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Fugro EarthData, Inc.

Fugro EarthData, Inc. Texas Benthic Phase 2: San Antonio Bay Image Evaluation. Contents. Water Clarity Some areas of San Antonio Bay look turbid and the turbidity might be obscuring some of the oyster reefs and other benthic features

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Fugro EarthData, Inc.

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  1. Fugro EarthData, Inc. Texas Benthic Phase 2: San Antonio Bay Image Evaluation

  2. Contents • Water Clarity • Some areas of San Antonio Bay look turbid and the turbidity might be obscuring some of the oyster reefs and other benthic features • This could result in some of these features not being mapped • However, enhancing the images visually brings out some of the features a bit more, so the information may be there in the data and may actually get delineated and classified through Definiens and CART • Test segmentations indicate that by adjusting parameters, better polygon delineations of oyster reefs can be achieved

  3. Contents • Water Clarity – San Antonio Bay 2007 Ultracam displayed without any stretch Oyster reefs not easily seen Google Earth Oyster reefs easily seen

  4. Contents • Water Clarity – Mission Lake, San Antonio Bay 2007 Ultracam Looks very turbid, benthic features (grass, oysters, or algae?) only visible on eastern side Google Earth More clear, can see more benthic features throughout the lake

  5. Contents • Water Clarity - Oysters RGB displayed without any stretch Reefs are barely discernable Same area showing green band only with a 2 standard deviation stretch

  6. Contents • Water Clarity – Oysters, Polygon Tests Scale 20 polygons created using all 4 bands Some reef boundaries not captured Also scale 20 polygons but only using the green band and slightly different parameters Reef boundaries better

  7. Contents • Pixel Speckling Within Vegetation • Vegetation (upland and emergent) appears speckled in the Ultracam imagery while it is much more smooth and homogenous in the 2004 NAIP • We don’t think this is going to have a major effect on the segmentations or CART classification

  8. Contents • Pixel Speckling Within Vegetation 2007 Ultracam Light and dark pixels mixed within vegetation NAIP 2004 Vegetation much more smooth and homogenous

  9. Contents • Color Balancing • Balancing between image frames is bad in a few spots • more noticeable in vegetation in CIR • We don’t think this will negatively affect the segmentations but it may affect the CART classification • The classification may not be a big problem though since it looks like it may be isolated to only a couple of bad places

  10. Contents • Color Balancing This looks like the worst place Emergent vegetation different color on each side of the seamline

  11. Contents • Seamlines • Seamlines prevalent due to many image frames • Will definitely affect segmentations but not necessarily classification as long as CART inputs account for any differences • This was not a problem in phase 1, though there were fewer seamlines since the flight lines were larger strips rather than many frames • We don’t think this will be a big problem

  12. Contents • Seamlines As long as features on each side of the seams are classified correctly, dissolving at the end will eliminate the apparent seams. This shouldn’t be a problem in open water areas, but other benthic features may require a little more work on the CART side.

  13. Contents • Summary • For most of these issues we don’t think they will result in any significant problems in the polygon segmentations or the CART classifications • It may just be a matter of adjusting segmentation and CART inputs • Some additional labor may be required for this • The biggest potential problem may be the water clarity issue. • We may miss some features • However, tests indicate we can probably get some features that initially look difficult • Will likely require additional labor to do so

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