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FREQUENTLY ASKED QUESTIONS
1. How can I place an order?
You can place your order with DES through email. Upon which, DES will provide preview report, shapefile and quotation to confirm your requirements.
2. What is the minimum order size?
| Minimum Order Size |
Archive (sq.km) |
Select Tasking (sq.km) |
| Basic Imagery |
1 scene |
1 scene |
| Basic Stereo (Ortho-Ready Standard World View 1 only) |
210 |
210 |
| Standard/ Ortho-Ready Standard (3-band) |
25 |
90 |
| Standard/ Ortho-Ready Standard (4-band) |
25 |
80 |
| Standard/ Ortho-Ready Standard (8-band) |
25 |
52 |
| Standard/ Ortho-Ready Standard (8-band Bundle) |
25 |
48 |
| Ortho-rectified |
100 |
100 |
3. How can I check my order status?
- Archive Order- DES will confirm the estimate date of delivery through e-mail
- Tasking Order- DES will advise customer on the start and end collection date given by DigitalGlobe.
Tasking Reports will be provided to customer to update the status of the attempts made by DigitalGlobe upon request.
4. Can I charge payment to my credit card? No, we do not accept payment through credit card.
5. What are the payment modes? Payment can be made via Telegraphic Transfer or by cheque.
6. When can I expect my order to be delivered?
Archive order:
DVD - 10 working days after payment is received
FTP – 3-5 working days after payment is received
Tasking order:
DVD – 10 working days upon successful collection
FTP – 3 to 5 working days upon successful collection
7. What are the delivery modes?
There are 4 types of delivery modes.
- DVD
- FTP
- DVD & FTP (dual media)
- External hard disk (Firewire) with additional charges
8. Are there special pricing for larger areas?No.
9. Is there an educational price? What are the requirements? Yes, there is a special price for educational project. Customer must provide the End User Purchase Order to validate if the imagery will be used is for educational purpose. Please ensure that the images are used for non-commercial study or research undertaker solely to further education and not for any commercial exploitation.
How can I define my area-of-interest for purchase?
Customer can provide the Area-Of-Interest (AOI) in the following format:
- Map Projection: Geographic (lat/long)
- Datum: WGS84
- File Format: shapefile / KMZ or KML
If you are unable to provide AOI in shapefile, please provide
- Corner vertices of the order polygon in decimal degrees (lat/long)
- Lat/long of Center point and specify area size.
11. How can I obtain sample imagery?
DES provides sample data imagery on a case-by case basis. You can provide the shapefile of your Area-of-Interest for assessment.
12. Can I place a tasking order for all 3 satellites?
Yes, this is called Combine Sensor imagery. The GSD (Ground Sample Distance) will be according to the strip acquired by DigitalGlobe. Customer can choose either standard or consistent GSD. DigitalGlobe can collect your product requirements and fulfil your order even faster at no additional cost. Consistent should be used when a consistent GSD across the entire AOI is required. Please note that if you select this option and QuickBird is a candidate sensor the entire order will have a GSD of 60cm. The Standard GSD option should be selected when the standard GSD of the sensor is required. This could result in varying GSD over your AOI.
- Customers will have the ability to specify whether they want a color product or a panchromatic product.
- Multi-product orders will be fulfilled using the best available imagery based on cloud cover and collection date.
- Multi-sensor products are not mosaicked or color balanced. Simply put, multiple sensors “paint” the AOI to fulfil the order.
- Ortho mosaic and Stereo product ordering will be limited to single-sensor
13. What are the acceptable polygon shapes?
14. What are the unacceptable polygon shapes?
15. What file formats are available?
NITF 2.0, NITF 2.1, NITF 2.1 NCDRD, GeoTIFF 1.0, Jpeg 2000
16. What are the available product types?
17. What is the difference between Standard Imagery and Ortho-Ready Standard Imagery?
Standard Imagery has a coarse DEM applied to it, which is used to normalize for topographic relief with respect to the reference ellipsoid. The degree of normalization is relatively small, so while this product has terrain corrections, it is not considered orthorectified. Because Standard Imagery has terrain corrections applied, it is not suitable for orthorectification by the customer. Ortho Ready Standard Imagery has no topographic corrections. This product is mapped to the average base elevation of the terrain covered by each individual QuickBird scene. Other than the lack of terrain correction, Ortho Ready Standard Imagery products have all the same specifications as Standard Imagery products. Ortho Ready Standard Imagery can be orthorectified using ERDAS IMAGINE, PCI Geomatica, ENVI, and SOCET SET.
18. How do I know whether I need Standard imagery or Otho-Ready Standard Imagery?
If you are not going to orthorectify your imagery, then a Standard Imagery product will provide a better absolute horizontal accuracy than an Ortho Ready Standard Imagery product. A coarse DEM is applied to Standard Imagery in an effort to minimize the effect of terrain distortions. Because Ortho Ready Standard Imagery is mapped to an average base elevation, the absolute horizontal accuracy may shift from its true location, especially in areas of high relief, if the user does not apply terrain corrections. This will be especially noticeable when comparing a Standard Image with an Ortho Ready Standard Image of the same area. Please note that Standard Imagery and Ortho Ready Standard Imagery both have the same absolute accuracy specification of 23m, excluding viewing angle and topographic displacement. If your goal is to orthorectify your imagery, then Ortho Ready Standard Imagery is recommended.
19. Is it better to othorectify your Basic or Ortho-Ready Standard Imagery?
When using RPCs for orthorectification, both Basic Imagery and Ortho Ready Standard Imagery produce comparable results. When processed using commercial software, RPCs, high quality DEM (e.g. DTED Level 2), and submeter GCPs, accuracies up to 3 meter RMSE can be expected. Slightly better results, up to 2 meter RMSE, may be obtained using the Basic Imagery and the QuickBird Sensor Model with high quality DEMs and submeter GCPs. Ortho Ready Standard Imagery, with a minimum order of 25km2, enables area-based orthorectification. Basic Imagery, with a minimum order of 1 scene (272km2), requires that an entire scene be orthorectified. Note that Ortho Ready Standard Imagery products that are tiled must be mosaicked back together prior to orthorectification because the metadata files are associated with the entire delivered image.
20. Who should order DRA?
- Any customer who doesn’t have the tools to stretch the imagery – or doesn’t want to spend time stretching it.
- If they don’t have sophisticated RS tools on their desktops – GIS users
- “The imagery is too dark. What stretch do I apply to it?”
- “These colors don’t look quite right…”
- “Your 8-bit products don’t have sufficient dynamic range…”
21. Who should not order DRA?
Any customer doing: Spectral classification or scientific analysis
22. How DRA works?
The DRA enhancement consists of two parts:
- Color Correction: data is converted to the spectral radiance domain to get a true color image
- Contrast Enhancement: a non-linear stretch is applied to the image to enhance visual contrast
23. What is off-nadir angle?
Off-nadir angle is the angle between nadir and the point on the ground that the sensor is pointing. Off-nadir angle can be measured along-track (forward) direction or across-track (sideways) direction.
24. What options do I have in selecting off-nadir angle?
The off-nadir angle options are:
25. What is the collection window for tasking new images?
For Tasking Order, DigitalGlobe will suggest a collection period or customer can specify the collection period (up to 365 days). Tasking conditions applies.
26. What is Bit Depth?
Bit depth refers to the amount of energy that is stored in an image. To understand bit depth, you have to relate what you see in an image to the way that computers store data. Computers work with binary data, meaning that every number has a value of 0 or 1. To get more complex numbers, you have to string binary numbers together. For example, a string of two binary numbers (referred to as 2-bit data) would result in 4 possible values: 00, 01, 10, and 11. Take that concept a step further and think about 8-bit data. That would result in 28 or 256 possible values. Applying this back to imagery, 8-bit data allows you to store 256 possible values in each pixel. If you are viewing an image in gray tones, 0 corresponds to black, 255 corresponds to white, and all the levels in between correspond to different shades of gray.
27. What resampling methods does DigitalGlobe offer?
DigitalGlobe offers nearest neighbor, 2x2 bilinear, 4x4 cubic convolution, 8-point sinc, MTF kernel, pansharpening kernel and enhanced kernel as resampling methods.
28. How do the resampling methods work?
When raw data are transformed into a coordinate grid, data are shifted, and it is necessary to use a resampling method to determine what data value to assign to each new, transformed pixel. Each of the methods offered by DigitalGlobe uses different ways to determine what digital number will be assigned to each transformed pixel within the new coordinate grid.
- The nearest-neighbor interpolation is the simplest of the resampling methods. The original pixel value whose center is closest to the center of the new pixel location is used. This resampling method does not modify the original intensity values of the pixels. This method can result in a disjointed or blocky image because no averaging is performed. In addition, some data may be lost or duplicated depending on how the original data relates to the new coordinate grid. This method is preferred for customers who require the original intensity of the pixel values to remain unaltered.
- 2x2 bilinear interpolation involves greater computational complexity. In this approach, the four pixels (2x2 array) in the original image that are nearest to the new pixel location are considered. The DNs from these four pixels are synthesized using a distance-weighted average to calculate the new pixel value. Bilinear interpolation produces a final image with a smoother appearance than an image processed using the nearest neighbor method. Some extreme DN values may be lost, however, resulting in less distinct edges.
- 4x4 cubic convolution is a more rigorous resampling technique that considers the nearest 16 pixels (4x4 array) in the original image that are nearest to the new pixel location. The DNs from these 16 pixels are synthesized using a polynomial calculation. This method produces a smoother appearance than the nearest neighbour method while providing slightly sharper edge detail than the bilinear interpolation method.
- 8-point Sinc uses a damped sinc function [(sin x)/x] within an 8 by 8 window to determine the value of the destination pixel. Theoretically, this is the most rigorous resampling method that is discussed here.
- MTF Kernel uses an 8 by 8 pixel window to determine the value of the destination pixel. This resampling method is optimized for the actual MTF response of the QuickBird sensor and produces sharp edge detail.
29. How do I know which resampling method to choose from?
The resampling method that is right for you depends on your application and the endproduct requirements. For non-pansharpened imagery, the nearest neighbour interpolation is most appropriate for customers who require the original pixel intensity values to remain intact. For example, customers using data to assess vegetative health would probably prefer to use the nearest neighbor method. For other customers who are more interested in the overall appearance of the image rather than the original pixel values, cubic convolution or 8-point sinc is recommended. These methods produce smooth images while maintaining sharp edge detail, making them acceptable for most practical applications. If you are ordering a pan-sharpened product, the DigitalGlobe proprietary, Enhanced kernel or Pan-Sharpening Kernel is highly recommended over all other resampling kernels.
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