Map Integration PPT_f
- 1. Annual Meeting 2016 Understanding Map Integration Using GIS Software Michelle Pasco USRIP Symposium
- 2. Introduction to GIS Geographic Information System (GIS) Used to study all kinds of data with a geospatial component Digitizes maps using vector components (points, lines, polygons) Representation of the real world and its attributes Credit: desktop.arcgis.com
- 3. Map Integration Also known as “conflation” Combination of two or more datasets to provide new perspectives and insight on existent geo-enabled data sets May result in a number of problems This project attempted to research and conflate two data sets within GIS Virginia Department of Transportation’s (VDOT) Linear Referencing System (LRS) INRIX XD (XD)
- 4. Study Area
- 5. Issues faced Spatial displacement and attribute disparity Length, position, direction, size, shape Feature representation Unequal updating periods, equal data models acquired by different operators, unequal data models, and content differences
- 6. Methods of Conflation Spatial Join – combines two datasets by comparing their digitized geometries and creating a count recording either features in close proximity or complete matches
- 8. Methods of Conflation Transfer Attributes – matches a feature from one dataset to another feature by selecting one attribute that is similar in both datasets within a certain distance
- 10. Comparison Cases Spatial Join Matching Geographic Coordinate Systems (GCS) vs Original = possibly different GCS (ORG) LRS EDGE (EDGE) vs LRS Non-EDGE (NON) Transfer Attributes Search Distances 0.1 miles 0.3 miles 0.5 miles 1 mile
- 11. Accuracy Assessment Spatial Join: Transfer Attributes:
- 12. Results: Spatial Join Visual representation of spatial join cases on part of I-64. EDGE_ORG EDGE_GCS NON_ORG NON_GCS LRS EDGE = EDGE LRS Non-EDGE = NON XD Original = ORG XD Geographic Coordinate System = GCS
- 13. Results: Spatial Join Road Name & Spatial Join # of features (count>0) features Conflation Accuracy, ca (%) I-64 EDGE_ORG 728 632 86.81 I-564 EDGE_ORG 12 10 83.33 I-95 EDGE_ORG 573 452 78.88 I-395 EDGE_ORG 136 89 65.44 I-495 EDGE_ORG 167 102 61.08 Road Name & Spatial Join # of features (count>0) features Conflation Accuracy, ca (%) I-64 EDGE_GCS 728 359 49.31 I-564 EDGE_GCS 12 10 83.33 I-95 EDGE_GCS 573 287 50.09 I-395 EDGE_GCS 136 27 19.85 I-495 EDGE_GCS 167 30 17.96
- 14. Results: Transfer Attributes Visual representation of transfer attribute cases on part of I-64. 0.1 mile Search Distance 0.3 mile Search Distance 0.5 mile Search Distance 1 mile Search Distance
- 15. Road Name & Search Distance # of features No <Null> features Conflation Accuracy, ca (%) I-64_0.1 mi 754 686 90.98 I-564_0.1 mi 11 8 72.73 I-95_0.1 mi 477 435 97.32 I-395_0.1 mi 64 60 93.75 I-495_0.1 mi 52 50 96.15 Road Name & Search Distance # of features No <Null> features Conflation Accuracy, ca (%) I-64_0.3 mi 754 689 91.38 I-564_0.3 mi 11 8 72.73 I-95_0.3 mi 477 435 97.32 I-395_0.3 mi 64 61 95.31 I-495_0.3 mi 52 50 96.15 Results: Transfer Attributes
- 16. Results: Buffer Tool 0.1 0.3 0.5 Flat Seg 1 1 1 1 1 Seg 2 3 3 3 2 Seg 3 2 2 2 2 Seg 4 2 2 2 1 0.1 0.3 0.5 Flat 4100330 2 2 2 2 4100331 3 3 3 2 4100515 3 3 3 2 Visual representation of the types of buffers on part of I-64. LRS Matching XD Matching
- 17. Conclusions Transfer attributes is overall more accurate Covers the two most important aspects in the conflation process: spatial data and attributes Spatial joining is better to use if the datasets are comprised of many, potentially small, features Either way, larger-scale projects will be more vulnerable to issues
- 18. Questions?
- 19. Acknowledgements Simona Babiceanu, who advised me and kept me on the right track Dr. Emily Parkany, for the constant support Daniela Gonzales, for encouraging me to apply to this program
- 20. References Davis, Curt H., Haithcoat, Timothy L., Keller, James M., Song, Wenbo. Relaxation- Based Point Feature Matching for Vector Map Conflation, 2011. Transactions in GIS, 15(1), pg. 43-60. http://onlinelibrary.wiley.com/doi/ 10.1111/j.1467-9671.2010.01243.x/full. Accessed June 20, 2016. Environmental Systems Research Institute (ESRI). ArcGIS for Desktop, 2016. arcgis.com. Accessed July 18, 2016. G. v. Gösseln, M. Sester. Integration of Geoscientific Data Sets and the German Digital Map Using A Matching Approach. Commission IV, WG IV/7. http:// www.cartesia.org/geodoc/isprs2004/comm4/papers/534.pdf. Accessed June 15, 2016. INRIX. I-95 Vehicle Protection Project II Interface Guide, 2014. http:// i95coalition.org/projects/vehicle-probe-project/. Accessed June 17, 2016. Virginia Department of Transportation. Roadway Network System. Release Notes, Linear Referencing System, Version 15.2, 2015. https://www.arcgis.com/ home/item.html?id=60916ea827544412ad209ea5192ad7fd. Accessed June 2, 2016.