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sections is expected for the site. The Consultant will survey these cross sections from the found <br />and/or set project control by utilizing a mix of GPS RTK surveying, conventional survey traverse <br />and differential leveling. <br />D. Static Control for Mobile LiDAR. Set two GPS base stations on primary control during <br />the mobile LiDAR acquisition. The base stations will collect static GPS observations at a rate of <br />2Hz simultaneously as the mobile LiDAR collection occurs. The Consultant will utilize this data <br />to post process the mobile LiDAR vehicle's telemetry which will become the basis for the point <br />cloud. <br />E. Mobile LiDAR Acquisition, Post - processing and Calibration. Employ the use of its <br />Optech Ml mobile LiDAR system to acquire visible features within the apparent right of way of <br />the roadways and alleyways defined in the limits detailed above and shown in Exhibit "A ". The <br />mobile LiDAR system will acquire planimetric and topographic data within the project limits. <br />After acquisition the Consultant will check this data for completeness prior to beginning data <br />calibration. <br />After the Consultant has approved this data for production, the acquired static data and the <br />Consultant will post process the vehicle's telemetry to produce a final trajectory. This final <br />trajectory will be populated with the laser range data, by the Consultant which will produce a <br />final point cloud. The Consultant will calibrate the point cloud to the ground utilizing the mobile <br />LiDAR targets set. This procedure will ensure the accuracy of the final point cloud that will be <br />utilized to produce the deliverables. <br />After the calibration is complete, and prior to beginning extraction, the Consultant will generate <br />a ground truthing report, using the independent ground truthing cross sections collected on the <br />ground. This will test the accuracy of the point cloud away from the calibration control and <br />provide a better idea of the expected accuracy throughout the point cloud. The ground truthing <br />report will show the tested accuracy vs. the expected accuracy. This is the final step that will be <br />taken to approve the use of the point cloud for extraction. <br />F. Mobile Data Extraction and Supplemental Surveying. Utilizing the calibrated and <br />tested point cloud, extract the following: <br />1) Street Features — Visible above ground street features within the project limits, will be <br />located and design grade data extracted at approximately 50 -foot stations, as well as <br />any major grade breaks, within the design survey limits described above. These <br />features include paint striping, back of curb, face of curb, gutter line, edge of <br />pavement, crown of road and pavement type changes. <br />2) Drainage Features — Visible above ground drainage features within the Project limits <br />will be located. Manhole inverts, pipe size, type and flow direction (if accessible) <br />will be acquired utilizing conventional surveying field crews. The Consultant will <br />only uncover manholes that can be accessed without the use of traffic control or lane <br />closures. Survey location or schematics of subsurface drainage culverts or structures <br />is outside of this scope of services. <br />CITY HALL • 630 EAST HOPKINS ® SAN MARCOS, TEXAS 78666 ® 512.393.8150 ® FACSIMILE 855.759.2846 <br />SANMARCOSTX.GOV <br />5 <br />