| Entering Values Into OSA Shapefiles Using The Field Calculator | |
| To fill or update calculated values: 1. when you are done adding shapes to shapefile, save edits, and put table in edit mode; 2. clear any previous record selections (un-highlight the lines); 3. click on the field name of choice (example used "Sitearea"') in the table to select it; 4. click the Calculate  button to bring up Field Calculator; 5. doubleclick the appropriate source object in the listing (so that it appears in the lower formula box) and choose the needed output type (i.e., for filling in the Sitearea field which is formatted as a number, we utilize the [Shape] field because all the feature geometry is stored invisibly in it, the "." says we're requesting something from that [Shape], and the ReturnArea specifies what we're requesting from it (this formula has no spaces in it -- some with pluses and other operands may or may not need spaces); 6. then click the spot for the Type of resulting value you're going to fill into the table's field (i.e., in this case, Number); 7. hit OK. |
SHAPE field | Fills automatically whenever a shape is added to the shapefile/theme. |
| ID field | Enter consecutive numbers beginning with 1 (regardless of site number). Or, save previous edits to the shapefile, select the ID field, and use the Field Calculator with this formula: rec + 1 |
| SITE field | Enter the entire Site Number. Or (if the COUNTY, NUMBER, and optional MODIFIER fields have already been dealt with), select the SITE field, and use the Field Calculator with this formula: "13" + [County].AsString + [Number].AsString + [Modifier].AsString |
| COUNTY field | Enter the 2-letter Smithsonian county abbreviation for the site in capital letters (i.e., for 13JH311, enter JH). There is an on-line list of these county abbreviations (disregard the numbers therein). |
| NUMBER field | Enter the number assigned to the site by the OSA Iowa Site File (i.e., 13JH311 would get 311). |
| MODIFIER field | Blank or enter the modifier assigned to the site; this is done in consultation with the OSA Iowa Site File. One example would be the modifier /AN124 in the site number 13DV105/AN124 (see Designating the Site Number above). |
| SITEAREA field | Select the ID field, and use the Field Calculator with this formula: [Shape].ReturnArea |
| UTM_X field | Select the ID field, and use the Field Calculator with this formula: [Shape].ReturnCenter.GetX |
| UTM_Y field | Select the ID field, and use the Field Calculator with this formula: [Shape].ReturnCenter.GetY |
| DTYPE field | Enter the name of the type of shape which you chose to draw into the view. |