Orthorectification and Distortion Analysis of Historic 1800s San Jacinto Battleground Maps using ERDAS Imagine and an Open Source Tool

Presented by Nancy Heger, Texas Parks & Wildlife (TPWD)

Transcript

1. Orthorectification and Distortion Analysis of Historic 1800s San Jacinto Battleground Maps using ERDAS Imagine and an Open Source Tool Nancy A. Heger Texas Parks and Wildlife Department
2. Importance of Historic Maps ► Documentation of change through time ► Identify areas of archeological significance
3. San Jacinto Battleground ► Site where Texas won its independence ► Currently is §  A State Historic site and State Park §  Site of Battleship Texas
4. San Jacinto Battleground TPWD Staff ►  needed to identify sites of archeological significance before doing restoration work ►  Also interested in change through time Purpose ►  Use historic maps of the San Jacinto Battleground to §  identify sites of historical significance §  Document change through time
5. Methods - 2 Historic Maps Yoakum Map (approx. 1856) McArdle Map (approx. 1892)
6. Yoakum Map (approx. 1856) McArdle Map (approx. 1892)
7. Methods - 2 Historic Maps Yoakum Map (approx. 1856) §  H. Yoakum was a TX Historian; 2 volume History of Texas §  Consulted with Sam Houston about the battle details §  No map scale included §  No evidence that he was a surveyor or cartographer §  Size: 11x19cm or 7.3”x4.6” §  Source: University of North Texas website "Portal to Texas History" at http:// texashistory.unt.edu/ark:/ 67531/metapth2490/ McArdle Map (approx. 1892) §  Artist; Painted the Battle of San Jacinto (1895) §  Extensive battle research; interviewed battle survivors §  Includes map scale §  He served as a mapmaker during the civil war §  Map drawn on back of TX State stationery §  Source: Texas State Library and Archives Commission (TSLAC) at https:// www.tsl.texas.gov/mcardle/ sanjac/sanjac014.html
8. The Battle of San Jacinto
9. Methods ►  Digitized map on a flatbed scanner at 600dpi to create a TIFF ►  Orthorectified by block triangulation using ERDAS Imagine 2011 Leica Photogrammetry Suite (LPS 2011) ►  Potential Problems §  Little detail on maps = difficult to create control points §  Few historic map points to relate to present day §  Was this even do-able?
10. Is there enough detail to create control points?
11. Is there enough detail to create control points?
12. Is there enough detail to create control points?
13. Is there enough detail to create control points?
14. Is there enough detail to create control points? Maybe
15. Is there enough detail to create control points?
16. Is there enough detail to create control points?
17. Is there enough detail to create control points?
18. Is there enough detail to create control points?
19. Is there enough detail to create control points? Maybe
20. Few historic points to relate to present day; extensive change since 1836 battle,
21. Few historic points to relate to present day; easier to relate to 1930 aerial.
22. Few historic points to relate to present day; easier to relate to 1920 topo.
23. Methods – ERDAS LPS Workspace
24. Methods ►  Potential Problems §  Few historic map points to relate to present day §  Was this even do-able? Answer: Maybe ►  Used additional historic maps and imagery to generate control points §  mosaicked 1995 DOQQ §  1920 ed. orthorectified USGS topographic maps §  1930 orthorectified aerial image (Tobin collection)
25. Methods – Reference Imagery 1916 (1920 ed.) Topo 1930 Aerial 1995 DOQQ Timescale 1836 1916 1930 1995 90 yrs 65 yrs Map topo aerial DOQQ 14
26. Methods 1995 DOQQ (Reference Imagery for all) 1920 Topo 1930 Aerial Yoakum Map 1995 DOQQ (Reference Imagery for all) 1920 Topo 1930 Aerial McArdle Map Orthorectification Orthorectification Orthorectified Yoakum Map
27. Initial Orthorectification Products ► McArdle map very problematic; poor fit ► Yoakum map better, but not to our group’s usual standards ► Consulted with an archeologist familiar with site §  Provided insight §  Resulted in much improved results
28. Importance of Archeological Consultation ► Knowledge of historic roads §  movement §  Where evidence is sometimes seen in certain seasons ► Knowledge of dredging and soil movement; when it became more frequent ► Where road to fairy was ► Where historic buildings probably were ► The Canon story
31. Other Helpful Control Points
32. Other Helpful Control Points
33. Orthorectified Products
34. Yoakum Map Original Orthorectified
35. Orthorectified Yoakum Map
36. McArdle Map Original Orthorectified
37. Orthorectified McArdle Map
38. Confirmation of Distortion ► Used an open source tool called Map Analyst ► Made for archeologists to identify map distortion ► Also provides displacement vectors
39. View of Map Analyst
40. Yoakum Map Distortion Analysis
41. Distortion And Displacement
42. McArdle Map Distortion Analysis
43. McArdle Map Distortion And Displacement
44. Distortion Analysis Yoakum Map (1856) McArdle Map (1890’s)
45. Distortion And Displacement Yoakum Map (1856) McArdle Map (1890’s)
46. Other Potential Uses for Map Analyst ► Distortion analysis of any graphically drawn non-GIS map ► Assessment of distortion in orthorectified imagery
47. Conclusions ► Yoakum map is drawn much more accurately than McArdle map ► Yoakum map drawn surprisingly well §  Could be used to identify areas of historical significance and to investigate change through time by TPWD staff ► Used Yoakum map to create an ArcGIS Online application for the public §  to demonstration change in the area from1836 to present.
48. San Jacinto Battleground App
49. San Jacinto Battleground App
50. San Jacinto Battleground App
51. The End