State GeoTIFF and Lidar Data
Here in Ohio, our state has GeoTIFF and Lidar data for the entire state that can be downloaded from https://gis1.oit.ohio.gov/geodatadownload/.
It is very useful to bring in the GeoTIFFs into AutoCAD and then overlay plotted deeds onto the imagery. The GeoTIFFs are in state plane coordinates so this can often get me within 10' of the actual location of monuments when looking for monuments. I am curious if others bring GeoTIFFs into CAD for surveys and what other states have statewide imagery and lidar data available. I also use the lidar data to create contours when I need them.
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.
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.
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...
