Presentation on theme: "Bringing Historic Maps into GIS"— Presentation transcript:
1 Bringing Historic Maps into GIS Patrick FloranceDigital CartographerHarvard Map CollectionHarvard University
2 Purpose Demonstrate how historical maps can be used within a GIS. Illustrate the techniques used to bring historical maps into GISShow types of maps that are useful to bring into GISConvey research conducted at the Harvard Map Collection
3 GISA geographic information system (GIS) is a configuration of computer hardware, software, and personnel specifically designed for the acquisition, maintenance, and use of geographically referenced data.Modification of Dana Tomlin’s definition Geographic Information Systems and Cartographic Modeling (1990)
4 Why bring historic maps into GIS? Use historic maps within GIS as a tool for understanding the spatial relationships of past phenomenaDeforestationShoreline changeSocio-economic characteristics of a state or a neighborhoodPlace-namesRailroads and transportation networksDisease
5 Why bring historic maps into GIS? Context: What exists within one’s study area at a given point(s) in time?Overlay modern GIS data over historic mapsEarly 20th century USGS topographic map of central Mass.
6 Why bring historic maps into GIS? Context: What exists within one’s study area at a given point(s) in time?Overlay modern GIS data over historic mapsEarly 20th century USGS topographic map of central Mass.Overlay modern Quabbin Reservoir in semi-transparent blue
7 Why bring historic maps into GIS? Context: What exists within one’s study area at a given point(s) in time?Close up of northern Quabbin over early USGS topographic map.Features flooded: Towns, roads, railroads, etc.
8 Why bring historic maps into GIS? Feature Extraction (heads-up digitizing) and encodingVectorize: discrete data made up of ordered lists of points and represented by points, lines, and polygonsTrace features and encode those graphics with informationSurface of the earthAnthropogenic featuresPlaces, place-names, roads, railways, trails, buildings, bridges, etc.Natural featuresRivers, lakes, shoreline, elevation, etc.Abstract/Administrative geographyCountry, state/province, municipal, parcel/property boundaries, census tracts, etc.
9 Why bring historic maps into GIS? Feature Extraction (vectorization)1898 USGS topographic map of Portland, Maine
10 Why bring historic maps into GIS? Feature Extraction (vectorization)1898 USGS topographic map of Portland, MaineBuilt area extracted (vectorized) in red.Perhaps trace roads, railroads, shoreline, contours, etc.Note edge.
11 Why bring historic maps into GIS? Resource/Research Management ToolMore and more researchers using spreadsheets to manage their research to collect information about places and source materialThink of GIS as sort of a spatial spreadsheet or database, which can be used to join that information to spatial representations
12 Why bring historic maps into GIS? AnalysisSimpleFinding inns that are located within 5 miles of towns with a population over 10,000 in southern France around 1910.More complexArchaeological predictive modelingSpatial analysis techniques to model fire density or disease patterns
13 Why bring historic maps into GIS? AnalysisInterpolated fire density of Constantinople, 1660.
14 Why bring historic maps into GIS? Graphic presentations or visualizationMake maps, charts, graphs, etc.Very powerful and usefulSee David Rumsey Example
15 Historic Map as a GIS Data Source Historic maps are made for communicating, not for serving as a basemap/source data for a modern GIS.Positional accuracy: features often moved slightly for clarity (i.e., clustered places, roads along rivers, etc.)Scale distortionEdge-matchingInsetsPaper streets1890 map vs map
16 Data Conversion/Development Process Convert maps to digital formGeoreference the digital maps: assign them meaningful spatial coordinatesFeature extraction and data modeling ($$)Generally around 80% of project costHeavy overhead before one gets results, which is one of reasons why so many GIS fail.
17 Convert Printed Map to Digital Image Digital Image (Raster) is composed of a grid of pixels1898 U.S. railroad map
18 Convert Printed Map to Digital Image Equipment Large-format scannerExpensiveScarceOverhead digital photographyBe careful using photocopiesDistortion along edges
19 Convert Printed Map to Digital Image Resolution Resolution can be expressed as the number of pixels per inch (PPI)Different from spatial resolution of remotely sensed imagery, which is a measure of the smallest object that can be resolved by the sensor or the dimension on the ground represented by each pixel (i.e., 30 meters)
20 Convert Printed Map to Digital Image Resolution (Cont.) Generally between ppi, average ppiDetermine resolution that captures the smallest significant featureUse consistent resolution if working with a map seriesCapture uncompressed as TIFF (Tagged Image File Format)Consider using image compression for working fileIf map is in grayscale, capture it in grayscale color modelreduce file sizeIf map repository, consider capturing very high quality for archiving & resampling to lower resolution for GIS work
21 Georeference the Digital Image/Map Georeferencing converts a digital image (raster dataset) from a nonreal-world coordinate system (image space) to a real-world coordinate system such as latitude and longitude.Makes it “line up” with other GIS data.Allows the digital map image to be viewed with other GIS data.
22 Georeferencing Process Need to know locations of at least 3 recognizable featuresUse more than 3Locations used to create control pointsSpread out throughout the map1898 U.S. railroad map
23 Georeferencing Process Lat/LongLat/LongLat/LongNeed to know locations of at least 3 recognizable featuresUse more than 3Locations used to create control pointsSpread out throughout the mapLink real-world coordinates to the control pointsLinks used to transform the map image to real-world coordinates
24 Georeferencing: Transformation Transformation adjusts the digital map to make it fit in this real-world coordinate systemAffine Transformation - most commonScaleSkewRotationShift (Translation)
25 Affine Transformation: Scale Changes the image scale by expanding or reducing
27 Affine Transformation: Rotation Rotates x and y axes so that the image is correctly orientedBeforeAfterXY
28 Affine Transformation: Shift (Translation) X and Y origin are shiftedBeforeAfterXY
29 Georeferencing: Transformation Complete 1898 railroad map with modern vector shoreline overlaidSoftware creates associated files that contain the coordinate information (i.e., .tfw)Digital map can then integrated with other GIS data
30 Root Mean Square (RMS) error Describes the deviation between the control points in the output image and the values calculated by the transformationA measure of the accuracy of the control pointsIn general, lower number the better, with 0 being perfectRecord RMS errorSave control points
31 Georeferencing Techniques for Historic Maps Use existing coordinates or ticsLink features on map to features within GIS datasets that have known real-world coordinates.Global Positioning System (GPS)
32 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Over 134 types of features: towns, municipal boundaries, road types, railways, hydrology, rice fields, pasture land, post offices, churches, castles, inns, etc.Austro-Hungarian Monarchy Topographic Series,Scale: 1:75,000; Date:
33 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Topographic map misaligned with modern GIS municipal boundaries (red)
34 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Step 1: map researchMap projection: polyhedric projection (antiquated)Coordinate system: Bessel 1841 spheroidSpheroid: estimated shape of the earth as a spherePrime meridian: FerroMetadata is often located on the topographic map itselfHowever, not in this caseSignificant role for the historian
35 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Step 2: Create a point layerFrom geographic coordinates of the 4 cornersBased on the historic coordinate system (Bessel 1841) and prime meridian (Ferro)
36 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Step 3: Project points into the historic map projectionPolyhedric antiquatedUsed a polyconic
37 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Step 4: Link tic marks on the map to the projected corner points.
38 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Step 5: Transform the mapGeoreferenced topo with modern GIS municipal boundaries and rivers overlaid
39 Use Existing Coordinates or Tics to Reference the Map in Real-World Coordinates Close up: modern municipal boundaries (gemeinden) overlaid on topoDisparate datasets never match up perfectlyOff by around feetDetail on map: churches, road types, pastures, etc.
40 Issue: study area falls on edge of a topo sheet
43 Other Useful Maps with Coordinate Systems Topographic seriesUSGS 1890s – 1950s: 1:62500England & Wales: , 1:63,360German Karte des Deutschen Reiches: ; 1:100,000China Ministry of National Defense Land Survey: ; 1:100,000Survey of India: ; 1:253,440.Nautical chartsShorelines, soundings, etc.World and regional mapsHistoric places, national and provincial boundaries, transportation networks, etc.Globes
44 Georeferencing Techniques for Historic Maps Use existing coordinates or ticsLink features on map to features within GIS datasets that have known real-world coordinatesGlobal Positioning System (GPS)
45 Feature LinkingUse control points to link features on the map to features within a GIS dataset that have known real-world coordinates2001 MassGIS Digital Orthophoto1797 Street Map of Boston
46 Feature Linking Steps Acquire GIS reference dataset to link the map to Should be of equal or slightly better scaleMap researchMap projection, coordinate system/datumIdentify additional map sources for referenceEstablish reference points to use as linksCultural features such as street intersections, bridges, buildings, landmarks, monuments, etc.Try to avoid using natural features such as shoreline, rivers, lakes, etc. because they fluctuate greatlyCheck dates of features on the map used as linksProject GIS data to match the projection of the map
47 Feature Linking Steps (Cont.) If georeferencing multiple maps, start with the most current map and work backwards in timeProvides more features to link to1797183518952001
48 Feature Linking Steps (Cont.) Add at least 3 control points spread out throughout the mapTransform the map2001 MassGIS Digital Orthophoto1797 Street Map of Boston
49 City-Wide Maps: Boston Useful for tracing the historical development of:StreetsDistricts & wardsShorelineTown boundariesMonumentsChurchesSchoolsSignificant buildingsshoreline change
50 City-Wide Maps: Cambridge Full View 1865 street map of the City of Cambridge, MA
51 City-Wide Maps: Cambridge Detail Detail of 1865 street map of the City of Cambridge, MA
52 City-Wide Maps Georeferenced Georeferenced 1865 map of CambridgeGIS reference dataCity of Cambrige GIS street centerline (shown in red)
53 Integrate Additional GIS Data with Georeferenced Map Georeferenced 1865 map of Cambridge overlaid with 3D buildings
54 Integrate Additional GIS Data with Georeferenced Map Georeferenced 1865 map of Cambridge overlaid with 3D buildings and modern shoreline of the Charles River
55 Urban/Fire Insurance Atlases Publishers: Bromley, Beers, Hopkins, Sanborn, Ordnance Survey (OS)Begin around mid 19th century, early 1800s for OS.Scale of 1:5000 or betterWealth of informationProperty: boundaries, owners, addressesBuilding: footprints, composition, heights, stories, use, roof typesOther info: streets, fire hydrants, etc.
56 Urban/Fire Insurance Atlases Detail Detail of 1867 Boston Sanborn
57 Urban/Fire Insurance Atlases Full View IssuesBound editions make digital conversion difficultInsetsMosaicing or edge-matchingUngeoreferenced 1867 Boston Sanborn
58 Urban/Fire Insurance Atlases Georeferenced Mosaic Full View Georeferenced 1867 Boston Sanborn with inset mosaiced
59 Urban/Fire Insurance Atlases Georeferenced Mosaic Detail Georeferenced 1867 Boston Sanborn with inset mosaiced
60 Urban/Fire Insurance Atlases Integration of Modern and Historical Data Georeferenced 1867 Boston Sanborn with modern buildings overlaid in red
61 Reconstructing the New Orleans Yellow Fever Epidemic of 1878 Andrew Curtis & John Anderson, LSU Example of using historic urban atlases and city-wide mapsTextual descriptionsAutomated data conversionHistorical geocoding of death residencesSpatial Analysis
62 Other Useful Types of Maps Census MapsMost common requestEnormous amount of vectorization workScarceMinor Civil Divisions, NY, 1930.
63 Other Useful Types of Maps Aerial PhotographyVertical photography from mid 1930s to present; developed during WWIIGreat for contextDistortion/displacement: scale, relief, and tiltUse building footprints not rooftops, street intersections, etc. for control points19522001Boston 1952 USDA aerial photo over 2001 MassGIS color orthophoto
64 Other Useful Types of Maps Map to Map GeoreferencingCompare one map to anotherDon’t need real-world coordinatesMap of Paris, 1832Map of Paris, 1865
65 Georeferencing Techniques for Historic Maps Use existing coordinates or ticsLink features on map to features within GIS datasets that have known real-worldGlobal Positioning System (GPS)
66 Global Positioning System (GPS) A system of satellites & receiving devices used to compute positions on the Earth
67 Global Positioning System (GPS) Collect ground control points for significant features on the map: building corners, street intersections, monuments, site remains, etc.Lat/Long1815 map of early 16th century waterworks in Istanbul
68 Global Positioning System (GPS) Useful for georeferencing when one does not have any reference data or coordinates on the mapPrimarily used for city-scale or larger scale maps, not for maps of very large regions
69 Georeferencing Techniques and Historic Maps for GIS Use existing coordinates or ticsLink features on map to features within GIS datasets that have known real-world coordinatesGlobal Positioning System (GPS)
70 Rubber SheetingExpression is used many different ways
71 Rubber Sheeting“The process of transforming an image from one x,y coordinate system to another”ArcInfo manualIncludes linear (Affine) transformations
72 Rubber Sheeting Higher order transformations (warping) 2nd order or higher (nonlinear) that transform through curvesNeed minimum of 6 control pointsMaps of large areas and unknown projectionAerial photography
73 Rubber Sheeting Piecewise Transformation Uses different transformations in different parts of the mapUsed when map is badly warped and data matching is essentialUsed for edge-matchingGenerally use a full transformation firstHow does one record this in the metadata?Sometimes easier with vector data
74 Rubber Sheeting - What to Do? Start with a first-order (Affine) transformationResearch projection of your mapFind good control pointsUnderstand there is a fuzziness of inaccuracy in all maps and GIS data.Then move on to higher order transformations and then piecewise transformations
75 Getting Started Source Materials Historic & contemporary mapsMap & government document librariesSpecial collectionsArchivesGovernment agenciesCommercial vendorsGIS dataUniversitiesLibraries
77 Getting Started Hardware Computer with minimum 512 megs RAMFor large processing 1-2 gigs of RAMAccess large format scanner or overhead digital photography
78 Getting Started People GIS skillsUsually takes about 1 to 2 weeks to get up to speed
79 Do you need to bring your historic map into a GIS? Maybe NOTMaking a map of an historical period.Using the map as reference to encode pre-existing GIS data.Digitizing tabletto extract/trace features.
80 General Future of Bringing Historic Maps into GIS History of cartography community needs more research concerning technical aspects (i.e., map projections and coordinate systems), mentioned by David Woodward at ICHC 2003GIS community needs to develop more historic projections, coordinate systems, and transformations.Development of geo-historical datasets that can be widely usedmust include metadataAccuracy assessmentOutreach concerning the use and significance of historical materials for GIS
81 Future of Bringing Historic Maps into GIS at the Harvard Map Collection Harvard Library Digital InitiativeGeoreferencing and disseminating maps online through the Harvard Geospatial Library (HGL) as JPEG2000Civil War collectionEarly AfricaChinese toposHistoric USGS toposExperimenting with automated raster to vector data conversionConducting workshops and developing instructional materials concerning GIS and the humanities/social sciences
82 Useful Internet Sites The Harvard Map Collection Harvard Geospatial LibraryDavid Rumsey Map CollectionThe Boston Atlas