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<br />. <br /> <br />w <br />. <br />~ <br /> <br />. <br /> <br />. <br /> <br />lOX Loupe - allows interpreter to see ditches, fences, etc. <br />Map-O-Graph transfer machine - alleviates scale differences <br />between photos and base maps <br /> <br />Preparation <br /> <br />"':>. <br /> <br />1) Mount mylar on orthophoto quad with drafting tape. The mylar must <br />be fastened securely at the corners and on the edges. The use of <br />drafting tape allows for easy overlay removal. Failure to secure the <br />mylar will allow the overlay to move while drafting and produce a <br />poorly registered map. Proper registration of the map to real world <br />coordinates is critical to construction of the database. <br />2) Label the overlay with the quad name and add the 16 tic marks of the <br />1927 datum (not 1983). Accurate positioning of the tic marks is <br />required for proper map registration. Label the latitude and longitude <br />of the 4 corner tics. The tic marks should be labeled in ink but the <br />map name and lat/long should be written with a film pencil which <br />will not be detected by the scan digitizer. <br /> <br />Manual Cartography <br /> <br />1) If the interpreter is right handed, start working in the upper left hand <br />corner. of the quad and work across and then down the page in order <br />to reduce smudging. If the interpreter is left handed, start with the <br />upper right corner of the quad. <br />2) The field outlines (polygons) should be delineated as accurately as <br />possible, drawing lines which are smooth and are not broken. All <br />polygons must be closed if the mylars are to be scan digitized so the <br />ARC/INFO coverage created from the scanned data will not require <br />excessive clean up. If the digitizing will be done by hand, the <br />polygons should be closed but it is not imperative. <br />3) Only agricultural lands are included in this survey; cultural features <br />(parks, football fields, golf courses, etc.) and riparian vegetation <br />should not be delineated. <br />4) Single lane roads, used to separate fields, should be drawn with one <br />line down the center of the road. Lines which are very close together, <br />less than 1/20th inch separation, cause problems when scanned at <br />300 dots per inch into ARC/INFO. <br />5) When an orthophoto quad is not available, a 7.5 minute topographic <br />quad is used as a base map instead. The Map-O-Graph transfer <br />machin.e is used to project the information from the photos onto the <br />quad sheet and to remove scale differences between the photos and <br />the quad sheet. The Map-O-Graph is also used when the fields on the <br />photo do not appear on the orthophoto (newly cleared fields, addition <br /> <br />3 <br />