DRAPP Product QAQC Participating Partner Process Guidelines Steve Ashbee ASPRS Certified Photogrammetrist PMI Project Management Professional Sanborn

Transcription

1 DRAPP Product QAQC Participating Partner Process Guidelines Steve Ashbee ASPRS Certified Photogrammetrist PMI Project Management Professional Sanborn Program Manager

2 Area naming and other general feedback Appendix C DAT Criteria Sanborn QAQC process Overview of Workflow and Orthophoto QAQC Guidelines for participating partners Examples of product issues to report for editing Examples of characteristics inherent to orthophoto product that can be expected Considerations in determining an edit call Temporal differences at seam lines Strip to strip Mission to mission Questions/Comments Agenda 3/12/ , The Sanborn Map Company, Inc. 2

3 Current Area Naming Naming corresponds to highest available resolution or, in case of Area 3, Summer Flight designation. 3/12/ , The Sanborn Map Company, Inc. 3

4 Responses to other Comments/Questions Some technical issues with getting "locked out" (for QC) Updates to GeoServe have included adding a buffer or queue to input processing that will prevent issues that arose as input was supplied by multiple users simultaneously. Would like some tips/instruction on the proper way to load imagery into our environment (mosaic dataset) We would be glad to help with this but would need more information with respect to the specific environment you area working in and the infrastructure you are using. 3/12/ , The Sanborn Map Company, Inc. 4

5 Responses to other Comments/Questions The WMTS connection seemed really slow. I thought it would improve the farther along the project went, but it is so slow that we can't use it consistently in ArcMap This may be a user specific issue. Sanborn s testing has shown that the ArcMap accesses WMTS quickly and performs well. If the user has a machine with limited RAM and/or an older version of ArcMap running, it will render imagery slowly regardless of the data source. ArcGIS 10.5 and earlier versions have known issues with rendering WMTS that were fixed in ArcGIS (from 51-IssuesAddressedList_ pdf) These include: 1. BUG : ArcMap crashes when displaying Web Map Tile Services (WMTS) on a Windows 10 machine 2. BUG :ArcMap fails to fetch tiles from a non-arcgis Server Web Map Tile Service (WMTS) service secured with web-tier authentication by not parsing the URL correctly with a '?' to initiate a query string 3/12/ , The Sanborn Map Company, Inc. 5

6 Sanborn subjects all orthophoto products to a thorough QC process to ensure contract specifications are met such as: Positional accuracy Time of exposure to ensure minimum solar altitudes met Image displacement along seams Radiometry mismatch at seams and at tile joins Warping of structure features such as bridges or buildings Warping, (sometimes referred to as smearing ), of surface features due to DEM errors Blurred imagery Imagery blemishes such as pixel voids color anomolies Clouds Sanborn QAQC Process Excessive building lean obscuring 25% or more width of adjacent transportation features Radiometry, (color, contrast, brightness), are adjusted on globally on a project area basis. Since radiometry preferences can be somewhat subjective, the approach has been to survey preferences and apply the adjustment that meets user majority preferences. Pilot Areas are then submitted for review Once radiometry is accepted it is applied project wide 3/12/ , The Sanborn Map Company, Inc. 6

7 Partner QAQC Work Flow/Guidelines Web access to review completed orthophoto product provided through Sanborn application: GeoServe Separate GeoServe projects are provided for each product resolution Procedure demonstrated/reviewed for users through on-line web meeting prior to Product QAQC Phase Additional GeoServe instructions and QAQC Guidelines provided in Orthophoto QA Guidelines document provided to QAQC Participating Partners 3/12/ , The Sanborn Map Company, Inc. 7

8 Examples of Issues ID d for Edit Hard line between tiles A clear difference in radiometry between tiles evident at tile join 3/12/ , The Sanborn Map Company, Inc. 8

9 Examples of Issues ID d for Edit Blurry-Hazy Imagery Areas that exhibit blurriness compared to surrounding imagery 3/12/ , The Sanborn Map Company, Inc. 9

10 Examples of Issues ID d for Edit Bridge Deformation Bridges warped or otherwise deformed due to missing data. This is caused by image being rectified to ground level. These structure distortions should be remedied by either creating a bridge surface in the DEM model or patching in raw imagery to represent the structure. 3/12/ , The Sanborn Map Company, Inc. 10

11 Examples of Issues ID d for Edit Seam line through Structure Seam lines should not pass through structures. The building should come from a single image since structures elevated above the surface will be displaced in different directions from each exposure perspective. 3/12/ , The Sanborn Map Company, Inc. 11

12 Other Issues: Examples of Issues ID d for Edit Moving objects such as cars on roadways are not typically removed or considered for seam line editing. However, larger objects such as the aircraft below may obscure details and can usually be eliminated by using imagery from an adjacent photograph to produce orthophotos over the affected area. 3/12/ , The Sanborn Map Company, Inc. 12

13 Other Issues: Examples of Issues ID d for Edit Extreme solar reflections that obscure interpretation of adjacent detail can usually be remedied by replacing the affected area with imagery from an overlapping photograph. 3/12/ , The Sanborn Map Company, Inc. 13

14 Examples of Characteristics Inherent to Orthophotography Power lines don t line up at image seam: Power lines are above surface and therefore subject to radial displacement. Imagery is rectified to a single elevation at any given location. For orthophoto mapping the ground elevation is use to rectify the imagery. 3/12/ , The Sanborn Map Company, Inc. 14

15 Examples of Characteristics Inherent to Orthophotography Structures leaning in different directions or shadows cast in different directions: Structures on opposite sides of a seam line will be displaced radially relative to their respective photo centers. In some cases shadows will be cast in different directions as well depending on the time of day the adjacent image was captured. 3/12/ , The Sanborn Map Company, Inc. 15

16 Examples of Characteristics Inherent to Orthophotography Moving Cars partial or double image: Only stationary objects can be in their correct location. A moving object may be represented in the imagery multiple times or as a partial vehicle. This is because tiles are composed of multiple images mosaicked together. It is possible manually edit by pixel cloning but due the additional time and cost it is not typically part of an orthophoto mapping deliverable. 3/12/ , The Sanborn Map Company, Inc. 16

17 Examples of Characteristics Inherent to Orthophotography Minor reflections car windshields, solar panels, waves on water bodies: Car windshields, solar panels, and waves will present many different angular aspects relative to the sun and sensor. Some incidents of reflection will almost always be present with respect to these features. No editing is necessary if there no impact to the interpretability of the map features. 3/12/ , The Sanborn Map Company, Inc. 17

18 Examples of Characteristics Inherent to Orthophotography Trees leaning in different directions or shadows cast in different directions: In forested areas the seam lines will necessarily cut through trees with this result. Ground features will align but tree tops will not due to radial displacement. Lighting and amount of tree shadow on the canopy may also give the false impression of radiometry change. 3/12/ , The Sanborn Map Company, Inc. 18

19 Questions/Comments 3/12/ , The Sanborn Map Company, Inc. 19