Aerial Topographic Mapping. (WBS 12102) Deliverables: Aerial Topographic Mapping 2-D and 3-D DTM
Aerial Topographic Mapping. The scope of work for this task was to update the project mapping to reflect the recently completed Phase 1 improvements. To update the mapping, the final CADD files for the Phase 1 improvements were merged with the previous topo file. Field survey was also conducted, and cross sections were developed at 50’ intervals to confirm the accuracy of the Phase 1 improvement plans. Based on the comparison of the field survey data to the Phase 1 improvements, several unforeseen inconsistencies were noted, specifically related to the final grading conditions. Additionally, Caltrans recently constructed a safety improvement project along the WB on-ramp and the City has restriped the Xxxxxx Beach Drive/Eucalyptus Avenue intersection, which were not reflected on the project topo. To reduce the risk of further differing site conditions, an updated aerial topo file is recommended. The updated aerial topo will increase the accuracy of the bid quantities and result in a reduction in CCO’s during construction. The limits of the topo will include the entire Phase 2 project limits including a portion along Ironwood Avenue related to the Line K-1 improvements. • Task 2.1.2 – Aerial Topographic Mapping o Updated Aerial Topo (90 hours and Subconsultant cost = $32,350) The original scope of work for the project was based on scoping discussions with Caltrans where minor utility coordination was required for updated utility mapping and notification letters. Based on discussions with the Project Development Team (PDT), it has been noted that additional services are required to complete the utility certification for the project, including: ⮚ New utility agreements (EMWD, Frontier) – Will reduce cost/schedule as agreements will not require City Council approval ⮚ Utility Encroachment Exception (EMWD) – New Caltrans requirement ⮚ Coordination for the electrical service transfer from SCE to MVU – New project feature ⮚ Coordination for inclusion of agency plans and specifications (MVU, EMWD, SCE, Line K-1) – Will reduce bid costs and provide construction schedule efficiency • Task 2.5 – Utility Coordination o Preparation of Utility Agreements for EMWD and Frontier (225 hours) o Preparation of Utility Encroachment Exception for EMWD (125 hours) o Coordination with SCE and MVU for electrical service change (SCE to MVU) (75 hours) o Coordination with agencies to develop and prepare final plans and specifications (75 hours)
Aerial Topographic Mapping. The surveyor shall capture LiDAR point cloud data and aerial photography using aircraft mounted sensors at an altitude equivalent to the width (1400 feet) of the project. LiDAR data shall be processed using TxDOT style feature code library to identify all ground-based features. Ground feature collection, DTM, Triangulated Irregular Network (TIN), DATA (DAT) files, and 1- foot contours shall be extracted from the LiDAR point cloud data, supplemented with ground- based GPS and Ortho -rectified photography. Aerial processing and feature collection shall include but not be limited to, all visible surface utilities including, overhead power lines and associated service poles, drainage structures, text and inscriptions on roadway regulatory signs (excluding text and inscription for advertising signs ), mailboxes, driveways, parking areas, building footprints, edge of pavements, creek channels, grade breaks, flow lines, fence lines, ruins, cemeteries, man holes, fire hydrants, and any other feature visible and appropriate for 1” = 50’ scale mapping. The processed LiDAR data shall be cut into tiles that match the aerial photography and ground-based survey and reduce the file size of the individual tiles to no more than 10mb each. The Surveyor shall incorporate all previous tasks into Task 4 and deliver the final product on duplicate digital media acceptable to the City. Deliverables: A DTM with 1-foot contours including ground-based Flow Line and outfall structures in MicroStation 2D and 3D file format. LiDAR point cloud data in LAS file format cut into tiles that match the aerial photography. A TIN file cut into tiles that match the aerial photography and LiDAR point cloud data. A separate DAT and ASCII file cut to match each associated aerial photography and LiDAR point cloud tile. In addition, orthorectified mapping at the appropriate scale with all requested planimetry will be provided. One copy of all deliverables in electronic format on external digital media is required.
