July 11, 2018

Photogrammetry and Location & Surveys Units Products to Support Planning and Design Activities – Should be requested by Central or Division Project Managers Product WHAT It Provides WHAT it is used for Typical Scale WHEN is it typically ordered? Units involved How long to deliver

product?

Controlled Aerial Photography

(individual photo frames)

Overhead frame aerial photographs flown in leaf off flight season in anticipation of formal mapping/surveys request made at a later

date outside of annual request cycle. These flights are typically low altitude flights that cover multiple corridors or alignments

that are still under consideration for selection. Photo identifiable targets used to control the aerial photography are set in advance

of the photo mission.

To have leaf off aerial photography available for out of cycle

mapping/surveys requests. Commonly referred to as “fly and

sit”.

Aerial photos are defined by coverage area,

and planned mapping

product. Use standard scale

for planned mapping product.

Prior to or during leaf off flight season.

When preferred corridor or alignment is selected outside of

leaf off flight season. Best Practice

Annual Mapping/Surveys Request Cycle

When Necessary Out of Cycle

Photogrammetry plans flight and control configuration,

and acquires photos. Location & Surveys sets and

ground surveys photo identifiable targets called

“panels”.

1-4 weeks from receipt ofverified aerial photography

limits

Digital Mosaic (raster digital

image mapping)

Project specific georeferenced raster digital image product that aligns with existing statewide geospatial datasets. 2-D raster

digital image (*.sid) file. Raster digital image products do not have a scale. The Ground Sample Distance (GSD) of a pixel defines the product detail. This product has no vertical information derived from its photo mission. Existing statewide LiDAR elevation data available upon request. Municipal property data available upon

request.

Used for corridor studies, functional design work, and corridor selection

for large projects. Can be used to detect and identify

land cover change in dynamic areas as project development and design

are ongoing.

Standard 0.5 ft GSD

(use 1”=100’ or 1”=200’)

Alternative use 1”=400’ for

1.0 ft GSD use 1”=50’ for

0.25 ft GSD

Start of project development. Existing statewide orthophotos are old or do not reflect current

land cover. Best Practice

Annual Mapping/Surveys Request Cycle

When Necessary Out of Cycle

Photogrammetry plans flight, acquires photos, and

produces mapping. No Location and Surveys

involvement.

1-3 months after aerial photography completed.

Requires receipt of verifiedmapping limits in advance

of photo mission.

Orthophotography (raster digital

image mapping + DEM with TIN)

Project specific georeferenced raster digital image product with elevation data that aligns with existing statewide geospatial

datasets. 2-D raster digital image (*.sid) file, 3-D (digital elevation model) DEM (.dgn) file with 20 ft spaced elevation points and

break lines on roads and significant water features, and corresponding triangulated irregular network (TIN) file. Municipal

property data available upon request.

Used for corridor studies, functional design work, and corridor selection

for large projects where both horizontal and vertical accuracy is

required. This is the most common coverage ordered during planning studies for new location projects.

Standard 0.5 ft GSD

(use 1”=100’ or 1”=200’)

Alternative Upon request

Prior to functional and preliminary design activities.

Best Practice Annual Mapping/Surveys

Request Cycle When Necessary

Out of Cycle

Photogrammetry plans flight and control configuration,

acquires photos, and produces mapping.

Location & Surveys sets and ground surveys “panels”.

2-4 months after aerial photography completed

and receipt of photo control.

Requires receipt of verified mapping limits in advance

of photo mission

Topographic (T) Mapping (graphic

planimetric mapping including

municipal property +

DTM with TIN)

Project or corridor specific graphic planimetric mapping with municipal property data and more detailed elevation data than DEM product. 2-D microstation design (.dgn) file with limited

detail graphic planimetric mapping including municipal property data, 3-D (digital terrain model) DTM (.dgn) file with 20 ft spaced

elevation points and more detailed break lines than DEM product, and corresponding TIN file. Digital mosaic of photo mission used

to generate topographic mapping available upon request.

Used to support preliminary design activities for larger projects.

Standard 1”=200’

Alternative 1”=100’

Prior to preliminary design activities.

Best Practice Annual Mapping/Surveys

Request Cycle When Necessary

Out of Cycle

Photogrammetry plans flight and control configuration,

acquires photos, and produces mapping.

Location & Surveys sets and ground surveys “panels”,

and field classifies planimetric features.

2-4 months after aerial photography completed

and receipt of photo control.

Requires receipt of verified mapping limits in advance

of photo mission.

Shell Plan Sheet (SPS) Mapping

(graphic planimetric mapping +

DTM with TIN)

More feature and topographic detail than topographic mapping. 2-D microstation design (.dgn) file with highly detailed graphicplanimetric mapping, 3-D DTM (.dgn) file with highly detailed

elevation points and break lines, and corresponding TIN file. This is a lesser product than preliminary plan sheet mapping as it does NOT include field classification of planimetric features. Municipal

property data available upon request. Digital mosaic of photo mission used to generate SPS available upon request.

Used to support preliminary design activities for smaller projects. Usually supplemented with

additional detailed ground surveys to produce Final Surveys.

Standard 1”=50’

Alternative 1”=30’ 1”=20’

Prior to preliminary or final design activities.

Best Practice Annual Mapping/Surveys

Request Cycle When Necessary

Out of Cycle

Photogrammetry plans flight and control configuration,

acquires photos, and produces mapping.

Location & Surveys sets and ground surveys “panels”.

2-4 months after aerial photography completed

and receipt of photo control.

Requires receipt of verified mapping limits in advance

of photo mission.

Preliminary Plan Sheet (PPS)

Mapping (graphic

planimetric mapping +

DTM with TIN)

More feature and topographic detail than topographic mapping. 2-D microstation design (.dgn) file with highly detailed graphicplanimetric mapping, 3-D DTM (.dgn) file with highly detailed elevation points and break lines, and corresponding TIN file.

Includes field classification of planimetric features to final plan sheet specifications. Municipal property data available upon

request. Digital mosaic of photo mission used to generate PPSavailable upon request.

Used to support preliminary design activities for smaller projects. Usually supplemented with

additional detailed ground surveys to produce Final Surveys.

Standard 1”=50’

Alternative 1”=30’ 1”=20’

Prior to preliminary or final design activities.

Best Practice Annual Mapping/Surveys

Request Cycle When Necessary

Out of Cycle

Photogrammetry plans flight and control configuration,

acquires photos, and produces mapping.

Location & Surveys sets and ground surveys “panels”,

and field classifies planimetric features.

2-4 months after aerial photography completed

and receipt of photo control.

Requires receipt of verified mapping limits in advance

of photo mission.

Final Surveys (graphic

planimetric mapping +

DTM with TIN + supporting ground

surveys)

This is the most comprehensive mapping/survey product available. Final Surveys includes all information provided from

Preliminary Plan Sheet Mapping plus the addition of more accurate ground surveys for utility locations, drainage features, pavement elevations, and obscured areas, along with detailed

property survey data.

Used to support Final Design activities.

Base mapping/survey product used for R/W plans and construction

plans.

Standard 1”=50’

Alternative 1”=30’ 1”=20’

Prior to final design activities. Best Practice

Annual Mapping/Surveys Request Cycle

When Necessary Out of Cycle

Location and Surveys performs extensive ground surveys for all required data

content. Photogrammetry provides SPS or PPS when involved.

Varies. Requires receipt of verified

surveys limits.

July 11, 2018

Parameters to Assist Development of Mapping and Survey Limits Many NCDOT STIP projects require various levels of geospatial/mapping/survey data at some point in their project development cycle. The following guidelines may benefit one’s understanding of the different levels of geospatial/mapping/survey data, when the data is used, and where/how the data is derived. Generally speaking, a project may require up to 3 levels of geospatial/mapping/survey data at some point in its development cycle. The limits for this data are frequently referred to as:

Study Area Limits – An over-arching area that encompasses the project and any surrounding features that should be considered as having an impact on the project.

o Existing Geospatial Data is always available, and generally used to address mapping for the study area. Statewide Orthophotos (raster digital image mapping) Statewide LiDAR Ground Elevation Data (typically a DEM with TIN) Municipal Property Data (graphic cadastral data)

o In cases where the study area is changing rapidly due to development and the statewide orthophotos do not reflect current landcover, the Photogrammetry Unit can fly the study area and provide a current Digital Mosaic. Requests can be sent directly to the Photogrammetry Unit or through Regional or Division Location & Surveys staff.

Mapping Area Limits – An area that defines where some level of preliminary and/or final design activity is likely to occur. This area is contained within the Study Area Limits.

o The Photogrammetry Unit and the Location & Surveys Unit generate mapping data within these limits specifically for the project and for the specific design activity that the project requires at that time. Typical products requested include:

Orthophotography and Digital Elevation Model (DEM) Mapping - for new location or larger projects Topographic Mapping – for larger projects

Shell or Preliminary Plan Sheet Mapping – for smaller projects

Data is suitable to use in the development of Final Surveys

Survey Limits (or Final Survey Limits) - An area that defines where final design activity is to occur. This area is usually contained within the Mapping Area Limits but on smaller projects the Mapping Area Limits and Final Survey Limits may be the same.

o The Location & Surveys Unit and the Photogrammetry Unit generate final surveys data within these limits specifically for the project and for final

design activities.

Final Surveys – at time of final design.

July 11, 2018

Parameters to Assist Development of Mapping and Survey Limits

The Location & Surveys, Photogrammetry, and Feasibilities Studies Units have developed the following information as parameters for project managers to consider when delineating Mapping and Surveys limits. This effort is to support the department’s initiative to have mapping and/or survey limits produced as part of the Express Design process.

Typical NCDOT Project, Basic Mapping/Survey Limit Definitions, and Typical Mapping/Surveys Product

Intersection Projects (improve an at grade intersection)

Mapping Limits – Polygon that covers 1,500’ down each Y-Line and ~ 300’ to 500’ left and Right of each centerline.

Survey Limits – Roughly the same as above, may not require the same distance or width on each Y-Line.

Mapping/Surveys Product – Typically goes straight to 1”=50’ Final Surveys.

Interchange Projects (Improve a grade separated interchange or build a grade separated interchange)

Mapping Limits – a custom polygon that covers at least 100’ outside the existing ROW and all the proposed new ROW. Interchange Express Designs willgenerally have multiple design options.

Survey Limits – Roughly the same as above but will only the include area(s) that have been selected for final design

Mapping/Surveys Product – 1”=50’ Shell or Preliminary Plan Sheet Mapping to support selection of the preferred design, then 1”=50’ Final Surveys onthe existing and proposed ROW covering the selected design option.

o NOTE: Interchange Projects may connect with adjacent Interchange Projects. In these conditions, the designs and required limits behave like aWidening Project.

Widening Projects (Significantly improve an existing facility)

Mapping Limits – a custom polygon that covers at least 100’ outside the existing ROW and all the proposed new ROW and 500’ beyond the proposedproject termini. Additional limits down all Y-Lines range from 500’ to 1000’ depending on the facility (entrance into a subdivision vs major urban road).Widening Express Designs will generally have multiple design options.

Survey Limits – Roughly the same project termini as above but limits will only the include areas that have been selected for final design

Mapping/surveys Products – 1”=50’ Shell or Preliminary Plan Sheet Mapping to support selection of the preferred design, then 1”=50’ Final Surveys onthe existing and proposed ROW covering the selected design option.

o NOTE: Widening Projects range from very small projects with very well defined termini to 25 miles or more of improvement including newlocation option to by-pass developed areas. On very large Widening Projects with New Location options, the designs and required limits behavelike a New Location Project.

July 11, 2018

Parameters to Assist Development of Mapping and Survey Limits

The Location & surveys, Photogrammetry, and Feasibilities Studies Units have developed the following information as guidelines for project managers to consider when delineating Mapping and Surveys limits. This effort is to support the department’s initiative to have mapping and/or survey limits produced as part of the Express Design process.

Typical NCDOT Project, Basic Mapping/Survey Limit Definitions, and Typical Mapping/Surveys Product

New Location Projects (Construct new facility on a new location)

• Mapping Limits – a custom polygon that covers at least 500’ outside the existing ROW and all the proposed new ROW and 1000’ beyond the proposed project termini. Additional limits down all Y-Lines range from 1000’ to 1500’ depending on the facility. New Location Express Designs will always have multiple design options.

• Survey Limits – Specific limits developed for the selected corridor.

• Mapping/Surveys Products –o Orthophotography and Digital Elevation Model (DEM) Mapping for corridor studies.o 1”=100’ Topographic Mapping to support selection of the Least Environmentally Damaging Practicable Alternative (LEDPA).o 1”=50’ Shell or Preliminary Plan Sheet Mapping on the selected corridor, limits roughly following criteria for a Widening Project.o 1”=50’ Final Surveys on the selected corridor with limits possibly altered by preliminary design refinements.

July 11, 2018

Controlled Aerial Photography Example

July 11, 2018

Controlled Aerial Photography: many individual frames covering requested area

July 11, 2018

Controlled Aerial Photography: 1 individual frame of many frames

Panel – ground surveyed photo control point

July 11, 2018

Digital Mosaic Example

July 11, 2018

Digital Mosaic: 2-D raster digital image product (NO elevation data)

July 11, 2018

Orthophotography Example

July 11, 2018

Orthophotography: 2-D raster digital image (includes DTM with delivery)

July 11, 2018

Orthophotography: 3-D graphic DEM (limited break lines - roads and drainage)

July 11, 2018

Topographic Mapping Example

July 11, 2018

Topographic Mapping: Digital Mosaic (available upon request)

July 11, 2018

Topographic Mapping: 2-D graphic planimetric mapping (includes municipal property)

July 11, 2018

Topographic Mapping: 3-D graphic DTM (no ground surveyed elevation data)

July 11, 2018

Shell Plan Sheet Mapping Example

July 11, 2018

Shell Plan Sheet Mapping: Digital Mosaic (available upon request)

July 11, 2018

Shell Plan Sheet Mapping: 2-D graphic planimetric mapping (NO classified plan features)

July 11, 2018

Shell Plan Sheet Mapping: 3-D graphic DTM (no ground surveyed elevation data)

July 11, 2018

Preliminary Plan Sheet Mapping Example

July 11, 2018

Preliminary Plan Sheet Mapping: Digital Mosaic (available upon request)

July 11, 2018

Preliminary Plan Sheet Mapping: 2-D graphic planimetric mapping (including field classification)

July 11, 2018

Preliminary Plan Sheet Mapping: 3-D graphic DTM (no ground surveyed elevation data)

July 11, 2018

Final Surveys Example

July 11, 2018

Final Surveys: Digital Mosaic (available upon request)

July 11, 2018

Final Surveys: 2-D graphic planimetric mapping (including supporting ground survey data)

July 11, 2018

Final Surveys: 3-D graphic DTM (including pavement elevations and obscured area elevations)