::3857</wfs:DefaultCRS>

<ows:WGS84BoundingBox>

<ows:LowerCorner>-73.42128978 42.72995280</ows:LowerCorner>

<ows:UpperCorner>-71.54007965 45.00977947</ows:UpperCorner>

</ows:WGS84BoundingBox>

</wfs:FeatureType>

<wfs:FeatureType>

<wfs:Name>FS_VCGI_VTPARCELS_WM_NOCACHE_v2:Cadastral_VTPARCELS_poly</wfs:Name>

<wfs:Title>Cadastral_VTPARCELS_poly</wfs:Title>

<wfs:DefaultCRS>urn:ogc:def:crs:EPSG::3857</wfs:DefaultCRS>

<ows:WGS84BoundingBox>

<ows:LowerCorner>-71.80190954 44.78555562</ows:LowerCorner>

<ows:UpperCorner>-71.80123951 44.78590786</ows:UpperCorner>

</ows:WGS84BoundingBox>

</wfs:FeatureType>

</wfs:FeatureTypeList>

While I have not used them in years, New Jersey has aerial photos in State Plane, they were called Mr. Sidds, not sure they still are. They were free to download and I used them in the same fashion as you, overlaying deed plots on the aerials, based on physical features. It was great for creating search points.

We also have free, downloadable LIDAR for the whole state but we don't use it for anything other than presentation purposes.

I use NC's free orthoimagery daily and the lidar derived surface as supplements and additional checks against blunders for aerial lidar missions. I think North Carolina is on its sixth statewide lidar survey. The benefits to the public are enormous.